Custom Entity Templates – Dynamic Data 4

In Dynamic Data 4 we have Entity Templates these are great for customizing layout of tables (see Walkthrough: Customizing Table Layout Using Entity Templates).  At the moment you will have to create a Custom Entity template for each table, but not only that you will need to create a set of three (Template, Template_Edit and Template_Insert) and that can be useful to have different layout for each view.

But what if you want something different from the Default, (see Grouping Fields on Details, Edit and Insert with Dynamic Data 4, VS2010 and .Net 4.0 RC1 my first custom Entity Template which then had to replace the Default and also had to have all three defined) but not on all your tables just on a selected few?

I was inspired by Brian Pritchard’s post on the forum: How to reduce code duplication when using Entity Template's for only having to create a single template that would switch between Read-Only, Edit and Insert modes.

I want to go a little further:

1. Override the Default Entity Template with some sort of UIHint attribute.
2. An only have to specify one template to keep things DRY
3. Detect if an Edit or Insert version of a template exists and use that.

So now we know out goal, let’s layout the ingredients for this recipe:

1. An attribute to allow us to change the default Entity Template for any given Table.
2. Custom entity factory to allow us to override normal entity behaviour like Brian Pritchard’s.
3. A Custom dynamic Entity Template.

The Attribute

I thought I would be able to use UIHint at class level but alas we have to hand craft our own, I want some of the same feature of UIHint specifically the Control Parameters collection so that we can pass extra information into our custom Entity Templates with out creating a plethora extra attribute each specific to it’s one Entity Template. (I’ve used the Control Parameters collection before in Dynamic Data Custom Field Template – Values List, Take 2.

The Attribute is relatively straight forward, the only complication is the BuildControlParametersDictionary method which takes the Object array passed in using the params key word into a Key, Value Dictionary with some validation. Note we have also set this attribute to be only useable at Class level.

[AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
public class EntityUIHintAttribute : Attribute
{
    private IDictionary _controlParameters;

    public IDictionary ControlParameters
    {
        get { return this._controlParameters; }
    }

    /// 

    /// Gets or sets the UI hint.
    /// 
    /// The UI hint.
    public String UIHint { get; private set; }

    public EntityUIHintAttribute(string uiHint) : this(uiHint, new object[0]) { }

    public EntityUIHintAttribute(string uiHint, params object[] controlParameters)
    {
        UIHint = uiHint;
        _controlParameters = BuildControlParametersDictionary(controlParameters);
    }

    public override object TypeId
    {
        get { return this; }
    }

    private IDictionary BuildControlParametersDictionary(object[] objArray)
    {
        IDictionary dictionary = new Dictionary();
        if ((objArray != null) && (objArray.Length != 0))
        {
            if ((objArray.Length % 2) != 0)
                throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, "Need even number of control parameters.", new object[0]));

            for (int i = 0; i < objArray.Length; i += 2)
            {
                object obj2 = objArray[i];
                object obj3 = objArray[i + 1];
                if (obj2 == null)
                    throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, "Control parameter key is null.", new object[] { i }));

                string key = obj2 as string;
                if (key == null)
                    throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, "Control parameter key is not a string.", new object[] { i, objArray[i].ToString() }));

                if (dictionary.ContainsKey(key))
                    throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, "Control parameter key occurs more than once.", new object[] { i, key }));

                dictionary[key] = obj3;
            }
        }
        return dictionary;
    }
}

Listing 1 – EntityUIHintAttribute

Now we need a method to use this attribute to change the default Entity Template, this factory need to do two things:

1. Change the Default Entity Template based on out new EntityUIHint attribute.
2. Intercept the template mode so that single Entity Template can be used with out having to have three versions.

public class AdvancedEntityTemplateFactory : System.Web.DynamicData.EntityTemplateFactory
{
    public override string BuildEntityTemplateVirtualPath(string templateName, DataBoundControlMode mode)
    {
        var path = base.BuildEntityTemplateVirtualPath(templateName, mode);
        var editPath = base.BuildEntityTemplateVirtualPath(templateName, DataBoundControlMode.Edit);;
        var defaultPath = base.BuildEntityTemplateVirtualPath(templateName, DataBoundControlMode.ReadOnly); ;

        if (File.Exists(HttpContext.Current.Server.MapPath(path)))
            return path;

        if (mode == DataBoundControlMode.Insert && File.Exists(HttpContext.Current.Server.MapPath(editPath)))
            return editPath;

        if (mode != DataBoundControlMode.ReadOnly && File.Exists(HttpContext.Current.Server.MapPath(defaultPath)))
            return defaultPath;

        return path;
    }

    public override EntityTemplateUserControl CreateEntityTemplate(MetaTable table, DataBoundControlMode mode, string uiHint)
    {
        var et = table.GetAttribute();
        if (et != null && !String.IsNullOrEmpty(et.UIHint))
            return base.CreateEntityTemplate(table, mode, et.UIHint);

        return base.CreateEntityTemplate(table, mode, uiHint);
    }

    public override string GetEntityTemplateVirtualPath(MetaTable table, DataBoundControlMode mode, string uiHint)
    {
        var et = table.GetAttribute();
        if (et != null && !String.IsNullOrEmpty(et.UIHint))
            return base.GetEntityTemplateVirtualPath(table, mode, et.UIHint);

        return base.GetEntityTemplateVirtualPath(table, mode, uiHint);
    }
}

Listing 2 – AdvancedEntityTemplateFactory

Listing 1 shows us out AdvancedEntityTemplateFactory, we fulfil task 1. in the methods CreateEntityTemplate and GetEntityTemplateVirtualPath where we check for the presence of a EntityUIHintAttribute and if we find one then set the name of the template to the UIHint property.

Task 2. is dealt with in the BuildEntityTemplateVirtualPath where we check to see if the file exists, if so we just return the path as is, otherwise we strip out the  _Edit or _Insert from the path and return.

The last thing we need is to wire up the AdvancedEntityTemplateFactory in Global.asax.cs

DefaultModel.EntityTemplateFactory = new AdvancedEntityTemplateFactory();

just before the RegisterContext in RegisterRoutes method.

The Custom Entity Template

Figure 1 – Multi Column Entity Template

This entity template will be a multi column temp[late designed to give you a little more screen for your money I have decided to pass the main parameters in via the EntityUIHint attribute’s Control Parameters, in Figure 2 you can see them in pairs.

