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Hi,

I am trying to write a databound control, SimpleControl, with an ITemplate named ItemViewTemplate. This control exposes a property of type SimpleItem. When this property is set, the controls within the SimpleControl are populated.

This all works fine when I put the control in the aspx file with no ItemViewTemplate markup. Once I put in the ItemViewTemplate markup, I get an error:
Cannot convert type 'System.Web.UI.Control' to 'Controls.Web.SimpleControlTemplate'. 

Below is my code.

Thanks in advance for your help.

SimpleControl.cs
C#
public class SimpleControl : CompositeControl
   {
       ITemplate _ItemViewTemplate = null;
       SimpleControlContainer _ItemContainer;

       [TemplateContainer(typeof(SimpleControlTemplate))]
       [PersistenceMode(PersistenceMode.InnerProperty)]
       public ITemplate ItemViewTemplate
       {
           get { return _ItemViewTemplate; }
           set { _ItemViewTemplate = value; }
       }

       public SimpleItem Item
       {
           get
           {
               if (ViewState["Item"] == null) ViewState["Item"] = new SimpleItem();
               return ViewState["Item"] as SimpleItem;
           }
           set
           {
               ViewState["Item"] = value;
           }
       }

       protected override void CreateChildControls()
       {
           _ItemContainer = new SimpleControlContainer();

           if (this._ItemViewTemplate == null)
           {
               this._ItemViewTemplate = new SimpleControlTemplate(_ItemContainer);
           }

           this._ItemViewTemplate.InstantiateIn(this);
           base.CreateChildControls();
       }
   }

SimpleControlContainer.cs
C#
public sealed class SimpleControlContainer : CompositeControl
{
    TextBox t;
    protected override void CreateChildControls()
    {
        t = new TextBox();
        t.ID = "txt";
        t.DataBinding += new EventHandler(t_DataBinding);

        this.Controls.Add(t);
        base.CreateChildControls();
    }

    void t_DataBinding(object sender, EventArgs e)
    {
        SimpleControl sc = (SimpleControl)this.NamingContainer;
        this.t.Text = sc.Item.Name;
    }
}

SimpleControlTemplate.cs
C#
public sealed class SimpleControlTemplate : ITemplate, INamingContainer
{
    private SimpleControlContainer sContainer;

    public SimpleControlTemplate(SimpleControlContainer container)
    {
        this.sContainer = container;
    }

    public void InstantiateIn(Control container)
    {
        container.Controls.Add(sContainer);
    }
}

SimpleItem.cs
C#
[Serializable]
public class SimpleItem
{
    public string Name { get; set; }
}

View.aspx.cs
C#
public partial class Items_View : System.Web.UI.Page
{
    protected override void OnLoad(EventArgs e)
    {
        this.SimpleControl1.Item.Name = "test";
        this.SimpleControl1.DataBind();
        base.OnLoad(e);
    }
}

View.aspx (this code binds correctly)
C#
<html xmlns="http://www.w3.org/1999/xhtml">
<head  runat="server">
    <title></title>
</head>
<body>
    <form id="form1"  runat="server">
         <cc1:SimpleControl ID="SimpleControl1"  runat="server">
         </cc1:SimpleControl>
    </form>
    </body>
</html>

View.aspx (this code gives me error)
C#
<html xmlns="http://www.w3.org/1999/xhtml">
<head  runat="server">
    <title></title>
</head>
<body>
    <form id="form1"  runat="server">
         <cc1:SimpleControl ID="SimpleControl1"  runat="server">
             <ItemViewTemplate>
                  <asp:TextBox ID="t" runat="server" Text='<%#Eval("Name") %>' />
             </ItemViewTemplate>
         </cc1:SimpleControl>
    </form>
    </body>
</html>
Posted
Updated 6-Jan-12 19:54pm
v2

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