VB.NET – How to set tooltips on the .NET ListView subkey

Private _timer As Timer
Private Sub Timer()
 If _timer Is Nothing Then
 _timer = New Timer
 _timer. Interval = 500
 AddHandler _timer.Tick, AddressOf TimerTick
 _timer.Start()
 End If
End Sub
Private Sub TimerTick(ByVal sender As Object, ByVal e As EventArgs)
 _timer.Enabled = False
End Sub

Protected Overrides Sub OnMouseMove(ByVal e As System.Windows.Forms.MouseEventArgs)
 If Not _timer. Enabled Then
 Dim item = Me.HitTest(eX, eY)
 If Not item Is Nothing AndAlso Not item.SubItem Is Nothing Then
 If item.SubItem.Text = "" Then
 Dim tip = New ToolTip
 Dim p = item.SubItem.Bounds
 tip.ToolTipTitle = "Status"
 tip.ShowAlways = True
 tip.Show("FOO" , Me, eX, eY, 1000)
 _timer.Enabled = True
 End If
 End If
 End If

 MyBase.OnMouseMove(e)
End Sub

case TTN_GETDISPINFO:
 ListViewHitTestInfo info = this.HitTest(this.PointToClient(Cursor.Position));
 if (info.Item != null && info.SubItem != null) {
 // Call some method of your own to get the tooltip you want
 String tip = this.GetCellToolTip(info.Item, info.SubItem); 
 if (!String.IsNullOrEmpty(tip)) {
 NativeMethods.TOOLTIPTEXT ttt = (NativeMethods.TOOLTIPTEXT)m.GetLParam(typeof(NativeMethods.TOOLTIPTEXT));
 ttt.lpszText = tip;
 if (this.Ri ghtToLeft == RightToLeft.Yes)
 ttt.uFlags |= 4;
 Marshal.StructureToPtr(ttt, m.LParam, false);
 return; // do not do normal processing
 }
 }
 break;

I am trying to set tooltip text for some subitems in the listview control. I cannot get the tooltip displayed.

Does anyone have any suggestions?

Private _timer As Timer
Private Sub Timer()
 If _timer Is Nothing Then
 _timer = New Timer
 _timer. Interval = 500
 AddHandler _timer.Tick, AddressOf TimerTick
 _timer.Start()
 End If
End Sub
Private Sub TimerTick(ByVal sender As Object, ByVal e As EventArgs)
 _timer.Enabled = False
End Sub

Protected Overrides Sub OnMouseMove(ByVal e As System.Windows.Forms.MouseEventArgs)
 If Not _timer. Enabled Then
 Dim item = Me.HitTest(eX, eY)
 If Not item Is Nothing AndAlso Not item.SubItem Is Nothing Then
 If item.SubItem.Text = "" Then
 Dim tip = New ToolTip
 Dim p = item.SubItem.Bounds
 tip.ToolTipTitle = "Status"
 tip.ShowAlways = True
 tip.Show("FOO" , Me, eX, eY, 1000)
 _timer.Enabled = True
 End If
 End If
 End If

 MyBase.OnMouseMove(e)
End Sub

< p>ObjectListView (an open source wrapper around .NET WinForms ListView) has built-in support for cell tooltips (yes, it does work in VB). You listen to a CellToolTip event, and you can do something like this (this is undoubtedly excessive ):

alt text http://i31.tinypic.com/20udbgo.png

If you don’t want to use ObjectListView, you need to inherit ListView and listen for WM_NOTIFY messages , And then in these messages, respond to the TTN_GETDISPINFO notification in a similar way:

case TTN_GETDISPINFO:
 ListViewHitTestInfo info = this.HitTest(this.PointToClient(Cursor .Position));
 if (info.Item != null && info.SubItem != null) {
 // Call some method of your own to get the tooltip you want
 String tip = this.GetCellToolTip(info.Item, info.SubItem); 
 if (!String.IsNullOrEmpty(tip)) {
 NativeMethods.TOOLTIPTEXT ttt = (NativeMethods.TOOLTIPTEXT)m.GetLParam(typeof(NativeMethods .TOOLTIPTEXT));
 ttt.lpszText = tip;
 if (this.RightToLeft == RightToLeft.Yes)
 ttt.uF lags |= 4;
 Marshal.StructureToPtr(ttt, m.LParam, false);
 return; // do not do normal processing
 }
 }
 break ;

Obviously, this is C#, not VB, but you get the idea.