Figure 2 – Control Parameters

“Columns”, 3 sets the number of column the MultiColumn entity template will show.

The next two pairs are the Title and Field CSS classes.

I’ve also decided to add the ability for some columns to span more then one cell in the table.

[AttributeUsage(AttributeTargets.Property)]
public class MultiColumnAttribute : Attribute
{
    /// 

    /// Gets or sets the column span.
    /// 
    /// The column span.
    public int ColumnSpan { get; private set; }

    public static MultiColumnAttribute Default = new MultiColumnAttribute();

    public MultiColumnAttribute() 
    { 
        ColumnSpan = 1;
    }

    public MultiColumnAttribute(int columnSpan)
    {
        ColumnSpan = columnSpan;
    }
}

Listing 3 – MultiColumnAttribute

The use of Default for when we use the DefaultIfEmpty method in Linq (see my Writing Attributes and Extension Methods for Dynamic Data more info) this allows us to get an attribute even if one is not specified so now with thi sline of code

var totalNoOfCells = metaColumns.Select(c => c.GetAttributeOrDefault<MultiColumnAttribute>().ColumnSpan).Sum();

we can get the total number of cell required with some columns having a span of more than on column see Figure 1.

Finally our Multi Column entity template is completed in Listing 4

public partial class MultiColumnEntityTemplate : System.Web.DynamicData.EntityTemplateUserControl
{
    private const string COLUMNS = "Columns";
    private const string TITLE_CSS_CLASS = "TitleCssClass";
    private const string FIELD_CSS_CLASS = "FieldCssClass";

    protected override void OnLoad(EventArgs e)
    {
        // get columns from table
        var metaColumns = Table.GetScaffoldColumns(Mode, ContainerType).ToList();

        // do not render any HTML table if there are no columns returned
        if (metaColumns.Count == 0)
            return;

        // default the HTML table columns and CSS class names
        int columns = 2;
        String titleCssClass = String.Empty;
        String fieldCssClass = String.Empty;

        // Get the CssClass for the title & Field from the attribute
        var entityUHint = Table.GetAttribute();
        if (entityUHint != null)
        {
            if (entityUHint.ControlParameters.Keys.Contains(COLUMNS))
                columns = (int)entityUHint.ControlParameters[COLUMNS];
            if (entityUHint.ControlParameters.Keys.Contains(TITLE_CSS_CLASS))
                titleCssClass = entityUHint.ControlParameters[TITLE_CSS_CLASS].ToString();
            if (entityUHint.ControlParameters.Keys.Contains(FIELD_CSS_CLASS))
                fieldCssClass = entityUHint.ControlParameters[FIELD_CSS_CLASS].ToString();
        }

        // start in the left column
        int col = 0;

        // create the header & data cells
        var headerRow = new HtmlTableRow();
        if (!String.IsNullOrEmpty(titleCssClass))
            headerRow.Attributes.Add("class", titleCssClass);
        var dataRow = new HtmlTableRow();
        if (!String.IsNullOrEmpty(fieldCssClass))
            dataRow.Attributes.Add("class", fieldCssClass);

        // step through each of the columns to be added to the table
        foreach (var metaColumn in metaColumns)
        {
            // get the MultiColumn attribute for the column
            var multiColumn = metaColumn.GetAttributeOrDefault();
            if (multiColumn.ColumnSpan > columns)
                throw new InvalidOperationException(String.Format("MultiColumn attribute specifies that this 
                    field occupies {0} columns, but the EntityUIHint attribute for the class only allocates {1} 
                    columns in the HTML table.", multiColumn.ColumnSpan, columns));

            // check if there are sufficient columns left in the current row
            if (col + multiColumn.ColumnSpan > columns)
            {
                // save this header row
                this.Controls.Add(headerRow);
                headerRow = new HtmlTableRow();
                if (!String.IsNullOrEmpty(titleCssClass))
                    headerRow.Attributes.Add("class", titleCssClass);

                // save this data row
                this.Controls.Add(dataRow);
                dataRow = new HtmlTableRow();
                if (!String.IsNullOrEmpty(fieldCssClass))
                    dataRow.Attributes.Add("class", fieldCssClass);

                // need to start a new row
                col = 0;
            }

            // add the header cell
            var th = new HtmlTableCell();
            var label = new Label();
            label.Text = metaColumn.DisplayName;
            //if (Mode != System.Web.UI.WebControls.DataBoundControlMode.ReadOnly)
            //    label.PreRender += Label_PreRender;

            th.InnerText = metaColumn.DisplayName;
            if (multiColumn.ColumnSpan > 1)
                th.ColSpan = multiColumn.ColumnSpan;
            headerRow.Cells.Add(th);

            // add the data cell
            var td = new HtmlTableCell();
            var dynamicControl = new DynamicControl(Mode);
            dynamicControl.DataField = metaColumn.Name;
            dynamicControl.ValidationGroup = this.ValidationGroup;

            td.Controls.Add(dynamicControl);
            if (multiColumn.ColumnSpan > 1)
                td.ColSpan = multiColumn.ColumnSpan;
            dataRow.Cells.Add(td);

            // record how many columns we have used
            col += multiColumn.ColumnSpan;
        }
        this.Controls.Add(headerRow);
        this.Controls.Add(dataRow);
    }
}

Listing 4 – MultiColumnEntityTemplate

Updated: MultiColumnEntityTemplate updated by Phil Wigglesworth who kindly found a bug and fixed it, the bug was shown when there were no enough columns left on a row, this caused a crash. So thanks again to Phil.

Also we will need some styles to make out new Multi Column entity template look good.

TR.SmallTitle
{
    background-color: #F7F7FF;
}
TR.SmallTitle TD
{
    font-size: 0.8em !important;
    font-weight: bold;
    background-color: #F7F7FF;
    padding: 2px !important;
}

Listing 5 – CSS styles

Hope this expand your use of Entity Templates.

P.S. I’ll do an updated version of the Grouping entity template.

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Setting the Initial Sort Order – Dynamic Data

This is just a quick note on a post I made on the Dynamic Data Forum to answer a question where setting the DisplayColumnAttribute should set the default sort order of the GridView on the List page but didn’t. Here’s how I solved it with a hint or two from Marcin Dobosz.

