Windows Forms Listitem Tooltip

Does anyone know if it's possible to give individual list items a tooltip in .NET? It was possible in VB6, so I can't believe the functionality has gone, but I can't find any mention of how to do it.

The reason I'm after this is that my list occasionally contains items which are too big to display, and I'd like to be able to pop-up a tooltip with the full item text.


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you can dynamically change Listbox associated tooltip to display
current selected item, just create a tooltip object ,set its properties to
match listbox selected item.
Something like:

toolTip1.SetToolTip(Me.Listbox1, listbox1.selecteditem.ToString)

LordSauceAuthor Commented:
Ideally I'd like to display a tooltip for the item under the cursor, rather than the selected item.
I am not sure that you can do that. But I might be wrong
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Hi LordSauce:
Based partly on the help example for tooltips

Public Class Form1
    Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

    Public Sub New()

        'This call is required by the Windows Form Designer.

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
            End If
        End If
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    Friend WithEvents ListBox1 As System.Windows.Forms.ListBox
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.ListBox1 = New System.Windows.Forms.ListBox
        Me.ListBox1.Items.AddRange(New Object() {"Hello, how are you today!", "I am well thanks!"})
        Me.ListBox1.Location = New System.Drawing.Point(56, 64)
        Me.ListBox1.Name = "ListBox1"
        Me.ListBox1.Size = New System.Drawing.Size(96, 30)
        Me.ListBox1.TabIndex = 0
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(292, 266)
        Me.Name = "Form1"
        Me.Text = "Form1"

    End Sub

#End Region

    Dim toolTip1 As New ToolTip

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        ' Set up the delays for the ToolTip.
        toolTip1.AutoPopDelay = 5000
        toolTip1.InitialDelay = 1000
        toolTip1.ReshowDelay = 500
        ' Force the ToolTip text to be displayed whether or not the form is active.
        toolTip1.ShowAlways = True

        ' Set up the ToolTip text for the Button and Checkbox.
        toolTip1.SetToolTip(Me.ListBox1, "My checkBox1")

    End Sub

    Private Sub ListBox1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles ListBox1.MouseMove
            Dim pt As New System.Drawing.Point(e.X, e.Y)
            'Dim s As String = CStr(ListBox1.GetChildAtPoint(pt).Text)
            toolTip1.SetToolTip(ListBox1, ListBox1.Items(e.Y Mod 12).ToString)
        End Try
    End Sub
End Class

I am not completely happy with this solution, but it will point you in the right direction.
You can see the commented line
Dim s As String = CStr(ListBox1.GetChildAtPoint(pt).Text)

I would have assumed that line would return the correct string, but when I tried it out, GetChildAtPoint returned Nothing.

e.Y Mod 12 will kind of work if your font size is set to 12 points.


Just checked and the font size is definitely smaller than 12.
Anyhow, this should be pointing you in the right direction!

GetChildAtPoint returns a child control, not the item under the mouse pointer. you can get it with the IndexFromPoint method:

    Private Sub ListBox1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles ListBox1.MouseMove
            Dim pt As New System.Drawing.Point(e.X, e.Y)
            Dim s As String = CStr(ListBox1.Items(ListBox1.IndexFromPoint(pt)))
            toolTip1.SetToolTip(ListBox1, s)
        End Try
    End Sub

this works very well

the edge
> this works very well

It certainly does!

LordSauceAuthor Commented:
Thanks edge, but that only exists for listboxes, not list views!

Each item in my list has an icon, which (AFAIK) rules the listbox out.

Something similar for the listview would be great though...

Thanks also Dabas - will continue playing with your code!
Add this to the above code:

   Private Sub ListView1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles ListView1.MouseMove
            Dim pt As New System.Drawing.Point(e.X, e.Y)
            Dim lv As ListView = CType(sender, ListView)
            'Dim li As ListViewItem = lv.GetItemAt(e.X, e.Y)
            toolTip1.SetToolTip(ListView1, lv.GetItemAt(e.X, e.Y).Text)
        End Try
    End Sub


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LordSauceAuthor Commented:
This is what I've ended up using.

Storing the last available tooltip at the form level prevents the tooltip moving with the mouse - the code to set the tooltip is only fired once each time an individual listitem is entered, so the tooltip is only displayed once.

I'm also testing the length of the item to see whether a tooltip is required - I only want to display it if the text of the item is partly hidden. Because of the icon being displayed, it's necessary to adjust the width of the list slightly - 16 pixels seems to work fine.

Thanks again for your help!


Private Sub lvwAvailable_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles lvwAvailable.MouseMove

        Dim itmTemp As ListViewItem = lvwAvailable.GetItemAt(e.X, e.Y)

        ' check mouse is over a list item
        If (Not IsNothing(itmTemp)) Then

            ' check whether tooltip has already been displayed since entering the item
            If (Not (itmTemp.Text.Equals(strLastAvailableTooltip))) Then

                Dim g As Graphics = CreateGraphics()

                ' check whether tooltip is required
                ' only necessary if item not fully visible (width - 16 to take icon into account)
                If g.MeasureString(itmTemp.Text, itmTemp.Font).Width > lvwAvailable.Width - 16 Then
                    ttpToolTip.SetToolTip(lvwAvailable, itmTemp.Text)
                    strLastAvailableTooltip = itmTemp.Text
                    ttpToolTip.SetToolTip(lvwAvailable, String.Empty)
                    strLastAvailableTooltip = String.Empty
                End If
            End If
        End If

    End Try

End Sub
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