TreeList.ShowFilterPopupCheckedListBox Event

Allows you to customize checked Column’s Filter DropDown lists before they are displayed.

Namespace: DevExpress.XtraTreeList

Assembly: DevExpress.XtraTreeList.v18.2.dll

Declaration

C#

[DXCategory("Behavior")]
public event FilterPopupCheckedListBoxEventHandler ShowFilterPopupCheckedListBox

VB.NET

<DXCategory("Behavior")>
Public Event ShowFilterPopupCheckedListBox As FilterPopupCheckedListBoxEventHandler

Event Data

The ShowFilterPopupCheckedListBox event's data class is DevExpress.XtraTreeList.FilterPopupCheckedListBoxEventArgs.

Remarks

If the OptionsColumnFilter.FilterPopupMode property is set to CheckedList, the Column’s Filter DropDown is displayed as a checked list. In this mode, you can handle the ShowFilterPopupCheckedListBox event to customize the dropdown (for instance, disable or hide particlar items). This event is raised each time before the filter dropdown is displayed.

Example

The following example shows how to remove the “(Select All)” item from the Department Column’s Filter DropDown.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/an-example-of-using-the-showfilterpopupcheckedlistbox-event-e3542

Form1.cs

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

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

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

        private void treeList1_ShowFilterPopupCheckedListBox(object sender, FilterPopupCheckedListBoxEventArgs e)
        {
            if (e.Column.FieldName != "Department") return;
            // disable "(Select All)" item
            e.CheckedComboBox.SelectAllItemVisible = false;
        }
    }
}

Form1.vb

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

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

        Private Sub treeList1_ShowFilterPopupCheckedListBox(ByVal sender As Object, ByVal e As FilterPopupCheckedListBoxEventArgs) Handles treeList1.ShowFilterPopupCheckedListBox
            If e.Column.FieldName <> "Department" Then
                Return
            End If
            ' disable "(Select All)" item
            e.CheckedComboBox.SelectAllItemVisible = False
        End Sub
    End Class
End Namespace