[MetadataType(typeof(Orders_Metadata ))]
[DisplayColumn("OrderID", "OrderID", true)]
public partial class Orders
{
    public class Orders_Metadata
    {       
        // ...
    }
}

Listing 1 – Example Metadata

Assuming you have a table with the DisplayColumnAttribute set you could put this on your List page: 

table = GridDataSource.GetTable();

// set default sort
if (!IsPostBack && table.SortColumn != null)
    GridView1.Sort(table.SortColumn.Name, table.SortDescending ? SortDirection.Descending : SortDirection.Ascending);

Listing 2 – Add to Page_Init (.Net 3.5)

// set default sort
if (!IsPostBack && table.SortColumn != null)
{
    var order = new OrderByExpression()
    {
        DataField = table.SortColumn.Name,
        Direction = table.SortDescending ? SortDirection.Descending : SortDirection.Ascending,
    };
    GridQueryExtender.Expressions.Add(order);
}

Listing 3 – Add to Page_Init (.Net 4)

public static T GetAttribute<T>(this MetaTable table) where T : Attribute
{
    return table.Attributes.OfType<T>().FirstOrDefault();
}

Listing 3 – you will also need this extension method see Writing Attributes and Extension Methods for Dynamic Data

Add your DisplayColumnAttribute (see Listing 1) to the table you want sorted (note: it must have the second string constant even if it’s the same name, as the second string it the one that the sort is done on, and the third value if true causes the sort to be descending). Then in Listing 2 you get the attribute using the extension method from Listing 3 and apply the relevant sort.

This is here mainly so I can find it again!

Adding a Multi-Column Search to the Default List page in Dynamic Data (UPDATED)

This will extend the default filters that Dynamic Data provides by adding a free text search box the will search multiple text fields on the same page. I have done this in a few projects now as one off but after this post Custom filters & searches within DD in Visual Web Developer 2010 on the Dynamic Data Forum I decided to document it here.

Figure 1 – Multi Column Search

Here in Figure 1 you can see the multi column search box, in this example the search is on FistName, LastName, Address, City and Country, it will even allow search across entities e.g. on Orders Employee.LastName etc. which make it very flexible.

Things we will need to do

• Attribute to tell the system which columns to search on.
• Add mark-up to show the UI on the List page.
• Code to wire up the UI and QueryExtender.

The Attribute

This attribute will be added to the Class/Table not it’s columns and will have only one property Columns.

[AttributeUsage(AttributeTargets.Class)]
public class MultiColumnSearchAttribute : Attribute
{
    public String[] Columns { get; private set; }

    public MultiColumnSearchAttribute(params String[] columns)
    {
        Columns = columns;
    }
}

Listing 1 – MultiColumnSearchAttribute

and we apply it as in Listing 2 The Employee table show standard multi-column search but the Order table shows how we can search across entity boundaries you can see this in Figure 2.

[MetadataTypeAttribute(typeof(Employee.EmployeeMetadata))]
[MultiColumnSearch(
    "LastName", 
    "FirstName", 
    "Address", 
    "City", 
    "Country")]
public partial class Employee
{
    internal sealed class EmployeeMetadata
    {
        //...
    }
}

[MetadataTypeAttribute(typeof(Order.OrderMetadata))]
[MultiColumnSearch(
    "Employee.LastName", 
    "Employee.FirstName", 
    "Customer.CompanyName", 
    "Customer.ContactName", 
    "Shipper.CompanyName")]
public partial class Order
{
    internal sealed class OrderMetadata
    {
        //...
    }
}

Listing 2 – sample metadata

Figure 2 – cross entity search

Adding UI Mark-Up

I have added the multi column search UI in between the validators and the QueryableFilterRepeater see Listing 3

<asp:DynamicValidator runat="server" ID="GridViewValidator" ControlToValidate="GridView1"
    Display="None" CssClass="DDValidator" />

<fieldset id="MultiSearchFieldSet" class="DD" runat="server" visible="false">
    <legend>Full Text Search</legend>
    <asp:TextBox ID="txbMultiColumnSearch" CssClass="DDTextBox" runat="server" />
    <asp:Button ID="btnMultiColumnSearchSubmit" CssClass="DDControl" runat="server" Text="Search"
        OnClick="btnMultiColumnSearch_Click" />
    <asp:Button ID="btnMultiColumnSearchClear" CssClass="DDControl" runat="server" Text="Clear"
        OnClick="btnMultiColumnSearch_Click" />
</fieldset>
<br />

<asp:QueryableFilterRepeater runat="server" ID="FilterRepeater">

Listing 3 – Multi Column Search UI

Code to wire up the UI and QueryExtender

/// <summary>
/// Setups the multi column search.
/// </summary>
private void SetupMultiColumnSearch()
{
    // get multi column search attribute
    var multiColumnSearch = table.GetAttribute<MultiColumnSearchAttribute>();

    if (multiColumnSearch != null)
    {
        var searchExpression = new SearchExpression()
            {
                DataFields = multiColumnSearch.Columns.ToCsvString(),
                SearchType = SearchType.Contains
            };
        
        // create control parameter
        var controlParameter = new ControlParameter() { ControlID = txbMultiColumnSearch.ID };
        
        // add control parameter to search expression
        searchExpression.Parameters.Add(controlParameter);

        // set context
        searchExpression.SetContext(GridQueryExtender, Context, GridDataSource);

        // add search expression to query extender
        GridQueryExtender.Expressions.Add(searchExpression);

        // make multicolumn search field set visible
        MultiSearchFieldSet.Visible = true;
    }
}

Listing 5 – SetupMultiColumnSearch method

In Listing 5 (which is called from the Page_Init method) we get the attribute and the SearchExpression the if both are not null we add the fields to the SearchExpressions DataFileds property, then we make the whole thing visible.

Note: Much thanks to David Ebbo who sorted out the issue I had had with adding the search expression in code rather than declaratively.

protected void btnMultiColumnSearch_Click(object sender, EventArgs e)
{
    var button = (Button)sender;
    if (button.ID == btnMultiColumnSearchClear.ID)
        txbMultiColumnSearch.Text = String.Empty;
}

Listing 6 – button event

And lastly we need an event to fire when the clear button is fired.

Note: I have both buttons wired-up to this handler as I also add session history here so that when you search on something and go to another page when you return you get the same search, but I also want it cleared if I click the clear button.

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Filter History for Dynamic Data 4

I did a AJAX History in a Dynamic Data Website article back in February 2009 to make filter respect the back button in the browser, this however was not enough for my customers they wanted the filter to be remembered even when they came back to the page without using the back button.

