TreeList.ShowFilterPopupListBox Event

Enables you to customize a particular Column’s Filter DropDown.

Namespace: DevExpress.XtraTreeList

Assembly: DevExpress.XtraTreeList.v18.2.dll

Declaration

C#

[DXCategory("Behavior")]
public event FilterPopupListBoxEventHandler ShowFilterPopupListBox

VB.NET

<DXCategory("Behavior")>
Public Event ShowFilterPopupListBox As FilterPopupListBoxEventHandler

Event Data

The ShowFilterPopupListBox event's data class is DevExpress.XtraTreeList.FilterPopupListBoxEventArgs.

Remarks

The ShowFilterPopupListBox event fires before the Column’s Filter DropDown is displayed. Write a handler for this event to manage the items within the list. Existing items can be deleted and new ones added with custom captions and corresponding filter values.

Example

The following example shows how to remove default “(Blanks)” and “(Non blanks) items from the Name Column’s Filter DropDown.

 

Note

A complete sample project is available at https://github.com/DevExpress-Examples/an-example-of-using-the-showfilterpopuplistbox-event-e3531

Form1.cs

using System;
using System.Windows.Forms;
using DevExpress.XtraTreeList;

namespace ShowFilterPopupListBox_example
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void treeList1_ShowFilterPopupListBox(object sender, FilterPopupListBoxEventArgs e)
        {
            if (e.Column.FieldName == "Name")
            {
                //Removes "(Blanks)"
                e.ComboBox.Items.RemoveAt(0);
                //Removes "(Non blanks)"
                e.ComboBox.Items.RemoveAt(0);
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.table1TableAdapter.Fill(this.treelistdbDataSet.Table1);

        }
    }
}

Form1.vb

Imports Microsoft.VisualBasic
Imports System
Imports System.Windows.Forms
Imports DevExpress.XtraTreeList

Namespace ShowFilterPopupListBox_example
    Partial Public Class Form1
        Inherits Form
        Public Sub New()
            InitializeComponent()
        End Sub

        Private Sub treeList1_ShowFilterPopupListBox(ByVal sender As Object, ByVal e As FilterPopupListBoxEventArgs) Handles treeList1.ShowFilterPopupListBox
            If e.Column.FieldName = "Name" Then
                'Removes "(Blanks)"
                e.ComboBox.Items.RemoveAt(0)
                'Removes "(Non blanks)"
                e.ComboBox.Items.RemoveAt(0)
            End If
        End Sub

        Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
            Me.table1TableAdapter.Fill(Me.treelistdbDataSet.Table1)

        End Sub
    End Class
End Namespace