title: ComboBox ItemList SelectedValue
body: <p>VB.NET (2010)</p>
  
  <p>I'm trying to create a ComboBox with a Value and Display items. Here are the relevant bits of code. I originally tried to use a datatable with exactly the same result:</p>
  
  <pre><code>Private Sub Form1_Load(sender As Object, e As System.EventArgs) Handles Me.Load
      Try
          cmbFromGroup.Items.Clear()
          ItemList.Clear()
          Item = New SelectionItem(KeyValue, DisplayValue)
          'Link combobox and Item
          ItemList.Add(Item)
          cmbFromGroup.DataSource = ItemList
          cmbFromGroup.DisplayMember = "Display"
          cmbFromGroup.ValueMember = "Key"
      Catch ex As Exception
          Stop
      End Try
  End Sub
  
  Private Sub cmbFromGroup_SelectedIndexChanged(sender As System.Object, e As System.EventArgs) Handles cmbFromGroup.SelectedIndexChanged
      Try
          cmbFromMP3.Items.Clear()
          Dim x As String = cmbFromGroup.SelectedValue
          ' &lt;snip&gt;
          cmbFromMP3.SelectedIndex = 0
      Catch ex As Exception
          Stop
      End Try
  End Sub
  
  Public Interface ISelectionItem
      Property Key As String
      Property Display As String
  End Interface
  
  Public Class SelectionItem
      Implements ISelectionItem
  
      Public Sub New(ByVal vKey As String, ByVal vDisplay As String)
          _Key = vKey
          _Display = vDisplay
      End Sub
  
      Public Property Key As String Implements ISelectionItem.Key
      Public Property Display As String Implements ISelectionItem.Display
  
  End Class
  </code></pre>
  
  <p>The problem I'm having is that cmbFromGroup.SelectedValue doesn't contain the value of the selected item.</p>
  
  <p>What I'm getting is (from Watch)
  cmbFromGroup.SelectedValue  {Player.SelectionItem}  Object</p>
  
  <p>The only options I get from cmbFromGroup.SelectedValue are Equals,GetHashCode, GetType, ReferenceEquals and ToString, none of which give me the ValueMember as I'm expecting.</p>
  
  <p>How do I get the ValueMember from the selected item?</p>