So I decided to store the filter info in Session state for this sample sample (but you could also use a database I have where the client wanted the filters to be remembered across sessions and by user).

I’m adding this extension to the previous sample from Five Cool Filters for Dynamic Data 4 (which now has a couple more filters added) to give history across all the filters.

Extension Methods

So to the code there are two extension methods for this sample AddFilterValueToSession which you can guess adds a filters current value to session and GetFilterValuesFromSession which retrieves an Dictionary of values for the specified table.

/// <summary>
/// Adds the filters current value to the session.
/// </summary>
/// <param name="page">The page.</param>
/// <param name="column">The column.</param>
/// <param name="value">The value.</param>
public static void AddFilterValueToSession(this Page page, MetaColumn column, Object value)
{
    Dictionary<String, Object> filterValues;
    var objectName = column.Table.DataContextPropertyName;

    // get correct column name 
    var columnName = column.Name;
    if (column is MetaForeignKeyColumn)
        columnName = ((MetaForeignKeyColumn)column).ForeignKeyNames.ToCommaSeparatedString();

    // check to see if we already have a session object
    if (page.Session[objectName] != null)
        filterValues = (Dictionary<String, Object>)page.Session[objectName];
    else
        filterValues = new Dictionary<String, Object>();

    // add new filter value to session object
    if (filterValues.Keys.Contains(columnName))
        filterValues[columnName] = value;
    else
        filterValues.Add(columnName, value);

    // add back to session
    if (page.Session[objectName] != null)
        page.Session[objectName] = filterValues;
    else
        page.Session.Add(objectName, filterValues);
}

Listing 1 – AddFilterValueToSession

If you follow the code and comments you will see that first we try to get the session object for this table from session and if it is not there we simply create one. Then we add/update the value for this column and finally save back to session.

Note: that Listing 1 uses an extension method ToCommaSeperatedString() this just simplifies the code for us by removing reusable code.

Updated: As ValZ posted in the comments I have updated the GetFilterValuesFromSession extension method to make sure any links from other List pages are honoured, for instance if you go to the Suppliers page and click on View Products link but already have a filter value that will now be honoured. I’ve also used IDictionary so we don’t have to cast the default values that are passed in.

/// <summary>
/// Gets the filter values from session.
/// </summary>
/// <param name="page">The page.</param>
/// <param name="table">The table.</param>
/// <param name="defaultValues">The default values.</param>
/// <returns>An IDictionary of filter values from the session.</returns>
public static IDictionary<String, Object> GetFilterValuesFromSession(this Page page, 
    MetaTable table, 
    IDictionary<String, Object> defaultValues)
{
    var queryString = new StringBuilder();
    var objectName = table.DataContextPropertyName;
    if (page.Session[objectName] != null)
    {
        var sessionFilterValues = new Dictionary<String, Object>((Dictionary<String, Object>)page.Session[objectName]);
        foreach (string key in defaultValues.Keys)
        {
            if (!sessionFilterValues.Keys.Contains(key) || sessionFilterValues[key] == null)
                sessionFilterValues.Add(key, defaultValues[key]);
            else
                sessionFilterValues[key] = defaultValues[key];
        }
        var t = (Dictionary<String, Object>)page.Session[objectName];
        return sessionFilterValues;
    }
    else
        return defaultValues;
}

Listing 2 – GetFilterValuesFromSession

In Listing 2 we simply get the Dictionary object back from session and then return it.

Applying to the Filters

Listing 3 is a for the ForeignKey filter, here call the AddFilterValueToSession extension method passing in the Column and value from the DropdownList.

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
    OnFilterChanged();
    Page.AddFilterValueToSession(Column, DropDownList1.SelectedValue);
}

Listing 3 – ForeignKey filter

Every filter in that sample has this applied and there are several different examples in there.

Extracting the Filter Values

Now all we need is to get the values and pass them back to the filters each time we arrive at a List page. In Listing 4 I have updated the Page_Init method,  I first attempt to get the filter values from session if none are found I fall back to default List page behaviour.

protected void Page_Init(object sender, EventArgs e)
{
    table = DynamicDataRouteHandler.GetRequestMetaTable(Context);

    var defaultValues = Page.GetFilterValuesFromSession(table, table.GetColumnValuesFromRoute(Context));
    GridView1.SetMetaTable(table, defaultValues);

    GridDataSource.EntityTypeFilter = table.EntityType.Name;
}

Listing 4 – Updating the List page

Now if we switch back to the ForeignKey filter and the Page_Init method Listing 5 you will see that I have not had to change anything here, because we are adding the default values in the List page they will arrive in each filter via the DefaultValue property.

protected void Page_Init(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        if (!Column.IsRequired)
        {
            DropDownList1.Items.Add(new ListItem("[Not Set]", NullValueString));
        }
        PopulateListControl(DropDownList1);

        // Set the initial value if there is one
        string initialValue = DefaultValue;
        if (!String.IsNullOrEmpty(initialValue))
        {
            DropDownList1.SelectedValue = initialValue;
            // optional add auto filters to history
            Page.AddFilterValueToSession(Column, initialValue);
        }
    }
}

Listing 5 – updating the filter

Updated: I’ve also added a optional Page.AddFilterValueToSession(Column, initialValue); to each filter so that filter values passed in in query string can be added to history, NOTE: I’ve only added this to the ForeignKey filter so it’s easy to remove if not required.

I’ll show one complex example of setting up the values in a filter, we will look at me DateRange filter for this. First look at Listing 6 here I am concatenating both values together separated by ‘|’.

protected void btnRangeButton_Click(object sender, EventArgs e)
{
    var button = (Button)sender;
    if (button.ID == btnClear.ID)
    {
        txbDateFrom.Text = String.Empty;
        txbDateTo.Text = String.Empty;
    }
    OnFilterChanged();
    Page.AddFilterValueToSession(Column, String.Format("{0}|{1}", txbDateFrom.Text, txbDateTo.Text));
}

Listing 6 – DateRange button click event

Then if you look at the DateRange filters Page_Init method all need to do is check I have a value, reveres the concatenation and put the values in the correct textboxes.

protected void Page_Init(object sender, EventArgs e)
{
    // set correct date time format
    txbDateFrom_CalendarExtender.Format = DATE_FORMAT;
    txbDateTo_CalendarExtender.Format = DATE_FORMAT;

    if (!Column.ColumnType.Equals(typeof(DateTime)))
        throw new InvalidOperationException(String.Format("A date range filter was loaded for column '{0}' but the column has an incompatible type '{1}'.",
            Column.Name, Column.ColumnType));

    if (DefaultValue != null)
    {
        var values = DefaultValue.Split(new char[] { '|' });
        if (values.Length == 2)
        {
            txbDateFrom.Text = values[0];
            txbDateTo.Text = values[1];
        }
    }
}

Listing 7 – DateRange Page_Init method

Updated: Add clear filters button to clear all filters for a table.

