Filter Editor

Users can invoke the Filter Editor in the following ways:

• Right-click the column's header and select Filter Editor...:

  

• Click the Edit Filter button ( ) in the Filter Panel:

  

To invoke the Filter Editor in code, call the DataViewBase.ShowFilterEditor method or the DataViewCommandsBase.ShowFilterEditor command:

<Button Content="Show Filter Editor" Command="{Binding Path=Commands.ShowFilterEditor, ElementName=view}" /> 

<!-- ... --> 

<dxg:GridControl> 
    <dxg:GridControl.View> 
        <dxg:TableView x:Name="view" /> 
    </dxg:GridControl.View> 
</dxg:GridControl> 

The Filter Editor displays filter criteria as a tree structure where nodes are filter conditions. The Filter Editor groups filter conditions by logical operators if the filter criteria consist of several filter conditions.

Use the DataViewBase.FilterEditorTemplate property to specify a custom data template. In the template, define the FilterEditorControl and handle its events.

Customize the Field List

The Filter Editor shows a list of the GridControl's fields. If the GridControl has Bands, the Filter Editor shows fields in a hierarchical structure:

Use the FilterEditorControl.QueryFields event to customize the field list. The following code sample shows how to add the ShipCountry, ShipCity, ShipAddress fields to the Ship category:

<dxg:TableView x:Name="view"> 
    <dxg:TableView.FilterEditorTemplate> 
        <DataTemplate> 
            <dxfui:FilterEditorControl QueryFields="OnQueryFields" /> 
        </DataTemplate> 
    </dxg:TableView.FilterEditorTemplate> 
</dxg:TableView> 

void OnQueryFields(object sender, QueryFieldsEventArgs e) {
    var shipCountry = e.Fields["ShipCountry"];
    var shipCity = e.Fields["ShipCity"];
    var shipAddress = e.Fields["ShipAddress"];

    shipCountry.Caption = "Country";
    shipCity.Caption = "City";
    shipAddress.Caption = "Address";

    e.Fields.Remove(shipCountry);
    e.Fields.Remove(shipCity);
    e.Fields.Remove(shipAddress);

    var shipGroup = new FieldItem { Caption = "Ship" };
    shipGroup.Children.Add(shipCountry);
    shipGroup.Children.Add(shipCity);
    shipGroup.Children.Add(shipAddress);
    e.Fields.Add(shipGroup);
} 

Private Sub OnQueryFields(ByVal sender As Object, ByVal e As QueryFieldsEventArgs)
    Dim shipCountry = e.Fields("ShipCountry")
    Dim shipCity = e.Fields("ShipCity")
    Dim shipAddress = e.Fields("ShipAddress")

    shipCountry.Caption = "Country" 
    shipCity.Caption = "City" 
    shipAddress.Caption = "Address" 

    e.Fields.Remove(shipCountry)
    e.Fields.Remove(shipCity)
    e.Fields.Remove(shipAddress)

    Dim shipGroup = New FieldItem With {
        .Caption = "Ship" 
    }
    shipGroup.Children.Add(shipCountry)
    shipGroup.Children.Add(shipCity)
    shipGroup.Children.Add(shipAddress)
    e.Fields.Add(shipGroup)
End Sub 

Customize the Operator List

Standard Operators

The Filter Editor shows a list of operators the selected field accepts. Use the FilterEditorControl.QueryOperators event to customize the operator list.

The code sample below removes all operators except Equal and Not Equal:

<dxg:TableView x:Name="view"> 
    <dxg:TableView.FilterEditorTemplate> 
        <DataTemplate> 
            <dxfui:FilterEditorControl QueryOperators="OnQueryOperators" /> 
        </DataTemplate> 
    </dxg:TableView.FilterEditorTemplate> 
</dxg:TableView> 

void OnQueryOperators(object sender, FilterEditorQueryOperatorsEventArgs e) {
    if(e.FieldName == "OrderDate") {
        e.Operators.Clear();
        e.Operators.Add(new FilterEditorOperatorItem(FilterEditorOperatorType.Equal));
        e.Operators.Add(new FilterEditorOperatorItem(FilterEditorOperatorType.NotEqual));
    }
} 

