Adding a default option to RadComboBox

[Neil]

I am using a RadComboBox with EnableLoadOnDemand="true", and OnItemsRequested="brand_ItemsRequested" - I want to add a default item that appears at the top of the list, so I have added comboBrand.Items.Insert(0, new RadComboBoxItem("All Brands", "0")); 

protected void brand_ItemsRequested(object sender, RadComboBoxItemsRequestedEventArgs e)
        {
            DataTable data = GetData(e.Text);

            int itemOffset = e.NumberOfItems;
            int endOffset = Math.Min(itemOffset + ItemsPerRequest, data.Rows.Count);
            e.EndOfItems = endOffset == data.Rows.Count;

            for (int i = itemOffset; i < endOffset; i++)
            {
                comboBrand.Items.Add(new RadComboBoxItem(data.Rows[i]["Name"].ToString(), data.Rows[i]["Name"].ToString()));
            }

            comboBrand.Items.Insert(0, new RadComboBoxItem("All Brands", "0"));
            e.Message = GetStatusMessage(endOffset, data.Rows.Count);
        }

<telerik:RadComboBox ID="comboBrand" AppendDataBoundItems="true"  LoadingMessage="Retrieving Brands..." AutoPostBack="true" runat="server" Width="250px" Height="150px"
            EnableLoadOnDemand="true" ShowMoreResultsBox="true" ShowWhileLoading="false"
            EnableVirtualScrolling="true" OnSelectedIndexChanged="comboBrand_SelectedIndexChanged"
            OnItemsRequested="brand_ItemsRequested">
        </telerik:RadComboBox>

The trouble is, each time more results load and appends to the list, "All Brands" is also appended to the results that are returned, so it appears every 12th row. How can I insert just a single default value at the top of the list?

EDIT:

I tried wrapping some logic around the the  comboBrand.items.insert to check for the item before inserting the default item, but multiple items are still being added:

if (!comboBrand.Items.Contains(new RadComboBoxItem("All Brands", "All Brands")))
            {
                comboBrand.Items.Insert(0, new RadComboBoxItem("All Brands", "All Brands"));
            }

[Simon]

Hello Neil,

Your approach does not work because Items already loaded in the RadComboBox are not available on subsequent Items request, i.e. they exist only on the client-side.

Alternatively, you can verify e.NumberOfItems (which holds the number of Items currently loaded on the client-side) and add the default Item only the value is 0.

 

Best wishes,
Simon
the Telerik team

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