Clear Filters

Last we add a button to clear the filters

<div class="DD">
    <asp:ValidationSummary ID="ValidationSummary1" runat="server" EnableClientScript="true"
        HeaderText="List of validation errors" CssClass="DDValidator" />
    <asp:DynamicValidator runat="server" ID="GridViewValidator" ControlToValidate="GridView1"
        Display="None" CssClass="DDValidator" />
    <asp:QueryableFilterRepeater runat="server" ID="FilterRepeater">
        <ItemTemplate>
            <asp:Label runat="server" Text='<%# Eval("DisplayName") %>' OnPreRender="Label_PreRender" />
            <asp:DynamicFilter runat="server" ID="DynamicFilter" OnFilterChanged="DynamicFilter_FilterChanged" />
            <br />
        </ItemTemplate>
    </asp:QueryableFilterRepeater>
    <asp:Button 
        ID="ClearFiltersButton" 
        runat="server" 
        Text="Clear Filters" 
        CssClass="DDControl"
        OnClick="ClearFiltersButton_Click" />
    <br />
</div>

Listing 8 – Clear filters button

and in the post back of the button

protected void ClearFiltersButton_Click(object sender, EventArgs e)
{
    Page.ClearTableFilters(table);
    Response.Redirect(table.ListActionPath);
}

Listing 9 – Clears filters button method

and lastly we need the method the clears the filters for us,

public static void ClearTableFilters(this Page page, MetaTable table)
{
    var objectName = table.DataContextPropertyName;

    if (page.Session[objectName] != null)
        page.Session[objectName] = null;
}

Listing 10 – Clear filters extension method

Lastly we will need to hide the button when there are no filters.

protected override void OnPreRenderComplete(EventArgs e)
{
    RouteValueDictionary routeValues = new RouteValueDictionary(GridView1.GetDefaultValues());
    InsertHyperLink.NavigateUrl = table.GetActionPath(PageAction.Insert, routeValues);
    if (FilterRepeater.Controls.Count == 0)
        ClearFiltersButton.Visible = false;
    base.OnPreRenderComplete(e);
}

Listing 11 – hiding the clear filters button

So then all done then.

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This minor release includes various bug fixes and enhancements:

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Five Cool Filters for Dynamic Data 4

Starting with the Range Autocomplete, Range & MultiForeignKey Filters from the old Dynamic Data Preview 4 Refresh, I have also added five of my filters:

1. DateRange
2. StartsWith
3. EndsWith
4. Contains
5. Where

I won’t go into much detail here as Oleg Sych has done this great series on DD4 filters, that pretty much explains it all for you.

• Understanding ASP.NET Dynamic Data: Filter Templates
• Extending ASP.NET Dynamic Data: Filtering with Joins
• Understanding ASP.NET Dynamic Data: Entity Templates

I am using the Ajax Control Toolkit for the date picker in the DateRange filter but other than that it’s not much different form the Range filter from the Dynamic Data Preview 4 Refresh sample.

!Important: One thing I would like to point out is that both Entity Framework and Linq to SQL have a small but important issue. This issue is the the “Contains” Expression used in the above filter of the same name is actually expressed as the “Like ‘%{0}%’” and so you DO NOT get full text search using “Contains”.

“Contains” when it was introduced in SQL Server 7 was given a big build up and to be omitted in EF and L2S is a big let down.

Some examples:

Figure 1 – DateRange, StartsWith, EndsWith, Contains, Where and AutoComplete filters

Figure 2 – Range and Multi Select Filters

I just thought that these filters would be useful for your tool boxes.

!Important: I can’t take credit for all the Expression helpers most come from the above mentioned Preview 4 that is no longer on the ASP.Net Codeplex site.

Download

Note I’ve included my five filters and the three filters from the Preview.

As always happy coding.

Making the Text in the DynamicData List Pages GridView Wrap.

Why won’t the text in my Dynamic Data List page GridView wrap? This is answered here and in this post on the ASP.NET Dynamic Data Forum here Re: DynamicField within GridView truncating data where Yuipcheng asks;

“I commented out the code to truncate the FieldValueString, but the rendered text doesn't wrap since the td tag has (style="white-space: nowrap;")”

I answered here but I thought I would document it here also.

Before	After

So you may be asking Dynamic Data 1 didn’t do this, so why does Dynamic Data 4 do it?

The answer it has to do with the validation “*”  showing up next to the field in Edit mode and appears to have just gotten into the GridView as by default we don't do inline editing.

The solution from David Fowler is to create an class and inherit from System.Web.DynamicData.DefaultAutoFieldGenerator and then override the CreateField method, so here it is:

/// <summary>
/// Add the option to the Default Auto Field Generator 
/// to not add the (Style="white-space: nowrap;") to each field.
/// </summary>
public class AdvancedAutoFieldGenerator : DefaultAutoFieldGenerator
{
    private Boolean _noWrap;

    /// <summary>
    /// Initializes a new instance of the 
    /// <see cref="AdvancedAutoFieldGenerator"/> class.
    /// </summary>
    /// <param name="table">The table.</param>
    /// <param name="noWrap">if set to <c>true</c> 
    /// the (Style="white-space: nowrap;") is added 
    /// to each field.</param>
    public AdvancedAutoFieldGenerator(MetaTable table, Boolean noWrap)
        : base(table)
    {
        _noWrap = noWrap;
    }

    protected override DynamicField CreateField(
        MetaColumn column, 
        ContainerType containerType, 
        DataBoundControlMode mode)
    {
        DynamicField field = base.CreateField(column, containerType, mode)

        // override the wrap behavior
        // with the noWrap parameter
        field.ItemStyle.Wrap = !_noWrap;
        return field;
    }
}

Listing 1 – Advanced Field Generator

and we apply it in the Page_Load event of the List page (or you own custom page)

// apply custom auto field generator
GridView1.ColumnsGenerator = new AdvancedAutoFieldGenerator(table, false);

This will then remove the unwanted style,

Note: If you still want this on some pages I have not hard coded it, so you can change it in code where you want to.

