ToolTipController.GetActiveObjectInfo Event

Allows you to display custom tooltips for any UI element of a control that implements the DevExpress.Utils.IToolTipControlClient interface.

Namespace: DevExpress.Utils

Assembly: DevExpress.Utils.v24.1.dll

NuGet Packages: DevExpress.Utils, DevExpress.Wpf.Core

Declaration

C#

[DXCategory("Events")]
public event ToolTipControllerGetActiveObjectInfoEventHandler GetActiveObjectInfo

VB.NET

<DXCategory("Events")>
Public Event GetActiveObjectInfo As ToolTipControllerGetActiveObjectInfoEventHandler

Event Data

The GetActiveObjectInfo event's data class is ToolTipControllerGetActiveObjectInfoEventArgs. The following properties provide information specific to this event:

Property	Description
ControlMousePosition	Gets the position of the mouse cursor relative to the control’s upper left corner.
Info	Gets or sets an object which uniquely identifies the visual element at the current position.
SelectedControl	Gets or sets the control for which a tooltip controller’s event is fired. Inherited from ToolTipControllerEventArgsBase.
SelectedObject	Gets or sets the element of the control for which the tooltip should be displayed. Inherited from ToolTipControllerEventArgsBase.

Remarks

DevExpress controls that need to support tooltips for their elements implement the DevExpress.Utils.IToolTipControlClient interface. For instance, the Grid Control implements this interface to display hints for its elements (column and band headers and cells). For other elements, tooltips are not displayed by default.

To enable tooltips for any element of a control that implements the DevExpress.Utils.IToolTipControlClient interface, you need to assign the ToolTipController component to the control’s ToolTipController property and handle the ToolTipController.GetActiveObjectInfo event.

The GetActiveObjectInfo event is fired when you move the mouse pointer over the control. To provide a tooltip for the control’s element, assign a ToolTipControlInfo object containing tooltip information to the event’s e.Info parameter. The event’s e.ControlMousePosition parameter specifies the position of the mouse cursor relative to the control’s upper left corner.

A ToolTipControlInfo object that is assigned to the event’s e.Info parameter must provide tooltip information. The ToolTipControlInfo.Text specifies the text for a regular or super tooltip. The ToolTipControlInfo.FlyoutControl property specifies a flyout tooltip’s content. The ToolTipControlInfo.Object property must uniquely identify the currently processed element. Other properties of the ToolTipControlInfo class can be used to specify the tooltip’s title, icon type and delay.

The value of the ToolTipControlInfo.Object property is used as an identifier. To display different tooltips for a control’s elements, different ToolTipControlInfo objects with different values of the ToolTipControlInfo.Object properties must be used.

You can also handle the ToolTipController.BeforeShow event to customize the tooltip just prior to it being displayed onscreen.

Example

The following example demonstrates how to display custom tooltips for row indicator cells in the WinForms Data Grid control. The Grid control does not display tooltips for row indicator cells by default.

Do the following:

1. Create and initialize a new instance of the ToolTipController class.
2. Assign the ToolTipController to the Grid Control’s GridControl.ToolTipController property.
3. Handle the ToolTipController.GetActiveObjectInfo event.

The image below shows the result:

C#

using System;
using System.Collections.Generic;
using DevExpress.Utils;
using DevExpress.XtraGrid.Views.Grid;
using DevExpress.XtraGrid.Views.Grid.ViewInfo;
using DevExpress.XtraEditors;
using DevExpress.XtraGrid;

namespace DXApplication18 {
    public partial class Form1 : XtraForm {
        ToolTipController tooltipController;
        public Form1() {
            InitializeComponent();
            // Initializes a ToolTip Controller.
            tooltipController = new ToolTipController();
            // Assigns the ToolTip Controller to the GridControl.
            gridControl1.ToolTipController = tooltipController;

            /* Handles the GetAvticeObjectInfo event to display custom tooltips
             * for the grid's row indicator cells.
             */
            tooltipController.GetActiveObjectInfo += tooltipController_GetActiveObjectInfo;

