DetailsView and dropdownlist

Sandraa

Hi all, i have a little problem that even i don't know like solve. I know that is possible but I don't know how. I have a project ASP.NET with VBasic.NET I want to add a dropdownlist to DetailsView with diferent source that detailsview. I put my code and the error:

                Dim InsertComboUsuarios As DropDownList = DirectCast(detailsView.FindControl("InsertComboUsuarios"), DropDownList)
                Dim UsuariosServicios As New DataTable
                UsuariosServicios = Servicios.ObtenerUsuariosServicios()
                InsertComboUsuarios.DataSource = UsuariosServicios
                InsertComboUsuarios.DataTextField = UsuariosServicios.Columns("Usuario").ColumnName.ToString()
                InsertComboUsuarios.DataValueField = UsuariosServicios.Columns("IdUsuario").ColumnName.ToString()
                InsertComboUsuarios.DataBind()

the code in aspx:

                <asp:TemplateField HeaderText="Usuario del Servicio" >
                 <ItemTemplate>
                    <asp:Label ID="lblUsuario" Text='<%# Eval("Id\_Usuario") %>' runat="server"></asp:Label>
                 </ItemTemplate>
                 <EditItemTemplate>
                    <asp:DropDownList ID="EditComboUsuarios" runat="server"></asp:DropDownList>
                </EditItemTemplate>
                <InsertItemTemplate>
                    <asp:DropDownList ID="InsertComboUsuarios" runat="server"></asp:DropDownList>
                </InsertItemTemplate>
                </asp:TemplateField>

and the error is: System.NullReferenceException was caught Message="Referencia a objeto no establecida como instancia de un objeto." Source="App_Web_ie3hu1zc" The source failed when pass by InsertComboUsuarios.DataSource = UsuariosServicios some idea? thanks very much for your help

Marcelo Emmerich

Hi Sandraa, I have done this many times. I don't know exactly why it does not work for you (did not try it out), however, I want to show you a snippet of my working code. Besides being C# the main difference is that I use declarative syntax only: First the dropdown declaration in the .aspx file: SelectedValue='<%# Bind("fake_flag1")%>' ID="ddl_test1" DataSourceID="TestDS" DataTextField="someDescription" DataValueField="someID" runat="server"> Next the declaration of the datasource for the above dropdown, which is different of the detailsview the dropdown is in: SelectCommand="SELECT * FROM TEST"> Hope this helps. Maybe the problem in your code is the point in time when you try to set the datasource? Cheers, Marcelo

-- Marcelo Emmerich Software Development - Computer Graphics - Mobile Computing http://bytethings.blogspot.com

Sandraa

Thanks Marcelo but your code is for aspx and I am using aspx.vb, I don't know like call well to dropdownlist from aspx.vb page and from detailsview. Remenber that my dropdownlist is into a detailsview :( Thanks for all ;)

Christian Graus

Sandraa wrote:

but your code is for aspx and I am using aspx.vb

Yes, he said you'd have to convert C# to VB, that's trivial to do. Also, he said he's doing it in the aspx, is there any reason you can't try it that way ?

Christian Graus Driven to the arms of OSX by Vista.

Nishant Singh

Hi Sandraa, Are you sure

Dim InsertComboUsuarios As DropDownList = DirectCast(detailsView.FindControl("InsertComboUsuarios"), DropDownList)

This line is returning you a DropDownList object ??? That is to say InsertComboUsuarios is not null ??

Sandraa

I believe that yes, I put you the code in aspx page

                <asp:TemplateField HeaderText="Usuario del Servicio" >
                 <ItemTemplate>
                    <asp:Label ID="lblUsuario" Text='<%# Eval("Id\_Usuario") %>' runat="server"></asp:Label>
                 </ItemTemplate>
                 <EditItemTemplate>
                    <asp:DropDownList ID="EditComboUsuarios" runat="server"></asp:DropDownList>
                </EditItemTemplate>
                <InsertItemTemplate>
                    <asp:DropDownList ID="InsertComboUsuarios" runat="server"></asp:DropDownList>
                </InsertItemTemplate>
                </asp:TemplateField>

I believe that I have put something bad in this code. Thanks for your help.

Sandraa

S.O.S Even I continue with this problem, please any idea?