Using VS 2008, I have a Repeater control:
The best way I found to solve this :
Add the following label anywhere on your page -
Add the OnPreRenderEvent for your Repeater
Now inside this event in your codebehind, write the code
protected void emptyRepeater_PreRender(object sender, EventArgs e)
{
lblEmptyRepeater.Visible = (emptyRepeater.Items.Count==0);
}
Now your empty repeater should be checked after the data is bound but before render on page, and show the label if it is empty.