Function in Template field Grid view Label

  <asp:TemplateField HeaderText="Course Level" SortExpression="Course_id">

      <ItemTemplate>

      <asp:Label ID="lbl_crselevel" runat="server" Text='<%#GetLevelName(Eval("Course_id")) %>' ></asp:Label>

      </ItemTemplate>

      </asp:TemplateField>

aspx.cs page code

  public string GetLevelName(object CourseID)

    {

}