You forgot the
OnItemCommand
event in Repeater
Remove OnCommand="LinkButton1_Command"
<asp:repeater onitemcommand="RepeaterCommandEventHandler" xmlns:asp="#unknown" />
in your example
<asp:repeater id="Repeater1" runat="server" onitemcommand="Repeater1_ItemCommand">
<itemtemplate>
<asp:linkbutton id="LinkButton1" runat="server" commandname="MyUpdate" commandargument="<%# Eval("CategName") %>">LinkButton</asp:linkbutton>
</itemtemplate></asp:repeater>
in .cs
protected void Repeater1_ItemCommand(object sender, RepeaterCommandEventArgs e)
{
if (e.CommandName == "MyUpdate")
{
}
}