            // Binds the GridControl to data generated at runtime.
            gridControl1.DataSource = Task.GetSampleData();
        }
        void tooltipController_GetActiveObjectInfo(object sender,
ToolTipControllerGetActiveObjectInfoEventArgs e) {
            if (e.SelectedControl != gridControl1) return;

            ToolTipControlInfo info = null;
            // Gets the Data View at the mouse pointer position.
            GridView view = gridControl1.GetViewAt(e.ControlMousePosition) as GridView;
            if (view == null) return;
            // Gets the information about UI element that resides at the mouse pointer position.
            GridHitInfo hi = view.CalcHitInfo(e.ControlMousePosition);
            // Displays a tooltip if the mouse pointer is over a row indicator cell.
            if (hi.HitTest == GridHitTest.RowIndicator) {
                // Gets an object that uniquely identifies the row indicator cell.
                object o = hi.HitTest.ToString() + hi.RowHandle.ToString();
                string text = String.Empty;
                switch (hi.RowHandle) {
                    case GridControl.AutoFilterRowHandle:
                        text = "Auto Filter Row";
                        break;
                    case GridControl.NewItemRowHandle:
                        text = "New Item Row";
                        break;
                    case GridControl.InvalidRowHandle:
                        text = "Invalid Row Handle";
                        break;
                    default:
                        text = String.Format("Row {0}", hi.RowHandle);
                        break;
                }
                info = new ToolTipControlInfo(o, text);
            }

            if(info != null)
                e.Info = info;
        }
    }
    public class Task {
        int fID;
        public Task(int id) {
            fID = id;
            CreateDate = DateTime.Today;
        }
        public int ID {
            get {
                return fID;
            }
        }
        public string Caption { get; set; }
        public DateTime CreateDate { get; set; }
        public static List<Task> GetSampleData() {
            return new List<Task>() {
            new Task(0){Caption = "Research", CreateDate = new DateTime(2022, 10, 15)},
            new Task(1){Caption = "UI Design", CreateDate = new DateTime(2022, 11, 5)},
            new Task(2){Caption = "Environment Setup", CreateDate = new DateTime(2022, 11, 10)},
            new Task(3){Caption = "Sprint 1", CreateDate = new DateTime(2022, 11, 11)},
            new Task(4){Caption = "Sprint 2", CreateDate = new DateTime(2022, 12, 12)},
            new Task(5){Caption = "Sprint 3", CreateDate = new DateTime(2023, 1, 10)},
            new Task(6){Caption = "Testing", CreateDate = new DateTime(2022, 2, 10)}
        };
        }
    }
}

VB.NET

Imports System
Imports System.Collections.Generic
Imports DevExpress.Utils
Imports DevExpress.XtraGrid.Views.Grid
Imports DevExpress.XtraGrid.Views.Grid.ViewInfo
Imports DevExpress.XtraEditors
Imports DevExpress.XtraGrid

Namespace DXApplication18
    Partial Public Class Form1
        Inherits XtraForm

        Private tooltipController As ToolTipController
        Public Sub New()
            InitializeComponent()
            ' Initializes a ToolTip Controller.
            tooltipController = New ToolTipController()
            ' Assigns the ToolTip Controller to the GridControl.
            gridControl1.ToolTipController = tooltipController

            ' Handles the GetAvticeObjectInfo event to display custom tooltips
            ' for the grid's row indicator cells.
            AddHandler tooltipController.GetActiveObjectInfo, AddressOf tooltipController_GetActiveObjectInfo

            ' Binds the GridControl to data generated at runtime.
            gridControl1.DataSource = Task.GetSampleData()
        End Sub
        Private Sub tooltipController_GetActiveObjectInfo(ByVal sender As Object, ByVal e As ToolTipControllerGetActiveObjectInfoEventArgs)
            If e.SelectedControl <> gridControl1 Then
                Return
            End If

