title: Exception "The name 'BindItem' does not exist in the current context"
body: <p>I'm recently found out that you can use "BindItem" and "Item" directly in the markup of an aspx page in the context of databound controls like GridView or DetailsView (by specifying the <code>ItemType</code> attribute). What I'm trying to achieve now is inline comparison of members such as:</p>
  
  <pre><code>    &lt;asp:RadioButton Text="All Assigned" ID="rb1" 
           Checked='&lt;%# BindItem.AllAssigned %&gt;' 
           runat="server" GroupName="AllAssigned" /&gt;
      &lt;asp:RadioButton Text="Responsible only"  ID="rb2" 
           Checked='&lt;%# !BindItem.AllAssigned %&gt;' 
           runat="server" GroupName="AllAssigned" /&gt;
  </code></pre>
  
  <p>In this situation I need Two-Way-Binding, so i choose the BindItem expression.
  But it seems that expressions like <code>!BindItem.AllAssigned</code> or <code>BindItem.AllAssigned == false</code> are not working in Markup. They are giving me exceptions like </p>
  
  <p><strong>The name 'BindItem' does not exist in the current context</strong> </p>
  
  <p>or </p>
  
  <p><strong>DataBinding: DataContext.MyEntity does not contain a property with the name  'false'.</strong></p>
  
  <p>What do I have to write for such expressions?</p>