RadListBox and RadComboBox controls have been replaced by two brand new controls as of Q2 2010: RadListControl and RadDropDownList. The new controls provide the extensibility options that were currently lacking in the old controls, and offer much better performance, due to the use of virtualization and a new generic data engine, developed for RadGridView.
RadDropDownList replaces RadComboBox and will soon offer extended and new auto complete options.
RadListControl replaces RadListBox and offers full virtualization support. It performs far better than both RadListBox and the standard ListBox control when bound to more than 1000 items. Read more in this blog post: Blazing-fast list control. Meet RadListControl for WinForms.
Both controls are easier to use and customize, and will provide better grounds for developing new features faster.
The old controls will be supported for at least one year after the release of Q2 2010. Users will nevertheless be encouraged to use the new controls since they address the fundamental shortcomings of the previous controls.
Upgrading from the old to the new controls should be easy and painless, unless you have extended the previous controls with custom functionality. If this is the case, please contact Telerik support and we will help you move to the new versions. We will also provide an automatic upgrade tool with Q2 2010 SP1.
Videos and instructions on how to upgrade from the old versions to the new ones will be posted shortly.
To get technical support, either contact Telerik support or post in the DropDownList and ListControl Forum.






private void SetupSpecialControls() {    RadButtonElement buttonElement = new RadButtonElement("...");    buttonElement.Click += buttonElement_Click;    RadTextBoxItem textBoxItem = Text_Update_BI_BatchNo.TextBoxElement.TextBoxItem;    textBoxItem.Alignment = ContentAlignment.MiddleLeft;    Text_Update_BI_BatchNo.TextBoxElement.Children.Remove(textBoxItem);    DockLayoutPanel.SetDock(textBoxItem, Telerik.WinControls.Layouts.Dock.Left);    DockLayoutPanel.SetDock(buttonElement, Telerik.WinControls.Layouts.Dock.Right);    DockLayoutPanel dockLayoutPanel = new DockLayoutPanel();    dockLayoutPanel.Children.Add(buttonElement);    dockLayoutPanel.Children.Add(textBoxItem);    Text_Update_BI_BatchNo.TextBoxElement.Children.Add(dockLayoutPanel);  }


Public Class Form1     Private Sub Form1_Load() Handles Me.Load         Dim x As New ItemModel         RadDropDownList1.DataSource = x.ListItems         RadDropDownList1.ValueMember = "ItemNumber"        RadDropDownList1.AutoCompleteMode = AutoCompleteMode.SuggestAppend         RadDropDownList1.AutoCompleteValueMember = "ItemNumber"    End Sub      Private Sub radDropDownList1_ItemDataBound(ByVal sender As Object, ByVal args As Telerik.WinControls.UI.ListItemDataBoundEventArgs) Handles RadDropDownList1.ItemDataBound         Dim view As DataRowView = CType(args.NewItem.DataBoundItem, DataRowView)         args.NewItem.Text = "<html><b>" & view("ItemNumber") & " • " & view("ItemName") & "</b><br/>" & view("Description") & "</html>"        args.NewItem.Height = 40     End Sub      Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click         MessageBox.Show(RadDropDownList1.SelectedValue)     End SubEnd Class