Creating a Value-changed Handler

The following example demonstrates how to create a DependencyPropertyDescriptor for the ItemsSource property that will provide a value-changed handler so that we can be notified when the value of the ItemsSource property is changed.

The value of the ItemsSource property is changed to the Employees table when the button located above the grid is clicked.

XAML

  <Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid">
    <Grid.Resources>
      <xcdg:DataGridCollectionViewSource x:Key="cvs_orders"
                                      Source="{Binding Source={x:Static Application.Current},
                                                        Path=Orders}"/>
    </Grid.Resources>
    <DockPanel>
      <Button Content="Change data source"
              DockPanel.Dock="Top"
              Click="ChangeDataSource"/>
        <xcdg:DataGridControl x:Name="OrdersGrid"
                              ItemsSource="{Binding Source={StaticResource cvs_orders}}"
                              DockPanel.Dock="Bottom"/>
    </DockPanel>
  </Grid>

C#

protected override void OnInitialized( EventArgs e )
{
  base.OnInitialized( e );
  DependencyPropertyDescriptor gridItemsSourceDescriptor = DependencyPropertyDescriptor.FromProperty( DataGridControl.ItemsSourceProperty, typeof( DataGridControl ) );
  gridItemsSourceDescriptor.AddValueChanged( this.OrdersGrid, OnDataGridItemsSourceChanged );
}
protected void OnDataGridItemsSourceChanged( object sender, EventArgs args )
{
  // Before assigning the ItemsSource, UpdateLayout must be called to ensure that the
  // DataGridControl's template is created and sized correctly in the page or window.
  this.OrdersGrid.UpdateLayout();
  foreach( Column column in this.OrdersGrid.Columns )
  {
    double width = column.GetFittedWidth();
    if( width > -1 )
    {
      column.Width = width;
    }
  }
}
private void ChangeDataSource( object sender, RoutedEventArgs e )
{
  this.OrdersGrid.Columns.Clear();
  this.OrdersGrid.ItemsSource = null;
    
  this.OrdersGrid.ItemsSource = new DataGridCollectionView( App.Employees.DefaultView );
}

VB.NET

  Protected Overrides Sub OnInitialized( ByVal e As EventArgs )
    MyBase.OnInitialized( e ) 
    Dim gridItemsSourceDescriptor As DependencyPropertyDescriptor = DependencyPropertyDescriptor.FromProperty( DataGridControl.ItemsSourceProperty, GetType( DataGridControl ) )
    gridItemsSourceDescriptor.AddValueChanged( Me.OrdersGrid, _
                                              New EventHandler( AddressOf OnDataGridItemsSourceChanged ) )
  End Sub
  Protected Sub OnDataGridItemsSourceChanged( ByVal sender As Object, _
                                              ByVal args As EventArgs )
    ' Before assigning the ItemsSource, UpdateLayout must be called to ensure that the
    ' DataGridControl's template is created and sized correctly in the page or window.
    Me.OrdersGrid.UpdateLayout()
    Dim column As Column
    For Each column In Me.OrdersGrid.Columns
      Dim width As Double = column.GetFittedWidth()
      If width > -1 Then
        column.Width = width
      End IF
    Next column
  End Sub
  Private Sub ChangeDataSource( ByVal sender As object, ByVal e As RoutedEventArgs )
    Me.OrdersGrid.Columns.Clear()
    Me.OrdersGrid.ItemsSource = Nothing
      
    Me.OrdersGrid.ItemsSource = New DataGridCollectionView( App.Employees.DefaultView )
  End Sub