ToolTipController.GetActiveObjectInfo Event

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

Namespace: DevExpress.Utils

Assembly: DevExpress.Utils.v19.1.dll

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 handle the GetActiveObjectInfo event. This event is fired when you move the mouse cursor over the control. To provide a tooltip for the control’s element, assign a ToolTipControlInfo object containing tooltip information to the event’s ToolTipControllerGetActiveObjectInfoEventArgs.Info parameter. The event’s ToolTipControllerGetActiveObjectInfoEventArgs.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 ToolTipControllerGetActiveObjectInfoEventArgs.Info parameter must provide tooltip information. The ToolTipControlInfo.Text must specify the tooltip text. 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 a way of implementing custom tooltips for row indicator cells in the XtraGrid control. By default, the grid control does not support tooltips for row indicator cells. To provide tooltips, drop the ToolTipController component onto the grid’s form, assign it to the grid control’s EditorContainer.ToolTipController property and handle the ToolTipController.GetActiveObjectInfo event.

In our example, the tooltips will display the “Row N” text where N is the ordinal number of a row.

C#

using DevExpress.Utils;
using DevExpress.XtraGrid.Views.Grid;
using DevExpress.XtraGrid.Views.Grid.ViewInfo;
//...
private void toolTipController1_GetActiveObjectInfo(object sender, 
ToolTipControllerGetActiveObjectInfoEventArgs e) {
    if(e.SelectedControl != gridControl1) return;

    ToolTipControlInfo info = null;
    //Get the view at the current mouse position
    GridView view = gridControl1.GetViewAt(e.ControlMousePosition) as GridView;
    if(view == null) return;
    //Get the view's element information that resides at the current position
    GridHitInfo hi = view.CalcHitInfo(e.ControlMousePosition);
    //Display a hint for row indicator cells
    if(hi.HitTest == GridHitTest.RowIndicator) {
        //An object that uniquely identifies a row indicator cell
        object o = hi.HitTest.ToString() + hi.RowHandle.ToString();
        string text = "Row "+ hi.RowHandle.ToString();
        info = new ToolTipControlInfo(o, text);         
    }
    //Supply tooltip information if applicable, otherwise preserve default tooltip (if any)
    if (info != null)
        e.Info = info;
}

VB.NET

Imports DevExpress.XtraGrid.Views.Grid
Imports DevExpress.XtraGrid.Views.Grid.ViewInfo

Private Sub ToolTipController1_GetActiveObjectInfo(ByVal sender As Object, _ 
ByVal e As DevExpress.Utils.ToolTipControllerGetActiveObjectInfoEventArgs) _
Handles ToolTipController1.GetActiveObjectInfo
    If Not e.SelectedControl Is gridControl1 Then Return

    Dim info As ToolTipControlInfo = Nothing
    'Get the view at the current mouse position
    Dim view As GridView = gridControl1.GetViewAt(e.ControlMousePosition)
    If view Is Nothing Then Return
    'Get the view's element information that resides at the current position
    Dim hi As GridHitInfo = view.CalcHitInfo(e.ControlMousePosition)
    'Display a hint for row indicator cells
    If hi.HitTest = GridHitTest.RowIndicator Then
        'An object that uniquely identifies a row indicator cell
        Dim o As Object = hi.HitTest.ToString() + hi.RowHandle.ToString()
        Dim text As String = "Row " + hi.RowHandle.ToString()
        info = New ToolTipControlInfo(o, text)
    End If
    'Supply tooltip information if applicable, otherwise preserve default tooltip (if any)
    If Not info Is Nothing Then e.Info = info
End Sub

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#

custom-editor-how-to-create-a-fileedit-e4097/CS/CustomEditor/FileEdit.cs#L24

    ToolTipController.DefaultController.GetActiveObjectInfo += new ToolTipControllerGetActiveObjectInfoEventHandler(tooltip_GetActiveObjectInfo);
}

how-to-provide-supertooltip-with-design-time-support-for-any-control-e2311/CS/E2311/Helper/MyNavBarSuperTipHelper.cs#L20

    _Items = new MyNavBarSuperToolTipItemsCollection();
    ToolTipController.DefaultController.GetActiveObjectInfo += DefaultController_GetActiveObjectInfo;
}

how-to-use-a-custom-usercontrol-as-a-tooltip-e4533/CS/ToolTipControllerExample/Form1.cs#L20

    //myToolTipController1.ToolTipControl = new ToolTipControl();
    myToolTipController1.GetActiveObjectInfo += new ToolTipControllerGetActiveObjectInfoEventHandler(myToolTipController1_GetActiveObjectInfo);
}

how-to-display-a-hint-for-an-active-editor-within-the-xtragrid-e749/CS/WindowsApplication1/Form1.cs#L30

{
    gridView.ActiveEditor.ToolTipController.GetActiveObjectInfo += new DevExpress.Utils.ToolTipControllerGetActiveObjectInfoEventHandler(ToolTipController_GetActiveObjectInfo);
}

how-to-show-multiple-group-summary-items-in-the-same-group-footer-cell-in-bandedgridview-e4900/CS/MyGridCtrl/ToolTipHelper.cs#L18

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

VB.NET

custom-editor-how-to-create-a-fileedit-e4097/VB/CustomEditor/FileEdit.vb#L26

    AddHandler ToolTipController.DefaultController.GetActiveObjectInfo, AddressOf tooltip_GetActiveObjectInfo
End Sub

how-to-provide-supertooltip-with-design-time-support-for-any-control-e2311/VB/E2311/Helper/MyNavBarSuperTipHelper.vb#L19

    _Items = New MyNavBarSuperToolTipItemsCollection()
    AddHandler ToolTipController.DefaultController.GetActiveObjectInfo, AddressOf DefaultController_GetActiveObjectInfo
End Sub

how-to-use-a-custom-usercontrol-as-a-tooltip-e4533/VB/ToolTipControllerExample/Form1.vb#L22

    'myToolTipController1.ToolTipControl = new ToolTipControl();
    AddHandler myToolTipController1.GetActiveObjectInfo, AddressOf myToolTipController1_GetActiveObjectInfo
End Sub

how-to-display-a-hint-for-an-active-editor-within-the-xtragrid-e749/VB/WindowsApplication1/Form1.vb#L26

If gridView.ActiveEditor.ToolTipController IsNot Nothing Then
    AddHandler gridView.ActiveEditor.ToolTipController.GetActiveObjectInfo, AddressOf ToolTipController_GetActiveObjectInfo
End If

how-to-show-multiple-group-summary-items-in-the-same-group-footer-cell-in-bandedgridview-e4900/VB/MyGridCtrl/ToolTipHelper.vb#L19

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