Private Sub OnQueryOperators(ByVal sender As Object, ByVal e As FilterEditorQueryOperatorsEventArgs)
    If e.FieldName = "OrderDate" Then 
        e.Operators.Clear()
        e.Operators.Add(New FilterEditorOperatorItem(FilterEditorOperatorType.Equal))
        e.Operators.Add(New FilterEditorOperatorItem(FilterEditorOperatorType.NotEqual))
    End If 
End Sub 

Custom Operators

You can use the FilterEditorControl.QueryOperators event to add custom operators. The code sample below adds the Last Years operator:

1. Create a custom function. Do one of the following:

   • Use the CustomFunctionFactory.Create method.

     The CustomFunctionFactory is an extension of the DevExpress.Xpf.Grid.v19.1.Extensions.dll library. Refer to c:\Program Files (x86)\DevExpress 19.1\Components\Sources\DevExpress.Xpf.Grid\DevExpress.Xpf.Grid.Extensions\ for information on how extension methods work.

     The CustomFunctionFactory.Create method allows you to create a custom function with a maximum of 4 operands.

   • Implement the ICustomFunctionOperator interface. Refer to the Implementing Custom Functions topic for more information.

   C#	const string CustomFunctionName = "LastYears"; var currentYear = DateTime.Now.Year; ICustomFunctionOperatorBrowsable customFunction = CustomFunctionFactory.Create(CustomFunctionName, (DateTime date, int threshold) => { return currentYear >= date.Year && currentYear - date.Year <= threshold; } );
   VB	Const CustomFunctionName As String = "LastYears"  Private currentYear = DateTime.Now.Year Dim customFunction As ICustomFunctionOperatorBrowsable = CustomFunctionFactory.Create(CustomFunctionName, Function(ByVal date As DateTime, ByVal threshold As Integer) currentYear >= date.Year AndAlso currentYear - date.Year <= threshold)

2. Call the CriteriaOperator.RegisterCustomFunction method to register the custom function.

   C#	CriteriaOperator.RegisterCustomFunction(customFunction);
   VB	CriteriaOperator.RegisterCustomFunction(customFunction)

3. Create the FilterEditorOperatorItem and add it to the FilterEditorQueryOperatorsEventArgs.Operators collection. Specify the operator item's edit settings (see BaseEditSettings) to define its operands:

   C#

   void OnQueryOperators(object sender, FilterEditorQueryOperatorsEventArgs e) { if(e.FieldName == "OrderDate") { // ...  var customFunctionEditSettings = new BaseEditSettings[] { new TextEditSettings { MaskType = MaskType.Numeric, Mask = "D", MaskUseAsDisplayFormat = true } }; e.Operators.Add(new FilterEditorOperatorItem(CustomFunctionName, customFunctionEditSettings) { Caption = "Last Years" }); } }

   VB

   Private Sub OnQueryOperators(ByVal sender As Object, ByVal e As FilterEditorQueryOperatorsEventArgs) If e.FieldName = "OrderDate" Then  ' ...  Dim customFunctionEditSettings = New BaseEditSettings() {New TextEditSettings With { .MaskType = MaskType.Numeric, .Mask = "D", .MaskUseAsDisplayFormat = True  }} e.Operators.Add(New FilterEditorOperatorItem(CustomFunctionName, customFunctionEditSettings) With { .Caption = "Last Years"  }) End If  End Sub

Predefined Filters

You can specify Predefined Filters with the ColumnBase.PredefinedFilters property. The Filter Editor displays these filters in the Predefined filters submenu:

<dxg:GridColumn FieldName="UnitPrice"> 
    <dxg:GridColumn.PredefinedFilters> 
        <dxfui:PredefinedFilterCollection> 
            <dxfui:PredefinedFilter Name="Less than 10" Filter="?p &lt; 10" /> 
            <dxfui:PredefinedFilter Name="Between 10 and 50" Filter="?p &gt; 10 and ?p &lt; 50" /> 
            <dxfui:PredefinedFilter Name="Between 50 and 100" Filter="?p &gt; 50 and ?p &lt; 100" /> 
            <dxfui:PredefinedFilter Name="Greater than 100" Filter="?p &gt; 100" /> 
        </dxfui:PredefinedFilterCollection> 
    </dxg:GridColumn.PredefinedFilters> 
</dxg:GridColumn> 

Customize Operand Template

The Filter Editor automatically creates operand editors based on the field and operator type. You can customize operand editors.

