Gridview FindControl finds Calendar, but not DropDownList

2011-02-04 c# asp.net gridview drop-down-menu findcontrol

I have a DropDownList in a GridView EditItemTemplate. The ddl is to be populated at runtime; options in each row may vary.

The GridView is working as desired. In non-edit mode, it binds to data. In edit mode the controls specified in the EditItemTemplate are rendered.

Question: Why can't I FindControl on this DropDownList??? Note that I can FindControl on a Calendar control that's also in an EditItemTemplate.

Below is the ASPX & C# code.

Thanks!!

<asp:UpdatePanel ID="UpdatePanelSelections" runat="server">
<ContentTemplate>
    <asp:GridView ID="GridViewSelections" runat="server" 
        ...

        <Columns>

            <asp:TemplateField HeaderText="Options" >
                <ItemTemplate>
                    <asp:Label ID="CurrentOption" runat="server" 
                        Text='<%# Eval("Options.OptionName") %>'>
                    </asp:Label>
                </ItemTemplate>

                <EditItemTemplate>
                    <asp:DropDownList ID="ddlOptions" runat="server" >
                    </asp:DropDownList>
                </EditItemTemplate>
                <HeaderStyle HorizontalAlign="Left" />
            </asp:TemplateField>


            <asp:TemplateField HeaderText="Date" >
                <ItemTemplate>
                    <asp:Label ID="CurrentlySelectedDate" runat="server" 
                        Text='<%# Eval("SomeDate") %>'>
                    </asp:Label>
                </ItemTemplate>

                <EditItemTemplate>
                    <asp:Calendar ID="calNewDate" runat="server" SelectedDate='<%# Bind("SomeDate") %>' VisibleDate='<%# Bind("SomeDate") %>' />
                </EditItemTemplate>
                <HeaderStyle HorizontalAlign="Left" />
            </asp:TemplateField>

        ...


    protected void GridViewSelections_RowEditing(object sender, GridViewEditEventArgs e)
   {
    // FindControl calNewDate works in GridViewSelections_RowUpdating but not in GridViewSelections_RowEditing
    Calendar calNewDate = GridViewSelectionss.Rows[e.NewEditIndex].FindControl("calNewDate") as Calendar;

    // FindControl ddlOptions doesn't work anywhere!
    DropDownList ddlOptions = GridViewSelections.Rows[e.NewEditIndex].FindControl("ddlOptions") as DropDownList;

// Looking in Cells doesn't work either
DropDownList ddlOptions2 = GridViewSelections.Rows[e.NewEditIndex].Cells[2].FindControl("ddlOptions") as DropDownList;

Answers

The solution turned out to be checking that the DataItem isn't null. Just checking for RowType and Edit flag wasn't enough.

protected void GridViewSelections_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if ((e.Row.RowType == DataControlRowType.DataRow) && (e.Row.RowState.HasFlag(DataControlRowState.Edit) && (e.Row.DataItem != null)))
    {
        DropDownList ddlOptions = e.Row.FindControl("ddlOptions") as DropDownList;
        ddlOptions.Items.Add(new ListItem("aaa", "1"));
        ddlOptions.Items.Add(new ListItem("bbb", "2"));
        ddlOptions.Items.Add(new ListItem("ccc", "3"));

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