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Xceed Toolkit Plus for WPF v5.0 Documentation
Welcome to Xceed Toolkit Plus for WPF v5.0 / DataGrid, ListBox, Chart, AvalonDock, and PropertyGrid / Datagrid control / Fundamentals / Manipulating Data / Filtering Data
In This Topic
    Filtering Data
    In This Topic

    Prerequisite Knowledge
    Object Model Overview: DataGridCollectionView Class
    DataGrid Fundamentals: Providing Data

    The items that are displayed in a view can be limited to one or more filtering criteria using either the native CollectionView filtering or automatic filtering meaning that even if an item exists in the underlying data source, it is not necessarily displayed in the view.

    Native CollectionView Filtering

    The data items that are displayed in a grid can be filtered using the Filter property of the DataGridCollectionViewBase or the Filter event of the DataGridCollectionViewSourceBase to which it is bound (see Example 1).

    To refilter the data items displayed in a view the Refresh method can be called on the ItemsSource.

    VB.NET Copy Code
    CType( Me.OrdersGrid.ItemsSource, DataGridCollectionView ).Refresh()
    C# Copy Code
    ( ( DataGridCollectionView )this.OrdersGrid.ItemsSource ).Refresh();

    Custom Distinct Values

    By default, the values that are displayed in the auto-filter drop down represent the distinct values as they are extracted from the underlying data source; however, custom distinct values can be provided for one or more item properties rather than the originally extracted distinct values by handling their QueryDistinctValue event and returning the custom value (see Example 3).

    Examples

    All examples in this topic assume that the grid is bound to the Orders table of the Northwind database, unless stated otherwise.

    Example 1: Filtering data items (Filter Event)

    The following example demonstrates how to filter the data items displayed in a grid using the Filter event. Only the data items whose ShipVia property value is "3" will be displayed in the grid.

    XAML
    Copy Code 
    <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}"
                                       Filter="ShipViaFilter"/>
  </Grid.Resources>
  <xcdg:DataGridControl x:Name="OrdersGrid"
                        ItemsSource="{Binding Source={StaticResource cvs_orders}}"/>
</Grid>

    The following code provides the implementation of the ShipViaFilter event. This code should be placed in the "code-behind" of your XAML page.

    VB.NET
    Copy Code 
    Private Sub ShipViaFilter( sender As Object, e As FilterEventArgs )
  Dim value As Object = CType( e.Item, System.Data.DataRow )( "ShipVia" )
  If( Not value Is Nothing ) And ( Not value Is DBNull.Value ) Then
    If CInt( value ) = 3 Then
      e.Accepted = True
    Else
      e.Accepted = False
    End If
  End If
End Sub
    C#
    Copy Code 
    private void ShipViaFilter( object sender, FilterEventArgs e )
{
  object value = ( ( System.Data.DataRow )e.Item )[ "ShipVia" ]; 
  if( ( value != null ) && ( value != DBNull.Value ) )
  {
    if( ( int )value == 3 )
    {
     e.Accepted = true;
    }
    else
    {
     e.Accepted = false;
    }
  }   
}

    The next example demonstrates how to filter data items using the Filter predicate delegate.

    VB.NET
    Copy Code 
    Dim view As New DataGridCollectionView( Orders )
view.Filter = New Predicate(Of Object)( ShipViaFilter )
dataGridControl.ItemsSource = view
Private Function ShipViaFilter( item As Object ) As Boolean
   Dim value As Object = TryCast( item, System.Data.DataRow )( "ShipVia" )
   If( Not value Is Nothing ) And ( value <> DBNull.Value )Then
     If CInt( value ) == 3 Then
       Return True
     End If
   End If
   Return false
End Function
    C#
    Copy Code 
    DataGridCollectionView view = new DataGridCollectionView( Orders );
view.Filter = new Predicate<object>( ShipViaFilter );
dataGridControl.ItemsSource = view;

private bool ShipViaFilter( object item )
{
  object value = ( ( System.Data.DataRow )item )[ "ShipVia" ];
  if( ( value != null ) && ( value != DBNull.Value ) )
  {
    if( ( int )value == 3 )       
      return true;       
  }
  return false;
}

    Example 2: Providing custom distinct values

    The following example demonstrates how to provide custom distinct values that will display the only the month in columns that display DateTime values and that will filter according to a value range for a decimal column.

    XAML
    Copy Code 
    <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}"
                                        AutoFilterMode="And"
                                        DefaultCalculateDistinctValues="False">
        <xcdg:DataGridCollectionViewSource.ItemProperties>
          <xcdg:DataGridItemProperty Name="OrderDate"
                                     QueryDistinctValue="DataGridItemProperty_QueryDistinctValue_Date"
                                     CalculateDistinctValues="True"/>
          <xcdg:DataGridItemProperty Name="RequiredDate"
                                     QueryDistinctValue="DataGridItemProperty_QueryDistinctValue_Date"
                                     CalculateDistinctValues="True" />
          <xcdg:DataGridItemProperty Name="ShippedDate"
                                     QueryDistinctValue="DataGridItemProperty_QueryDistinctValue_Date"
                                     CalculateDistinctValues="True" />
          <xcdg:DataGridItemProperty Name="Freight"
                                     QueryDistinctValue="DataGridItemProperty_QueryDistinctValue_Range"
                                     CalculateDistinctValues="True" />
        </xcdg:DataGridCollectionViewSource.ItemProperties>
     </xcdg:DataGridCollectionViewSource>
  
  </Grid.Resources>
  <xcdg:DataGridControl x:Name="OrdersGrid"
                        ItemsSource="{Binding Source={StaticResource cvs_orders}}"/>
</Grid>
    VB.NET
    Copy Code 
    Private Sub DataGridItemProperty_QueryDistinctValue_Date( ByVal sender As Object, ByVal e As QueryDistinctValueEventArgs )
  If TypeOf e.DataSourceValue Is DateTime Then
    e.DistinctValue = CDate( e.DataSourceValue ).ToString( "MMMM" )
  End If
End Sub
Private Sub DataGridItemProperty_QueryDistinctValue_Range( ByVal sender As Object, ByVal e As QueryDistinctValueEventArgs )
  If TypeOf e.DataSourceValue Is Decimal Then
    Dim value As Decimal = CDec( e.DataSourceValue )
    If value <= 100 Then
      e.DistinctValue = "0 - 100"
    ElseIf( value > 100 And value <= 500 ) Then
      e.DistinctValue = "101 - 500"
    Else
      e.DistinctValue = "500+"
    End If
  End If
End Sub
    C#
    Copy Code 
    private void DataGridItemProperty_QueryDistinctValue_Date( object sender, QueryDistinctValueEventArgs e )
{
 if( e.DataSourceValue is DateTime )
 {
   e.DistinctValue = ( ( DateTime )e.DataSourceValue ).ToString( "MMMM" );
 }
}
private void DataGridItemProperty_QueryDistinctValue_Range( object sender, QueryDistinctValueEventArgs e )
{
 if( e.DataSourceValue is decimal )
 {
   decimal value = ( decimal )e.DataSourceValue;
   if( value <= 100 )
   {
     e.DistinctValue = "0 - 100";
   }
   else if( value > 100 && value <= 500 )
   {
     e.DistinctValue = "101 - 500";
   }
   else
   {
     e.DistinctValue = "500+";
   }
 }
}
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