Problems binding DropDownList

[Ana D.]

Hi,

In my page I have a GridView in which I have an Item Template with a label and Edit Template with a DropDownList. Something like this:

<asp:GridView ID="MyGridView" runat="server" OnPageIndexChanging="MyGridView_PageIndexChanging" DataKeyNames="Id" OnRowEditing="MyGridView_RowEditing">
   <Columns>
      <asp:TemplateField HeaderText="Use" ItemStyle-Width="140px" ItemStyle-HorizontalAlign="Center">
         <ItemTemplate>
            <asp:Label ID="UseLabel" runat="server" Text='<%#Eval("ImageUse")%>' />
         </ItemTemplate>
         <EditItemTemplate>
            <asp:DropDownList ID="UseDropDownList" runat="server" OnDataBinding="UseDropDownList_DataBinding" />
         </EditItemTemplate>
      </asp:TemplateField>
   </Columns>
</asp:GridView>

However, in the method UseDropDownList_DataBinding the line

Dim UseDropDownList As DropDownList = ExclusiveHistoryGridView.FindControl("UseDropDownList")

always result nothing. With this, I can't Bind the DropDownList because it's not being found. How do I bind it then?

Thanks in advance for all replies!

Ana

[:Francis:]

AFAIK the reason you aren't finding the DropDownLists is that each DDL get its own unique ID like; DropDownList123555.

You can get the unique IDs by using the GridView's RowDataBound event:

protected void MyGridView_RowDataBound(object sender, System.Web.UI.WebControls.GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            DropDownList DDL = (DropDownList)e.Row.FindControl("UseDropDownList");

            DDL.DataSource = whatever datasource you want;
            
            string uniqueID = DDL.UniqueID; //This is what you need to find the DDL later on.
            
            int rowIndex = int.Parse(e.Row.RowIndex.ToString());
        } 
    }

It shouldn't be too hard to re-write the code to VB :).

Regards

Francis

[QVeen72]

Hi,

To Bind the Dropdown list.. First Write a Function in .vb page (say RetMyTable) which returns a DataTable and Your Edit Item Template should look like this...:

<EditItemTemplate>
<asp:DropDownList ID="DropDownList1" Runat="server"     
DataSource='<%#RetMyTable() %>'
DataTextField="MyFieldName" DataValueField="MyFieldName"
SelectedValue='<%# Bind("MyFieldName") %>' />                        
</EditItemTemplate>

Regards
Veena

[rajalingam22]

you used ado.net with bind the control...

[Ana D.]

I think I didn't express my question clearly. I know how to bind a DropDownList in the code behind. The problem I was having, however, was that, in the ItemTemplate (when the data is only being displayed to the user) I have a Label where the Text is retrieved from the database: Text='<%#Eval("ImageUse")%>'
When the User clicks on Edit Button, this label should be replaced by a DropDownList, which call the myDropDownList_DataBinding. In Protected Sub myDropDownList_DataBound (...) I had: Dim ddl as DropDownList = myGridView.FindControl("myDropDownList"). The problem was: myGridView.FindControl("myDropDownList") = Nothing and this is why I couldn't bind the DropDownList.
The solution was, instead of using myGridView.FindControl("myDropDownList"), use this: Dim myDropDownList as DropDownList = sender (actually, the sender is the DropDownList...) and bind the ddl.

Thanks for all the replies.