The following code sample specifies the TrackBarEdit as an operand for the Between and NotBetween operators:

1. Create a template for the operands. The following models depend on the operator type. Use their properties to bind to operand values in the template:

   • ConstantFilterModel (see ConstantFilterModel) (e.g., Is null, Is Yesterday)
   • BinaryFilterModel (see BinaryFilterModel<T>) (e.g., Equals, Is greater than)
   • TernaryFilterModel (see TernaryFilterModel) (e.g., Is between, Is between dates)
   • VariadicFilterModel (see VariadicFilterModel) (e.g., Is any of, Is none of)

   Xaml

   <UserControl.Resources>  <DataTemplate x:Key="ternaryTemplate">  <dxe:TrackBarEdit Minimum="0" Maximum="300" MinWidth="120"  TickPlacement="None" dxfui:FilterEditorNavigation.Index="0">  <dxe:TrackBarEdit.EditValue>  <MultiBinding Converter="{local:TrackBarEditRangeConverter}">  <Binding Path="Left"/>  <Binding Path="Right"/>  </MultiBinding>  </dxe:TrackBarEdit.EditValue>  <dxe:TrackBarEdit.StyleSettings>  <dxe:TrackBarRangeStyleSettings />  </dxe:TrackBarEdit.StyleSettings>  </dxe:TrackBarEdit>  </DataTemplate>  </UserControl.Resources>

   C#

   public class TrackBarEditRangeConverter : BaseMultiValueConverter { public override object Convert(object[] values, Type targetType, object parameter, CultureInfo culture) { if(values.Length != 2) return new TrackBarEditRange(); return new TrackBarEditRange(GetApproptiateValue(values[0]), GetApproptiateValue(values[1])); } short GetApproptiateValue(object value) { if(value is int) return System.Convert.ToInt16(value); return value is short ? (short)value : (short)0; } public override object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture) { var trackBarEditRange = value as TrackBarEditRange; if(trackBarEditRange == null) return new object[] { (short)0, (short)0 }; return new object[] { (short)trackBarEditRange.SelectionStart, (short)trackBarEditRange.SelectionEnd }; } }

   VB

   Public Class TrackBarEditRangeConverter Inherits BaseMultiValueConverter Public Overrides Function Convert(ByVal values As Object(), ByVal targetType As Type, ByVal parameter As Object, ByVal culture As CultureInfo) As Object  If values.Length <> 2 Then Return New TrackBarEditRange() Return New TrackBarEditRange(GetApproptiateValue(values(0)), GetApproptiateValue(values(1))) End Function  Private Function GetApproptiateValue(ByVal value As Object) As Short  If TypeOf value Is Integer Then Return System.Convert.ToInt16(value) Return If(TypeOf value Is Short, CShort(value), CShort(0)) End Function  Public Overrides Function ConvertBack(ByVal value As Object, ByVal targetTypes As Type(), ByVal parameter As Object, ByVal culture As CultureInfo) As Object() Dim trackBarEditRange = TryCast(value, TrackBarEditRange) If trackBarEditRange Is Nothing Then Return New Object() {CShort(0), CShort(0)} Return New Object() {CShort(trackBarEditRange.SelectionStart), CShort(trackBarEditRange.SelectionEnd)} End Function  End Class

2. Handle the FilterEditorControl.QueryOperators event, get the operator, and assign the created template to the OperatorItemBase.OperandTemplate property.

