checkbox added in gridview

. right click on your DataGrid -->Property Builder -->Columns --> Template Column --> Apply --> Ok.
2. Right click again --> EidtTemplate --> choose Column you add --> drag CheckBox control from Toolbox and drop it in ItemTemplate field and if you need CheckBox in edit mode put another CheckBox control in EditItemTemplate field --> End Template Editing.

Code on the button:

private void btn_Delete_Click(object sender, System.EventArgs e)
{
for(int i=0;i<dg_EditProduct.Items.Count;i++)
{   
CheckBox chk = new CheckBox();
chk = (CheckBox)dg_EditProduct.Items[i].FindControl("chk_Delete");
if(chk.Checked)
{   
DataTable myTable;
myTable=(DataTable)Session["ProductTable"];
int ID_Delete = Convert.ToInt32( myTable.Rows[i]["ProductID"]);

Str_Conn = ConfigurationSettings.AppSettings["Fashion"];
MyConn = new SqlConnection(Str_Conn);

//Command to delete Product
//     SqlCommand cmd_DeleteProduct = new SqlCommand("dbo.DeleteProduct",MyConn);
SqlCommand cmd_DeleteProduct = new SqlCommand("DeleteProduct",MyConn);
cmd_DeleteProduct.CommandType = CommandType.StoredProcedure;
SqlParameter ProductID_Delete = cmd_DeleteProduct.Parameters.Add("@ProductID",SqlDbType.Int);
ProductID_Delete.Value = ID_Delete ;

MyConn.Open();
dg_EditProduct.DataSource = myTable;
cmd_DeleteProduct.ExecuteNonQuery();
MyConn.Close();
}
}
BindData(); // it is the function you use to bind data to datagrid on page load
}