Deleting multiple records in a gridview

I have a gridView which takes data from database and displays it. I have an option for selecting a particular record and then deleting it.
Now I created a option to with CheckBox, for which I can select multiple records and delete them all.
This is my code:
<asp:GridView ID="EmpView" runat="server" AutoGenerateColumns="False"                        onrowcommand="EmpView_RowCommand">                     <Columns>                         <asp:TemplateField HeaderText="Action">              &nbs ...