   Xaml	<dxg:TableView x:Name="view">  <dxg:TableView.FilterEditorTemplate>  <DataTemplate>  <dxfui:FilterEditorControl QueryOperators="OnQueryOperators" />  </DataTemplate>  </dxg:TableView.FilterEditorTemplate>  </dxg:TableView>

   C#	void OnQueryOperators(object sender, FilterEditorQueryOperatorsEventArgs e) { if(e.FieldName == "Quantity") { var template = (DataTemplate)FindResource("ternaryTemplate"); e.Operators[FilterEditorOperatorType.Between].OperandTemplate = template; e.Operators[FilterEditorOperatorType.NotBetween].OperandTemplate = template; } }
   VB	Private Sub OnQueryOperators(ByVal sender As Object, ByVal e As FilterEditorQueryOperatorsEventArgs) If e.FieldName = "Quantity" Then  Dim template = CType(FindResource("ternaryTemplate"), DataTemplate) e.Operators(FilterEditorOperatorType.Between).OperandTemplate = template e.Operators(FilterEditorOperatorType.NotBetween).OperandTemplate = template End If  End Sub

Prohibit Operations

Prohibit Group Types

Use the FilterEditorControl.QueryGroupTypes event to prohibit group types. The following code sample prohibits users from specifying the Or and NotOr logical operators:

<dxg:TableView x:Name="view"> 
    <dxg:TableView.FilterEditorTemplate> 
        <DataTemplate> 
            <dxfui:FilterEditorControl QueryGroupTypes="OnQueryGroupTypes" /> 
        </DataTemplate> 
    </dxg:TableView.FilterEditorTemplate> 
</dxg:TableView> 

void OnQueryGroupTypes(object sender, QueryGroupTypesEventArgs e) {
    e.AllowNotAnd = false;
    e.AllowNotOr = false;
} 

Private Sub OnQueryGroupTypes(ByVal sender As Object, ByVal e As QueryGroupTypesEventArgs)
    e.AllowNotAnd = False 
    e.AllowNotOr = False 
End Sub 

Prohibit Group Operations

Use the FilterEditorControl.QueryGroupOperations event to prohibit group operations. The following code sample prohibits users from adding custom Expressions:

<dxg:TableView x:Name="view"> 
    <dxg:TableView.FilterEditorTemplate> 
        <DataTemplate> 
            <dxfui:FilterEditorControl QueryGroupOperations="OnQueryGroupOperations" /> 
        </DataTemplate> 
    </dxg:TableView.FilterEditorTemplate> 
</dxg:TableView> 

void OnQueryGroupOperations(object sender, QueryGroupOperationsEventArgs e) {
    e.AllowAddCustomExpression = false;
} 

Private Sub OnQueryGroupOperations(ByVal sender As Object, ByVal e As QueryGroupOperationsEventArgs)
    e.AllowAddCustomExpression = False 
End Sub 

Prohibit Removing Conditions

Use the FilterEditorControl.QueryConditionOperations event to prohibit users from removing conditions:

<dxg:TableView x:Name="view"> 
    <dxg:TableView.FilterEditorTemplate> 
        <DataTemplate> 
            <dxfui:FilterEditorControl QueryConditionOperations="OnQueryConditionOperations" /> 
        </DataTemplate> 
    </dxg:TableView.FilterEditorTemplate> 
</dxg:TableView> 

void OnQueryConditionOperations(object sender, QueryConditionOperationsEventArgs e) {
    e.AllowRemoveCondition = false;
} 

Private Sub OnQueryConditionOperations(ByVal sender As Object, ByVal e As QueryConditionOperationsEventArgs)
    e.AllowRemoveCondition = False 
End Sub 

You can use a standalone FilterEditorControl to edit filters outside of the GridControl.

Specify the FilterEditorControl.Context property to associate the FilterEditorControl with the GridControl's filtering context:

• The FilterEditorControl retrieves values, filter criteria, format settings and other details from the GridControl's context.
• The FilterEditorControl applies filter criteria to the GridControl's context.

The filter criteria specified in the FilterEditorControl are not automatically applied to the GridControl. To apply the current filter criteria, call the FilterEditorControl.ApplyFilter method or the FilterEditorCommands.ApplyFilter command.

<dxg:GridControl x:Name="filterGrid" ... /> 

<!-- ... --> 

<dxfui:FilterEditorControl x:Name="filterEditor" Context="{Binding Path=FilteringContext, ElementName=filterGrid}"/> 
<Button Content="Apply Filter" Command="{Binding Commands.ApplyFilter, ElementName=filterEditor}" />