Select column dissapears in radGrid

[raskarov]

I want to selectively disable checkboxes based on expression. 

I add code to grid prerender to iterate through each GridDataItem and if condition met, I want to disable checkboxes for select column.

my aspx part:

<Columns>
                <telerik:GridClientSelectColumn UniqueName="checkboxColumn">
                </telerik:GridClientSelectColumn>

my code behind

foreach (GridDataItem item in radGrid.MasterTableView.Items)
{
  if (item is GridDataItem)
        {
          for (int i = 1; i < renderedColumns; i++)
            {
                      GridColumn column = radGrid.MasterTableView.RenderColumns[i];
                      Control control = item[column.UniqueName].Controls[0];
                        if (condition==true&&column.uniqueName=="checkboxColumn")
                          {
                     (control as CheckBox).Enabled=false;
                            }

As soon as this code run, the one that had met conditions dissapear from the page, not just getting disabled. 
If I change like:   (control as CheckBox).Enabled=false;  to say: (control as CheckBox).Tooltip="test"; checkboxes also dissapear.

[Shinu]

Hello,

Try the following code in ItemDataBound event.
C#:

protected void RadGrid1_ItemDataBound(object sender, Telerik.Web.UI.GridItemEventArgs e)
{
 if (e.Item is GridDataItem)
 {
   GridDataItem item = (GridDataItem)e.Item;
   CheckBox chk = (CheckBox)item["checkboxColumn"].Controls[0];
   if(condition)
   {
     chk.Enabled = false;
   }
  }
}

-Shinu.

[raskarov]

The same behavior appears when I use the code in ItemDataBound event.