A Boolean Date Time Field Template for Dynamic Data 4

Here’s the idea, you want to mark a status of a row with a checkbox and you also need the date time setting one the row to record when the status changed. You normally end up with two fields in your table for this. I decided that in many cases I would only need the date time i.e. if the date time is set then the status has changed is null then not, e.g. to set Order Status to complete set the Complete column to DateTime.Now.

Another reason you may want to use a checkbox to enter a date is to set the date without letting the user enter a custom date.

This turned out to be a little more complicated than I first though and I needed to consult David Ebbo at Microsoft to get the answer. First we’ll deal with the issue I came across that at first was a road block. This is the issue of setting the field to null when the user unchecks the check box.

<%@ Control
    Language="C#" 
    CodeBehind="DateTimeBoolean_Edit.ascx.cs" 
    Inherits="CustomFieldTemplates.DateTimeBoolean_EditField" %>

<asp:CheckBox runat="server" ID="CheckBox1" />
<asp:HiddenField ID="HiddenField1" runat="server" />

Listing 1 – DateTimeBoolean_Edit.ascx

So here in Listing 2 we see the first ExtractValues attempt

protected override void ExtractValues(IOrderedDictionary dictionary)
{
    if (!CheckBox1.Checked)
    {
        // only set to null if unchecked
        dictionary[Column.Name] = String.Empty;
    }
    else if (String.IsNullOrEmpty(HiddenField1.Value))
    {
        // only set a value if there is no current value
        dictionary[Column.Name] = DateTime.Now;
    }
}

Listing 2 – ExtractValues method v1

As you can see if the CheckBox1 is unchecked I set the return value to String.Empty this you would think would do the trick but it doesn't what happens is the value is retained. What confused the matter for me was is if I have a new row or a row with a null value and check it, it sets the value

It turns out that the reason is that the ExtractValues method is called twice the first time when the field template is initialised and the second time when the updated value is returned. But if look at my logic it returns no value the first time the method is called, but a value is required for the system to know that it is to be set to null the second time it is called

So here the full code behind of the Edit template, you will see now that the hidden field is set in the OnDataBound event to make sure we return the correct value the first time ExtractValues is called.

public partial class DateTimeBoolean_EditField : System.Web.DynamicData.FieldTemplateUserControl
{
    protected override void OnDataBinding(EventArgs e)
    {
        base.OnDataBinding(e);

        // keep current value
        HiddenField1.Value = FieldValueString;

        if (FieldValue != null)
            CheckBox1.Checked = true;
        else
            CheckBox1.Checked = false;
    }

    protected override void ExtractValues(IOrderedDictionary dictionary)
    {
        if (!CheckBox1.Checked)
        {
            // only set to null if unchecked
            dictionary[Column.Name] = String.Empty;
        }
        else if (String.IsNullOrEmpty(HiddenField1.Value))
        {
            // only set a value if there is no current value
            dictionary[Column.Name] = DateTime.Now;
        }
        //else
        //    dictionary[Column.Name] = ConvertEditedValue(HiddenField1.Value);
    }

    public override Control DataControl
    {
        get { return CheckBox1; }
    }
}

Listing 3 – DateTimeBoolean_Edit.ascx.cs

And for completeness the read-only version of the field template.

<%@ Control
    Language="C#" 
    CodeBehind="DateTimeBoolean.ascx.cs" 
    Inherits="CustomFieldTemplates.DateTimeBooleanField" %>

<asp:CheckBox ID="CheckBox1" runat="server" Enabled="false" />

Listing 4 – DateTimeBoolean.ascx

public partial class DateTimeBooleanField : System.Web.DynamicData.FieldTemplateUserControl
{
    protected override void OnDataBinding(EventArgs e)
    {
        base.OnDataBinding(e);
        CheckBox1.Checked = !String.IsNullOrEmpty(FieldValueString);
        if (FieldValue != null)
            CheckBox1.ToolTip = FieldValueString;
    }

    public override Control DataControl
    {
        get { return CheckBox1; }
    }
}

Listing 5 – DateTimeBoolean.ascx.cs

You may want to show a date time value instead of the checkbox if so you can just use a copy of the default read-only Date Time field template.

And remember to add a UIHint to set the column to use the new field template

[UIHint("DateTimeBoolean")]
public Nullable<DateTime> ShippedDate { get; set; }

As always happy coding

Conditional Row Highlighting in Dynamic Data

There are occasions when you want to highlight a row in the GridView (I usually want this based on a Boolean field) so here’s what you do.

First of all we need some way of telling the column to do this an I usually use an attribute see Listing 1 it have two properties one for the value when we want the CSS class to be applied, and the other the CSS class to apply.

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, AllowMultiple = false)]
public class RowHighlightingAttribute : Attribute
{
    /// <summary>
    /// Initializes a new instance of the <see cref="RowHighlightingAttribute"/> class.
    /// </summary>
    /// <param name="valueWhenTrue">The value when true.</param>
    /// <param name="cssClass">The CSS class.</param>
    public RowHighlightingAttribute(String valueWhenTrue, String cssClass)
    {
        ValueWhenTrue = valueWhenTrue;
        CssClass = cssClass;
    }

    /// <summary>
    /// Gets or sets the value when true.
    /// </summary>
    /// <value>The value when true.</value>
    public String ValueWhenTrue { get; set; }

    /// <summary>
    /// Gets or sets the CSS class.
    /// </summary>
    /// <value>The CSS class.</value>
    public String CssClass { get; set; }
}

Listing 1 – RowHighlightingAttribute

Next we need a way of applying the CSS class based on the condition, see Listing 2.

