Display File Name in ToolTip

Updated on Sep 15, 2025

Environment

Product Version	2022.2.511
Product	RadFileDialogs for WPF

Description

How to display a tooltip that contains the name of a file.

Solution

The files in the Extra large icons, Large icons, Medium icons, Small icons, List and Tiles views, are represented by a RadListBoxItem element. To display a tooltip for this element, register two new event handlers for the RadListBoxItem class, via the EventManager.RegisterClassHandler method. These two handlers will be for the MouseEnter and MouseLeave events.

Register new MouseEnter and MouseLeave event handlers

C#

    EventManager.RegisterClassHandler(typeof(RadListBoxItem), RadListBoxItem.MouseEnterEvent, new MouseEventHandler(GetOnMouseEnter), true);
    EventManager.RegisterClassHandler(typeof(RadListBoxItem), RadListBoxItem.MouseLeaveEvent, new MouseEventHandler(GetOnLeaveEnter), true);

VB.NET

    EventManager.RegisterClassHandler(GetType(RadListBoxItem), RadListBoxItem.MouseEnterEvent, New MouseEventHandler(GetOnMouseEnter), True)
    EventManager.RegisterClassHandler(GetType(RadListBoxItem), RadListBoxItem.MouseLeaveEvent, New MouseEventHandler(GetOnLeaveEnter), True)

To reach the name of a file or a directory, cast the Content property of the RadListBoxItem element to either FileInfoWrapper or DirectoryInfoWrapper type. The FileInfoWrapper class contains information for the files and DirectoryInfoWrapper class-for directories. The name for the file or directory can be retrieved, through the Name property of both of these classes.

Cast the Content property and retrieve the file/directory name

C#

    private static void GetOnMouseEnter(object sender, MouseEventArgs e)
    {
        RadListBoxItem item = (RadListBoxItem)sender;

        if (item.Content is FileInfoWrapper)
        {
            FileInfoWrapper infoWrapper = item.Content as FileInfoWrapper;
            string fileName = infoWrapper.Name;
        }
        else if (item.Content is DirectoryInfoWrapper)
        {
            DirectoryInfoWrapper directoryInfoWrapper = item.Content as DirectoryInfoWrapper;
            string directoryName = directoryInfoWrapper.Name;
        }
    }

VB.NET

    Private Shared Sub GetOnMouseEnter(ByVal sender As Object, ByVal e As MouseEventArgs)
        Dim item As RadListBoxItem = CType(sender, RadListBoxItem)

        If TypeOf item.Content Is FileInfoWrapper Then
            Dim infoWrapper As FileInfoWrapper = TryCast(item.Content, FileInfoWrapper)
            Dim fileName As String = infoWrapper.Name
        ElseIf TypeOf item.Content Is DirectoryInfoWrapper Then
            Dim directoryInfoWrapper As DirectoryInfoWrapper = TryCast(item.Content,    DirectoryInfoWrapper)
            Dim directoryName As String = directoryInfoWrapper.Name
        End If
    End Sub

Create a ToolTip class instance and set its Content property to the name of the file/directory. Then, set this instance to the ToolTip property of the RadListBoxItem element.

Create and set ToolTip for RadListBoxItem

C#

    private static void GetOnMouseEnter(object sender, MouseEventArgs e)
    {
        RadListBoxItem item = (RadListBoxItem)sender;

        if (item.Content is FileInfoWrapper)
        {
            FileInfoWrapper infoWrapper = item.Content as FileInfoWrapper;
            string fileName = infoWrapper.Name;

            if (item.ToolTip != null)
            {
                (item.ToolTip as ToolTip).IsOpen = true;
            }
            else
            {
                var tooltip = new ToolTip() { Content = fileName };
                item.ToolTip = tooltip;
                tooltip.IsOpen = true;
            }
        }
        else if (item.Content is DirectoryInfoWrapper)
        {
            DirectoryInfoWrapper directoryInfoWrapper = item.Content as DirectoryInfoWrapper;
            string directoryName = directoryInfoWrapper.Name;

            if (item.ToolTip != null)
            {
                (item.ToolTip as ToolTip).IsOpen = true;
            }
            else
            {
                var tooltip = new ToolTip() { Content = directoryName };
                item.ToolTip = tooltip;
                tooltip.IsOpen = true;
            }
        }
    }

VB.NET

    Private Shared Sub GetOnMouseEnter(ByVal sender As Object, ByVal e As MouseEventArgs)
        Dim item As RadListBoxItem = CType(sender, RadListBoxItem)

        If TypeOf item.Content Is FileInfoWrapper Then
            Dim infoWrapper As FileInfoWrapper = TryCast(item.Content, FileInfoWrapper)
            Dim fileName As String = infoWrapper.Name

            If item.ToolTip IsNot Nothing Then
                (TryCast(item.ToolTip, ToolTip)).IsOpen = True
            Else
                Dim tooltip = New ToolTip() With {
                    .Content = fileName
                }
                item.ToolTip = tooltip
                tooltip.IsOpen = True
            End If
        ElseIf TypeOf item.Content Is DirectoryInfoWrapper Then
            Dim directoryInfoWrapper As DirectoryInfoWrapper = TryCast(item.Content,    DirectoryInfoWrapper)
            Dim directoryName As String = directoryInfoWrapper.Name

            If item.ToolTip IsNot Nothing Then
                (TryCast(item.ToolTip, ToolTip)).IsOpen = True
            Else
                Dim tooltip = New ToolTip() With {
                    .Content = directoryName
                }
                item.ToolTip = tooltip
                tooltip.IsOpen = True
            End If
        End If
    End Sub

To control the delay of the initial display of the tooltip, you can use the RadToolTipService.SetInitialShowDelay method.

Set initial delay

C#

    RadListBoxItem item = (RadListBoxItem)sender;

    var delay = RadToolTipService.GetInitialShowDelay(item);
    if (delay != 0)
    {
        RadToolTipService.SetInitialShowDelay(item, 0);
    }

VB.NET

    Dim item As RadListBoxItem = CType(sender, RadListBoxItem)

    Dim delay = RadToolTipService.GetInitialShowDelay(item)
    If delay <> 0 Then
        RadToolTipService.SetInitialShowDelay(item, 0)
    End If

Inside the registered handler for the MouseLeave event, set the IsOpen property of the ToolTip property to False, to close the tooltip.

Close the tooltip

C#

    private void GetOnLeaveEnter(object sender, MouseEventArgs e)
    {
        RadListBoxItem item = (RadListBoxItem)sender;

        if ((item.ToolTip as ToolTip).IsOpen)
        {
            (item.ToolTip as ToolTip).IsOpen = false;
        }
    }

VB.NET

    Private Sub GetOnLeaveEnter(ByVal sender As Object, ByVal e As MouseEventArgs)
        Dim item As RadListBoxItem = CType(sender, RadListBoxItem)
    
        If (TryCast(item.ToolTip, ToolTip)).IsOpen Then
            (TryCast(item.ToolTip, ToolTip)).IsOpen = False
        End If
    End Sub