GridLookup for ASP.NET Web Forms - How to display a custom text when all rows are selected

This example illustrates how to display a custom text inside ASPxGridLookup when all its rows are selected.

To implement this scenario, follow the steps below:

1. Handle the ASPxGridLookup.ValueChanged event to pass a flag to the client. The flag indicates whether all rows are selected.

   protected void gridLookup_ValueChanged(object sender, EventArgs e)
   {
       ASPxGridLookup gl = sender as ASPxGridLookup;
       if (gl.GridView.Selection.Count == gl.GridView.VisibleRowCount)
           gl.GridView.JSProperties["cp_selected"] = true;
   }

2. On the client, handle the ASPxClientGridLookup.EndCallback event and specify a custom text if the flag returns true.

   function OnEndCallback(s, e) {
       if (s.GetGridView().cp_selected) {
           s.GetInputElement().value = "(Select All)";
           delete (s.GetGridView().cp_selected);
       }
   }

Files to Review

• Default.aspx (VB: Default.aspx)
• Default.aspx.cs (VB: Default.aspx.vb)