            Dim info As ToolTipControlInfo = Nothing
            ' Gets the Data View at the mouse pointer position.
            Dim view As GridView = TryCast(gridControl1.GetViewAt(e.ControlMousePosition), GridView)
            If view Is Nothing Then
                Return
            End If
            ' Gets the information about UI element that resides at the mouse pointer position.
            Dim hi As GridHitInfo = view.CalcHitInfo(e.ControlMousePosition)
            ' Displays a tooltip if the mouse pointer is over a row indicator cell.
            If hi.HitTest = GridHitTest.RowIndicator Then
                ' Gets an object that uniquely identifies the row indicator cell.
                Dim o As Object = hi.HitTest.ToString() & hi.RowHandle.ToString()
                Dim text As String = String.Empty
                Select Case hi.RowHandle
                    Case GridControl.AutoFilterRowHandle
                        text = "Auto Filter Row"
                    Case GridControl.NewItemRowHandle
                        text = "New Item Row"
                    Case GridControl.InvalidRowHandle
                        text = "Invalid Row Handle"
                    Case Else
                        text = String.Format("Row {0}", hi.RowHandle)
                End Select
                info = New ToolTipControlInfo(o, text)
            End If

            If info IsNot Nothing Then
                e.Info = info
            End If
        End Sub
    End Class
    Public Class Task
        Private fID As Integer
        Public Sub New(ByVal id As Integer)
            fID = id
            CreateDate = Date.Today
        End Sub
        Public ReadOnly Property ID() As Integer
            Get
                Return fID
            End Get
        End Property
        Public Property Caption() As String
        Public Property CreateDate() As Date
        Public Shared Function GetSampleData() As List(Of Task)
            Return New List(Of Task)() From {
                New Task(0) With {
                    .Caption = "Research",
                    .CreateDate = New Date(2022, 10, 15)
                },
                New Task(1) With {
                    .Caption = "UI Design",
                    .CreateDate = New Date(2022, 11, 5)
                },
                New Task(2) With {
                    .Caption = "Environment Setup",
                    .CreateDate = New Date(2022, 11, 10)
                },
                New Task(3) With {
                    .Caption = "Sprint 1",
                    .CreateDate = New Date(2022, 11, 11)
                },
                New Task(4) With {
                    .Caption = "Sprint 2",
                    .CreateDate = New Date(2022, 12, 12)
                },
                New Task(5) With {
                    .Caption = "Sprint 3",
                    .CreateDate = New Date(2023, 1, 10)
                },
                New Task(6) With {
                    .Caption = "Testing",
                    .CreateDate = New Date(2022, 2, 10)
                }
            }
        End Function
    End Class
End Namespace

Related GitHub Examples

The following code snippets (auto-collected from DevExpress Examples) contain references to the GetActiveObjectInfo event.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

winforms-listbox-show-item-tooltips/CS/WindowsApplication45/Form1.cs#L17

    listBoxControl1.ToolTipController = toolTipController1;
    toolTipController1.GetActiveObjectInfo+=toolTipController1_GetActiveObjectInfo;
}

winforms-grid-show-multiple-group-summaries-in-group-footer-cell/CS/MultiGroupSummary/ToolTipHelper.cs#L19

    gridCtrl.ToolTipController = toolTipController;
    toolTipController.GetActiveObjectInfo += new ToolTipControllerGetActiveObjectInfoEventHandler(ToolTipController_GetActiveObjectInfo);
}

VB.NET

winforms-listbox-show-item-tooltips/VB/WindowsApplication45/Form1.vb#L15

    listBoxControl1.ToolTipController = toolTipController1
    AddHandler toolTipController1.GetActiveObjectInfo, AddressOf toolTipController1_GetActiveObjectInfo
End Sub

winforms-grid-show-multiple-group-summaries-in-group-footer-cell/VB/MultiGroupSummary/ToolTipHelper.vb#L19

    gridCtrl.ToolTipController = toolTipController
    AddHandler toolTipController.GetActiveObjectInfo, AddressOf ToolTipController_GetActiveObjectInfo
End Sub