Why is my CommandArgument Empty?
You can't use the <%= %>
syntax inside properties on a tag with a runat="server"
attribute. I'm surprised the code will even run. :)
UPDATE:
You probably want to use the ItemDataBound event on the repeater, find the linkbutton and set the CommandArgument property.
Not very elegant, but here's a VB.NET sample.
Private Sub Repeater1_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.RepeaterItemEventArgs) Handles Repeater1.ItemDataBound
Select Case e.Item.ItemType
Case ListItemType.Item, ListItemType.AlternatingItem
Dim b As LinkButton = e.Item.FindControl("btn")
b.CommandArgument = e.Item.ItemIndex
b.DataBind()
End Select
End Sub