/// <summary>
/// Highlights the row.
/// </summary>
/// <param name="fieldTemplate">The field template.</param>
public static void HighlightRow(this FieldTemplateUserControl fieldTemplate)
{
    // get the attribute
    var rowHighlighting = fieldTemplate.MetadataAttributes.GetAttribute<RowHighlightingAttribute>();
    // make sure the attribute is not null
    if (rowHighlighting != null)
    {
        // get the GridViewRow, note this will not
        // be present in a DetailsView.
        var parentRow = fieldTemplate.GetContainerControl<GridViewRow>();
        if (parentRow != null 
            && rowHighlighting.ValueWhenTrue == fieldTemplate.FieldValueString)
        {
            // apply the CSS class appending if a class is already applied.
            if (String.IsNullOrWhiteSpace(parentRow.CssClass))
                parentRow.CssClass += " " + rowHighlighting.CssClass;
            else
                parentRow.CssClass = rowHighlighting.CssClass;
        }
    }
}

Listing 2 – HighlightRow extension method

Now to add the extension method to a field template, we will apply it to the Boolean read-only field template.

protected override void OnDataBinding(EventArgs e)
{
    base.OnDataBinding(e);

    object val = FieldValue;
    if (val != null)
        CheckBox1.Checked = (bool)val;

    // apply highlighting
    this.HighlightRow();
}

Listing 3 – Apply highlighting.

For the sample I’ve also added it to the Text.ascx.cs field template.

Adding some attributes

Figure 1 - Metadata applied

You could also us this technique on other values, but this will do for this sample.

Figure 2 – Row Highlighting applied.

So you can see with a little bit of work you can add conditional row level highlighting to Dynamic Data.

Download

Using Entity Framework from a different DLL in Dynamic Data

I just thought I should document what we learned in this thread here Entity Framework: Entity Model in a separated DLL first of all it is easy to do in Dynamic Data 4 and needs a fix on each page for Dynamic Data 1 (this version that shipped with Visual Studio 2008 SP1 and .Net 3.5 SP1)

Note: see also Rick Andersons blog post here Explicit connection string for EF and L2S

Adding Model from DLL or Class Library

Figure 1 – sample project with Model in Class Library

To use the Northwind Model in our project we need to get a new instance of the Northwind context, to do this we could add the code to instantiate it in the Glabal.asax.cs file. But for me the object of having it in an external class library/DLL is to keep it reusable, so I had the idea of building the connection string in the external class library rather than locally. We add Listing 1 to the class library, as a partial class of the NorthwindEntities class, pass-in the server name (we could pass-in more but the server name will do here).

public partial class NorthwindEntities
{
    /// <summary>
    /// Gets a new NorthwindEntities object.
    /// </summary>
    public static ObjectContext GetContext(String server, String database)
    {
        EntityConnectionStringBuilder entityBuilder = new EntityConnectionStringBuilder();
        entityBuilder.Provider = "System.Data.SqlClient";
        entityBuilder.ProviderConnectionString =
            String.Format("server={0};database={1};Integrated Security=SSPI;MultipleActiveResultSets=True",
            server,
            database);
        entityBuilder.Metadata = @"res://*";
        var objContext = new NorthwindContext.NorthwindEntities(entityBuilder.ToString());

        return objContext;
    }
}

Listing 1 – GetContext helper method

So now all we need to add this to our Dynamic Data app is use this in the RegisterContext method in the Global.asax.cs

DefaultModel.RegisterContext(() => NorthwindContext.NorthwindEntities.GetContext("aragorn","Northwind"),
            new ContextConfiguration()
            {
                ScaffoldAllTables = true
            });

Listing 2 – Using the GetContext helper

Fixing it up to work in Original version of Dynamic Data

This work beautifully in Dynamic Data 4, but not in the previous release we need the fix mentioned in Rick Andersons post

GridDataSource.ContextCreating += delegate(object ceSender,
    EntityDataSourceContextCreatingEventArgs ceArgs)
    {
        ceArgs.Context = (ObjectContext)table.CreateContext();
    };

Listing 3 – Fix for Dynamic Data 1

Added to the List page it looks like this:

protected void Page_Init(object sender, EventArgs e)
{
    DynamicDataManager1.RegisterControl(GridView1, true /*setSelectionFromUrl*/);
    GridDataSource.ContextCreating += delegate(object ceSender,
        EntityDataSourceContextCreatingEventArgs ceArgs)
        {
            ceArgs.Context = (ObjectContext)table.CreateContext();
        };
}

Listing 4 – Added to List page template

You have to add this to each page template and add it twice on the ListDetails page template.

Using Entity Framework Code First (CTP4) in Dynamic Data

Following the sample EF CTP4 Walkthrough: Productivity Improvements you end up with a sample DbContext and of course I immediately thought of using this in Dynamic Data using the “ASP.NET Dynamic Data Entities Web Application” template (Figure 1),

Figure 1 - Select ASP.NET Dynamic Data Entities Web Application

but I got the following error:

Figure 2 – Error when using DbContext with DD4 EF Template.

This my my default code Listing 1

DefaultModel.RegisterContext(typeof(Models.ProductCatalog),
    new ContextConfiguration()
    {
        ScaffoldAllTables = true
    });

Listing 1 – my default DbContext registration

So I fired off an e-mail to Microsoft and was told “the guideline will be to use DD with DomainService, which will have full support of DbContext in the future” although that wont work out of the box at the moment so, I gave up

Then Diego Vega posted on twitter a link to Rowan Millers blog EF CTP4 Tips & Tricks: WCF Data Service on DbContext this turned out to be very useful, he talks about getting the underlying ObjectContext see Listing 2.

public class ProductCatalog : DbContext
{
    public ProductCatalog(String connectionString)
    {
        // set default connection string
        this.Database.Connection.ConnectionString = connectionString;
    }

    public ObjectContext UnderlyingContext
    {
        get { return this.ObjectContext; }
    }

    public DbSet<Category> Categories { get; set; }
    public DbSet<Product> Products { get; set; }
}

public class Category
{
    public string CategoryId { get; set; }
    public string Name { get; set; }

    public virtual ICollection<Product> Products { get; set; }
}

public class Product
{
    public int ProductId { get; set; }
    public string Name { get; set; }
    public string CategoryId { get; set; }

    public virtual Category Category { get; set; }
}

Listing 2 – my ProductCatalog

In Listing 2 I use this feature to get the underlying ObjectContext (Also note my setting the connection string in the constructor). So now we have a cool way of getting Entity Framework Code First CTP4 working with Dynamic Data 4. This makes me very happy

So you will see that all we need to do to get this working with Dynamic Data now is to replace the

typeof(Models.ProductCatalog)

with

() => new Models.ProductCatalog(connectionString).UnderlyingContext

in the RegisterContext method to get at the underlying ObjectContext, which now leads us to Listing 3 .

public static void RegisterRoutes(RouteCollection routes)
{
    var connectionString = "Data Source=aragorn;Initial Catalog=ProductCatalog;Integrated Security=True";
    DefaultModel.RegisterContext(() => new Models.ProductCatalog(connectionString).UnderlyingContext,
        new ContextConfiguration()
        {
            ScaffoldAllTables = true
        });

    routes.Add(new DynamicDataRoute("{table}/{action}.aspx")
    {
        Constraints = new RouteValueDictionary(new { action = "List|Details|Edit|Insert" }),
        Model = DefaultModel
    });
}

Listing 3 – Global.asax RegisterRoutes method.

