How to determine whether a WPF DataGrid is in edit mode?

Possible Duplicate:
Code to check if a cell of a DataGrid is currently edited

Is there a way to determine whether a WPF DataGrid is in edit mode / which row is currently edited?

VB.NET

<Extension>
Public Function GetContainerFromIndex(Of TContainer As DependencyObject) _
    (ByVal itemsControl As ItemsControl, ByVal index As Integer) As TContainer
  Return DirectCast(
    itemsControl.ItemContainerGenerator.ContainerFromIndex(index), TContainer)
End Function

<Extension>
Public Function IsEditing(ByVal dataGrid As DataGrid) As Boolean
  Return dataGrid.GetEditingRow IsNot Nothing
End Function

<Extension>
Public Function GetEditingRow(ByVal dataGrid As DataGrid) As DataGridRow
  Dim sIndex = dataGrid.SelectedIndex
  If sIndex >= 0 Then
    Dim selected = dataGrid.GetContainerFromIndex(Of DataGridRow)(sIndex)
    If selected.IsEditing Then Return selected
  End If

  For i = 0 To dataGrid.Items.Count - 1
    If i = sIndex Then Continue For
    Dim item = dataGrid.GetContainerFromIndex(Of DataGridRow)(i)
    If item.IsEditing Then Return item
  Next

  Return Nothing
End Function

C#:

public static TContainer GetContainerFromIndex<TContainer>
  (this ItemsControl itemsControl, int index)
    where TContainer : DependencyObject
{
  return (TContainer)
    itemsControl.ItemContainerGenerator.ContainerFromIndex(index);
}

public static bool IsEditing(this DataGrid dataGrid)
{
  return dataGrid.GetEditingRow() != null;
}

public static DataGridRow GetEditingRow(this DataGrid dataGrid)
{
  var sIndex = dataGrid.SelectedIndex;
  if (sIndex >= 0)
  {
    var selected = dataGrid.GetContainerFromIndex<DataGridRow>(sIndex);
    if (selected.IsEditing) return selected;
  }

  for (int i = 0; i < dataGrid.Items.Count; i++)
  {
    if (i == sIndex) continue;
    var item = dataGrid.GetContainerFromIndex<DataGridRow>(i);
    if (item.IsEditing) return item;
  }

  return null;
}