Dynamic Data - Hiding Tables on the Default.aspx page

This is just a write up of an answer to a question on the Dynamic Data forum, so here's the solution.

First of all we need an attribute class:

[AttributeUsage(AttributeTargets.Class)]
public class HideTableInDefaultAttribute : Attribute
{
    public Boolean Hide { get; private set; }

    public HideTableInDefaultAttribute(Boolean hide)
    {
        Hide = hide;
    }
    // this will allow us to have a default set to false
    public static HideTableInDefaultAttribute Default = 
        new HideTableInDefaultAttribute(false);
}

Listing 1 - HideTableIndefaultAttribute

And now the code in the Default.aspx:

protected void Page_Load(object sender, EventArgs e)
{
    System.Collections.IList visibleTables = Global.DefaultModel.VisibleTables;
    if (visibleTables.Count == 0)
        throw new InvalidOperationException(
            @"There are no accessible tables. 
            Make sure that at least one data model is 
            registered in Global.asax and scaffolding is 
            enabled or implement custom pages.");

    //Menu1.DataSource = visibleTables;
    //Menu1.DataBind();

    // Hiding tables
    var tablesMain = (from t in Global.DefaultModel.VisibleTables
                     where !t.Attributes.OfType<HideTableInDefaultAttribute>().
                        DefaultIfEmpty(HideTableInDefaultAttribute.Default).First().Hide
                     orderby t.DisplayName
                     select t).ToList();

    Menu1.DataSource = tablesMain;
    Menu1.DataBind();

}

Listing 2 - Default.aspx Page_Load event handler

Note in the where clause the DefaultIfEmpty which allows you to specify the default value to return if no value found. This means that you will always get a value and the default value will have the Hide property set to false because of the Default keyword in the Attribute definition.

Now some sample metadata:

// note the differance in the result of using 
// ScaffoldTable(false) over HideTableInDefault(true)
[ScaffoldTable(false)]
public partial class Category
{
}

[HideTableInDefault(true)]
public partial class EmployeeTerritory 
{
}

[HideTableInDefault(true)]
public partial class Product
{
}

Listing 3 - sample metadata

Figure 1 - Limited Tables list from Northwind

Figure 2 - See how the Products column has a foreign key link

Figure 3 - Note that the Category column has no link

If you look at each of the above Figures you will see the differences between a ScaffoldTable(false) and a HideTableInDefault(true). It's also worth noting that if you omit a table from the Model you either get a ForeignKey column of no column if it was a children column, so this makes using the above two methods the best way of hiding tables in the Default.aspx page.

Download Project

Note: You will need to change the Connection String in the web.config