Now we can Edit, Update and Insert using Entity Framework Code First feature in CTP4.

Download

Nice: One of my favourite things about this is deployment of the DB is that if the DB does not exist on the server specified in the connection string the Entity Framework CTP4 will create it for you (or if you did not specify a connection string it will try to create it in the local SQL Express instance.

!Important: CTP5 make some minor API changes see Dabid Ebbo’s article here Using Dynamic Data with EF Code First and NuGet

Autocomplete Filter from the old Futures project working in Dynamic Data 4

I was sorry that the Autocomplete filter from the old Futures project was not added to Dynamic Data 4 So I thought I would do it, so here it is. I also thought I would make it work with the Entity Framework as well.

First of all if you don’t have a copy of the old futures project then go get it from here Dynamic Data Futures VS2008 SP1 RTM this has many useful samples that are worth adapting to DD4.

Copying The Necessary Files

First we need to copy some filed from the old Futures project to the new project in Visual Studio 2010, see Figure 1 for the files we need and Figure 2 for the where we need to copy them

 Figure 1 - Required files from old Futures project

Figure 2 - Files Added to Custom Filters project

The Files will now need updating to work with this project.

Change namespace in each file

For this I usually just do a global replace in entire project

Figure 3 - Ctrl+H  “Find and Replace”

Remove redundant using

In the Autocomplete.ascx.cs file remove the redundant using statement for Microsoft.Web.DynamicData.

Fix up the AutocompleteFilter.asmx.cs service.

First we need to add some references:

Download and add a reference to Ajax Control Toolkit,

Next we need is to add the using for generic collections;

using System.Collections.Generic;

Then we need to change this;

 return queryable.Cast<object>().Select(row => CreateAutoCompleteItem(table, row)).ToArray();

for this;

var values = new List<String>();
foreach (var row in queryable)
{
    values.Add( CreateAutoCompleteItem(table, row));
}

return values.ToArray(); 

This also makes it compatible with the Entity Framework

Fix up the Autocomplete filter it’s self.

The very first thing is the filter needs to inherit from “System.Web.DynamicData.QueryableFilterUserControl”

public partial class Autocomplete_Filter : System.Web.DynamicData.QueryableFilterUserControl

Add the following Usings:

using System.Web.UI;
using System.Collections;

Then we need to add some properties;

private new MetaForeignKeyColumn Column
{
    get { return (MetaForeignKeyColumn)base.Column; }
}

public override Control FilterControl
{
    get { return AutocompleteTextBox; }
}

Next replace ALL  occurrences of InitialValue with DefaultValue

In the CleantButton_Click event add OnFilterChanged() call

public void ClearButton_Click(object sender, EventArgs e)
{
    // this would probably be better handled using client JavaScirpt
    AutocompleteValue.Value = String.Empty;
    AutocompleteTextBox.Text = String.Empty;
    OnFilterChanged();
}

Remove the SelectedValue property and add the following event handler and method.

protected void AutocompleteValue_ValueChanged(object sender, EventArgs e)
{
    OnFilterChanged();
}

public override IQueryable GetQueryable(IQueryable source)
{
    string selectedValue = String.IsNullOrEmpty(AutocompleteValue.Value) ? null : AutocompleteValue.Value
    if (String.IsNullOrEmpty(selectedValue))
        return source;

    IDictionary dict = new Hashtable();
    Column.ExtractForeignKey(dict, selectedValue);
    foreach (DictionaryEntry entry in dict)
    {
        string key = (string)entry.Key;
        if (DefaultValues != null)
            DefaultValues[key] = entry.Value;

        source = ApplyEqualityFilter(source, Column.GetFilterExpression(key), entry.Value);
    }
    return source;
}

Listing 1 – New Methods for Autocomplete filter.

Next we need to hook-up the HiddenField’s OnValueChanged event handler to point to AutocompleteValue_ValueChanged method we just added, so it looks like this.

<asp:HiddenField
    runat="server" 
    ID="AutocompleteValue" 
    OnValueChanged="AutocompleteValue_ValueChanged"/>

Add a link to the Autocomplete css

Open site.master and drag the AutocompleteStyle.css to the Head section

<link href="AutocompleteStyle.css" rel="stylesheet" type="text/css" />

Now we need to add some styling to the Autocomplete.ascx filter, I’m just adding

CssClass="DDControl"

to the TextBox and Button controls.

Add some Metadata

In Listing 1 we have added a FilterUIHint setting the Autocomplete filter as the the filter for the Orders Customer property.

[MetadataTypeAttribute(typeof(Order.OrderMetadata))]
public partial class Order
{
    internal sealed class OrderMetadata
    {
        [FilterUIHint("Autocomplete")]
        public Customer Customer { get; set; }
    }
}

Listing 3 -  sample metadata

You should now have a working sample run it up and go to the Orders table list page:

Figure 4 - Autocomplete filter in action

Downloads

Happy Coding

EF CTP4 Released!

Entity Framework Code First CTP4 is now available see following links:

• ADO.NET team blog - EF CTP4 Released!
• Microsoft ADO.NET Entity Framework Feature Community Technology Preview 4
• EF CTP4 Walkthrough: Productivity Improvements
• EF CTP4 Walkthrough: Code First
• Productivity Improvements for the Entity Framework
• Conventions for Code First
• Data Annotations in the Entity Framework and Code First
• EF CTP4 Tips & Tricks: Include with Lambda

And a quick note from my testing:

public class ProductCatalog : DbContext
{
    public ProductCatalog()
    {
        this.Database.Connection.ConnectionString =
           "Data Source=.;Initial Catalog=ProductCatalog;Integrated Security=True";
    }

    public DbSet<Category> Categories { get; set; }
    public DbSet<Product> Products { get; set; }
}

Above is from the first sample you create in VS2010 with EF Code First, and a quick way to create your DB on a different server than on localhost\SQLEXPRESS thought this is super cool.