ListView find dropdownlist in table

Question

I have a list view with table inside and i need to get all dropdown lists and file upload controls, but find returns nothing. This is my code:

<asp:ListView runat="server" ID="MyListView" OnItemDataBound="FillDropDownList">
    <LayoutTemplate>
        <table border="0" cellpadding="2" cellspacing="0">
        <tr>
        <th>Wholesaler</th>
        <th>Import</th>
        <th>Period</th>
        <th>Upload Date</th>
        <th>Upload</th>
        </tr>
            <asp:PlaceHolder ID="itemPlaceholder" runat="server" />
    </table>
    </LayoutTemplate>
    <ItemTemplate>
    <tr class="row1">
        <td><%# DataBinder.Eval(Container.DataItem, "Wholesaler") %></td>
            <td><%# DataBinder.Eval(Container.DataItem, "Import")%></td>
        <td><%# DataBinder.Eval(Container.DataItem, "Period")%></td>
        <td><asp:DropDownList runat="server" ID="DaysDropDownList"></asp:DropDownList></td>
       <td><asp:FileUpload ID="FileUpload" runat="server" /></td>
    </tr>
    </ItemTemplate>
</asp:ListView>

DropDownList dr = (DropDownList)MyListView.Controls[0].FindControl("DaysDropDownList");
FileUpload fl = (FileUpload)MyListView.Controls[0].FindControl("FileUpload");

Answer 1

You need to iterate over the Items collection of the listview, and then use FindControl on each item. Something like this should put you on the right track:

foreach (var lvItem in MyListView.Items)
{
    if (lvItem.ItemType == ListViewItemType.DataItem)
     {
        DropDownList dr = (DropDownList)lvItem.FindControl("DaysDropDownList");
        FileUpload fl = (FileUpload)lvItem.FindControl("FileUpload");
    }
}

Answer 2

figured...and you got that error, because the listview was not binded yet, so i think the best way would be to do all this on the ItemDataBound event. You would find the dropdownlist like:

protected void FillDropdownlist(object sender, ListViewItemEventArgs e)
    {

     if (e.Item.ItemType == ListViewItemType.DataItem)
        {
            DropDownList dr = (DropDownList)e.Item.FindControl("DaysDropDownList");
            FileUpload fl = (FileUpload)e.Item.FindControl("FileUpload");

            if (dr!= null)
            {
                //code here
            }
        }
}

Answer 3

That's because MyListView.Controls[0] points to an inner control that does not contain those two.

Try debugging and finding precisely which is your container control, and then accessing it directly without a hard coded index. It's accessible via the event parameter of your row binding calls.

Also might I suggest you use the as operator as it doesn't raise an exception:

The as operator is like a cast except that it yields null on conversion failure instead of raising an exception

i.e.

DropDownList dr = e.Item.FindControl("DaysDropDownList") as DropDownList;
FileUpload fl = e.Item.FindControl("FileUpload") as FileUpload;

or after it's bound

//Loop i for the items of your listview
DropDownList dr = MyListView.Items[i].FindControl("DaysDropDownList") as DropDownList;
FileUpload fl = MyListView.Items[i].FindControl("FileUpload") as FileUpload;