title: Specify an item placeholder by setting a control's ID property to "itemPlaceholder"
body: <p>I have only single "Default.aspx" page and a single ListView Control. Why am I getting this error. Never Happened before</p>
  
  <p>"An item placeholder must be specified on ListView 'ListView1'. Specify an item placeholder by setting a control's ID property to "itemPlaceholder". The item placeholder control must also specify runat="server"."</p>
  
  <pre><code>&lt;%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="TesterConcepts._Default"%&gt;
  
      &lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;
  
      &lt;html xmlns="http://www.w3.org/1999/xhtml" &gt;
      &lt;head runat="server"&gt;
          &lt;title&gt;&lt;/title&gt;
      &lt;/head&gt;
      &lt;body&gt;
          &lt;form id="form1" runat="server"&gt;
          &lt;div&gt;
  
          &lt;/div&gt;
          &lt;asp:ObjectDataSource ID="ObjectDataSource1" runat="server" 
              onselecting="ObjectDataSource1_Selecting" SelectMethod="GetItemsCollection" 
              TypeName="TesterConcepts.CutomDataSource"&gt;
              &lt;SelectParameters&gt;
                  &lt;asp:Parameter Name="items" Type="Object" /&gt;
              &lt;/SelectParameters&gt;
          &lt;/asp:ObjectDataSource&gt;
          &lt;asp:ListView ID="ListView1" runat="server" DataSourceID="ObjectDataSource1" 
              onselectedindexchanged="ListView1_SelectedIndexChanged"&gt;
          &lt;/asp:ListView&gt;    
      &lt;/body&gt;
      &lt;/html&gt;
  </code></pre>
  
  <p>doing this was not helpful even</p>
  
  <pre><code>&lt;asp:ListView ID="ListView1" runat="server" DataSourceID="ObjectDataSource1"
       OnSelectedIndexChanged="ListView1_SelectedIndexChanged"
          ItemPlaceholderID="PlaceHolder1"&gt;
  &lt;/asp:ListView&gt;
  &lt;asp:PlaceHolder ID="PlaceHolder1" runat="server"&gt;&lt;/asp:PlaceHolder&gt;
  </code></pre>
  
  <p>Now it throws this exception</p>
  
  <p>"An item placeholder must be specified on ListView 'ListView1'. Specify an item placeholder by setting a control's ID property to "PlaceHolder1". The item placeholder control must also specify runat="server""</p>