This is the most common problem that generally users face while dealing with Repeater control. I gave this solution in Stackoverflow. want to post it here for users coming from search
Add the below snippet in in template
CommandArgument='<%#Eval("ScrapId")+","+ Eval("UserId")%>'
In code behind you can use retrieve values like this
1protected void GridViews_RowCommand(object sender, GridViewCommandEventArgs e) 2{ 3 if (e.CommandName == "Comment") 4 { 5 string[] commandArgs = e.CommandArgument.ToString().Split(new char[] { ',' }); 6 string scrapid = commandArgs[0]; 7 string uid = commandArgs[1]; 8 } 9}