Public Class Form1
    Public Sub New()
        InitializeComponent()
        For Each c As Control In Me.Controls
            If c.GetType Is GetType(ComboBox) Then
                AddHandler CType(c, ComboBox).Click, AddressOf ComboBoxAll_Click
            End If
        Next
    End Sub
 
    Private Sub ComboBoxAll_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs)
        Debug.WriteLine("ComboBox clicked: " & CType(sender, ComboBox).Name)
    End Sub
End Class