Dynamic Data and Advanced Field Templates - ParentFormView with Templates

• The Anatomy of a FieldTemplate.
• Your First FieldTemplate.
• An Advanced FieldTemplate.
• A Second Advanced FieldTemplate.
• An Advanced FieldTemplate with a GridView ***UPDATED ***.
• An Advanced FieldTemplate with a DetailsView ***UPDATED ***.
• An Advanced FieldTemplate with a GridView/DetailsView Project ***UPDATED ***.
• ParentFormView with Templates ***UPDATED ***.

ParentFormView with Templates

This is a variant on the DetailsView/ParentDetails FieldTemplate the main difference is that here the FieldTemplate is based on a FormView not a DetailsView.

<asp:FormView 
    ID="FormView1" 
    runat="server" 
    DataSourceID="FormDataSource"
    CssClass="detailstable"
    FieldHeaderStyle-CssClass="bold">
    
</asp:FormView>

<asp:LinqDataSource 
    ID="FormDataSource" 
    runat="server" 
    EnableDelete="true">
</asp:LinqDataSource>

Listing 1 – changes to the FieldTemplate

In Listing 1 the DetilsView has been changed to a FormView. All references to DetailsView1 and DetailsDataSource have been changed to FormView1 and FormDataSource in the ascx page and the code behind.

if (metaForeignKeyColumn != null)
{
    // load Field Template
    String ddFolderVirtualPath = metaForeignKeyColumn.ParentTable.Model.DynamicDataFolderVirtualPath;
    String tableName = metaForeignKeyColumn.ParentTable.Name;

    String itemTemplate = ddFolderVirtualPath + "Templates/" + tableName + "Item.ascx";
    String editItemTemplate = ddFolderVirtualPath + "Templates/" + tableName + "Edit.ascx";
    //String insertItemTemplate = ddFolderVirtualPath + "Templates/" + tableName + "Insert.ascx";
    String footerTemplate = ddFolderVirtualPath + "Templates/" + tableName + "Footer.ascx";
    String headerTemplate = ddFolderVirtualPath + "Templates/" + tableName + "Header.ascx";
    String pagerTemplate = ddFolderVirtualPath + "Templates/" + tableName + "Pager.ascx";

    if (File.Exists(Server.MapPath(itemTemplate)))
    {
        FormView1.ItemTemplate = LoadTemplate(itemTemplate);

        // load any other field templates
        //TODO: if an operation is required but no template throw error
        if (File.Exists(Server.MapPath(editItemTemplate)))
            FormView1.EditItemTemplate = LoadTemplate(editItemTemplate);

        // because this is a parent no insert will be available
        //if (File.Exists(Server.MapPath(insertItemTemplate))) 
        //    FormView1.InsertItemTemplate = LoadTemplate(insertItemTemplate);

        if (File.Exists(Server.MapPath(footerTemplate)))
            FormView1.FooterTemplate = LoadTemplate(footerTemplate);
        if (File.Exists(Server.MapPath(headerTemplate)))
            FormView1.HeaderTemplate = LoadTemplate(headerTemplate);
        if (File.Exists(Server.MapPath(pagerTemplate)))
            FormView1.PagerTemplate = LoadTemplate(pagerTemplate);

        ...//CODE OMITTED FOR CLARITY
    }
    else
    {
        throw new InvalidOperationException("ParentFormView_Edit requires an item template.");
    }
}
else
{
    // throw an error if set on column other than MetaChildrenColumns
    throw new InvalidOperationException("The GridView FieldTemplate can only be used with MetaChildrenColumns");
}

Listing 2 – changes to the code behind

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

    // get the FK column
    var metaForeignKeyColumn = Column as MetaForeignKeyColumn;

    // get the association attributes associated with MetaChildrenColumns
    var association = metaForeignKeyColumn.Attributes.
        OfType<System.Data.Linq.Mapping.AssociationAttribute>().FirstOrDefault();

    if (metaForeignKeyColumn != null && association != null)
    {
        // get keys ThisKey and OtherKey into dictionary
        var keys = new Dictionary<String, String>();
        var seperator = new char[] { ',' };
        var thisKeys = association.ThisKey.Split(seperator);
        var otherKeys = association.OtherKey.Split(seperator);
        for (int i = 0; i < thisKeys.Length; i++)
        {
            keys.Add(thisKeys[i], otherKeys[i]);
        }

        // setup the where clause 
        // support composite foreign keys
        foreach (String fkName in metaForeignKeyColumn.ForeignKeyNames)
        {
            // get the current FK column
            var fkColumn = metaForeignKeyColumn.Table.GetColumn(fkName);
            // get the current PK column
            var pkColumn = metaForeignKeyColumn.ParentTable.GetColumn(keys[fkName]);

            // setup parameter
            var param = new Parameter();
            param.Name = pkColumn.Name;
            param.Type = pkColumn.TypeCode;

            // get the value for this FK column
            param.DefaultValue = GetColumnValue(fkColumn).ToString();

            // add the where clause
            FormDataSource.WhereParameters.Add(param);
        }
    }
}

Listing 3 – OnDataBinding now handles multiple PK-FK relationships ***UPDATED 2008/09/24***

As you can see what has been done here add the facility to load templates for the FormView to allow this I’ve added a new folder to the DynamicData folder named Templates see Figure 1.

Figure 1 - Folder structure changes

In Listing 2 you can see that Model.DynamicDataFolderVirtualPath is accessed to retrieve the Dynamic Data virtual path (the default is ~/DynamicData/) so that the path to each Template can be constructed. The path to each of the possible Templates is constructed, but only the itemTemplate is required.

Note: Code to test for other Templates could be added if that option was enabled via properties set via the constructor.

All you need to create a Template file is to add a new UserControl to the Templates folder and then customise it.

<p class="droplist">
<strong>Name: </strong><asp:DynamicControl ID="DynamicControl1" runat="server" DataField="CompanyName" ></asp:DynamicControl>&nbsp;
<strong>Contact Name: </strong><asp:DynamicControl ID="DynamicControl2" runat="server" DataField="ContactName" ></asp:DynamicControl>
</p>
<p class="droplist">
<strong>Phone: </strong><asp:DynamicControl ID="DynamicControl3" runat="server" DataField="Phone" ></asp:DynamicControl>&nbsp;
<strong>Fax: </strong><asp:DynamicControl ID="DynamicControl4" runat="server" DataField="Fax" ></asp:DynamicControl>
</p>

Listing 4 – a very simple ItemTemplate

As you can see Listing 4 is a very simple field template but looks how you would expect the mark-up to look in Figure 2.

Figure 2 – the FieldTemplate at work

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