LookUpEditBase.SubstituteDisplayFilter Event

Allows you to customize the filter applied by LookUpEdit or ComboBoxEdit (for example, to filter data by an additional/another column).

Namespace: DevExpress.Xpf.Editors

Assembly: DevExpress.Xpf.Core.v19.2.dll

Declaration

C#

public event EventHandler<SubstituteDisplayFilterEventArgs> SubstituteDisplayFilter

VB.NET

Public Event SubstituteDisplayFilter As EventHandler(Of SubstituteDisplayFilterEventArgs)

Event Data

The SubstituteDisplayFilter event's data class is DevExpress.Xpf.Editors.Helpers.SubstituteDisplayFilterEventArgs.

Remarks

In the code sample below, an editor filters items by FirstName with the following configuration:

Xaml

<dxg:LookUpEdit DisplayMember="FirstName" .../> 

C#

public class Person {
    public string FirstName { get; set; }
    public string LastName { get; set; }
} 

VB.NET

Public Class Person
    Public Property FirstName As String
    Public Property LastName As String
End Class 

To filter items by both FirstName and LastName, add a corresponding condition in the SubstituteDisplayFilter event handler:

C#

void SubstituteDisplayFilter(object sender, SubstituteDisplayFilterEventArgs e) {
    if (string.IsNullOrEmpty(e.DisplayText))
        return;
    var extraFilter = CriteriaOperator.Parse("StartsWith(LastName,?)", e.DisplayText);
    e.DisplayFilter = new GroupOperator(GroupOperatorType.Or, extraFilter, e.DisplayFilter);
    e.Handled = true;
} 

VB.NET

Private Sub SubstituteDisplayFilter(ByVal sender As Object, ByVal e As SubstituteDisplayFilterEventArgs)
    If String.IsNullOrEmpty(e.DisplayText) Then Return
    Dim extraFilter = CriteriaOperator.Parse("StartsWith(LastName,?)", e.DisplayText)
    e.DisplayFilter = New GroupOperator(GroupOperatorType.[Or], extraFilter, e.DisplayFilter)
    e.Handled = True
End Sub