dropdownlist and gridview

In sql server2005 I have commodity type as int. In dropdownlist I loaded commodity type as string shown in code, when I bind to gridview I got commmodity type as int. I need to have string value in grid and int value in data base, how I can do?

Now I am getting int value in database(right) but int value in grid view also.

  <asp:DropDownList ID="ddlcommodity" runat="server"                    >
                
                   <asp:ListItem Value="0">abc<asp:ListItem>
                   <asp:ListItem Value="1">def</asp:ListItem>
                   <asp:ListItem Value="2">ppp</asp:ListItem>
                   <asp:ListItem Value="3">qqq</asp:ListItem>
               </asp:DropDownList>
  protected void dgvcommodity_RowCommand(object sender, GridViewCommandEventArgs e)
    {        ////  try        ////{        if (e.CommandName == "edit123")
        {            if (btnsave.Text == "Save")            {              
                GridViewRow row = (GridViewRow)((Control)e.CommandSource).NamingContainer;
                              btnsave.Text = "Update";
                 ddlcommodity.SelectedValue = dgvcommodity.DataKeys[row.RowIndex].Values["commodity"].ToString();
               }