Hello Christian,
You need to add a RadMultiColumnComboBox to a RadMenuHostItem and add that to the RadRibbonBar. The example below (just a ribbonbar on a form) shows an sample of this.
Imports Telerik.WinControls.UI
Imports Telerik.WinControls
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles MyBase.Load
Dim people As New List(Of Person)
people.Add(New Person(1, "Richard"))
people.Add(New Person(2, "Peter"))
people.Add(New Person(3, "Fred"))
Dim multiColomnCombo As New Telerik.WinControls.UI.RadMultiColumnComboBox()
multiColomnCombo.DataSource = people
multiColomnCombo.ValueMember = "Id"
multiColomnCombo.DisplayMember = "Name"
Dim hostedControl As New RadMenuHostItem(multiColomnCombo)
Me.RadRibbonBarGroup2.Items.Add(hostedControl)
End Sub
End Class
Public Class Person
Private m_Id As Integer
Private m_Name As String
Public Sub New(id as Integer, name as String)
m_Id = id
m_Name = name
End Sub
Public ReadOnly Property Name() As String
Get
Return m_Name
End Get
End Property
Public ReadOnly Property Id() As Integer
Get
Return m_Id
End Get
End Property
End Class
Hope that helps
Richard