Though Your question is not clear i am trying to answer from what i understood...
your link button code in .aspx.cs file should be like...
<asp:linkbutton id="lnkdelete" runat="server" text="Delete" commandname="del" commandargument='<%# Eval("PrimaryKey_ID") %>' >
</asp:linkbutton>
here look at
commandname = "del",
if you use
commandname "delete" or "edit" it will automatically call the
OnRowDeleted or OnRowEdited event
so make sure you are not using this reserved keyword as your commandname otherwise it will call those events and your OnRowCommand Event will not get executed.
AND another thing try to use OnRowCommand
1(){} if this works.
please elaborate your question.
Hope This Help