Question

I am writing a Composite control, which contains a listview to display a table of items. Normally when using a ListView in Asp.NET I would define the templates in the code-forward.

<asp:ListView runat='server' ID='ArticleList'>     <LayoutTemplate>         <div class='ContentContainer'>             <div runat='server' id='itemPlaceholder' />         </div>     </LayoutTemplate>     <ItemTemplate>         <div>             <div><%# Eval('Content') %></div>         </div>     </ItemTemplate>     </asp:ListView> 

I assume it’s something like:

ListView view = new ListView(); view.LayoutTemplate = ..... view.ItemTemplate = .....  // when do I call these? view.DataSource = myDataSource; view.DataBind(); 

Update: I created 2 templates by implementing the ITemplate interface:

private class LayoutTemplate : ITemplate {     public void InstantiateIn(Control container)     {         var outer = new HtmlGenericControl('div');         var inner = new HtmlGenericControl('div') { ID = 'itemPlaceholder' };         table.Rows.Add(row);          container.Controls.Add(table);     } }  private class ItemTemplate : ITemplate {     public void InstantiateIn(Control container)     {         var inner = new HtmlGenericControl('div');          container.Controls.Add(inner);     } } 

and I can add them using:

dataList.LayoutTemplate = new LayoutTemplate(); dataList.ItemTemplate = new ItemTemplate(); 

But then I get stuck, since container.DataItem is null.

Answer 1

The trick is to subscribe to the databinding event of the itemplaceholder in the ItemTemplate.

The complete solution:

public class FibonacciControl : CompositeControl {     public FibonacciControl()     {         // ....     }      protected override void CreateChildControls()     {         base.CreateChildControls();          ListView view = new ListView();          view.LayoutTemplate = new LayoutTemplate();         view.ItemTemplate = new ItemTemplate();          view.DataSource = FibonacciSequence();         view.DataBind();          this.Controls.Add(view);     }      private IEnumerable<int> FibonacciSequence()     {          int i1 = 0;         int i2 = 1;          for (int i = 0; i < Iterations; i++)         {             yield return i1 + i2;             int temp = i1 + i2;             i1 = i2;             i2 = temp;         }         yield break;     }      public int Iterations { get; set; }      private class LayoutTemplate : ITemplate     {          public void InstantiateIn(Control container)         {             var ol = new HtmlGenericControl('ol');             var li = new HtmlGenericControl('li') { ID = 'itemPlaceholder' };             ol.Controls.Add(li);              container.Controls.Add(ol);         }     }      private class ItemTemplate : ITemplate     {         public void InstantiateIn(Control container)         {             var li = new HtmlGenericControl('li');              li.DataBinding += DataBinding;             container.Controls.Add(li);         }          public void DataBinding(object sender, EventArgs e)         {             var container = (HtmlGenericControl)sender;             var dataItem = ((ListViewDataItem)container.NamingContainer).DataItem;              container.Controls.Add( new Literal(){Text = dataItem.ToString() });         }     } }