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Showing long ListBox entries as a ToolTip
By Matt Vandenbush, matt_vandenbush@whbrady.com
Sometimes the data you want to display in a list is too long for the size of ListBox you can use. When this happens, you can use some simple code to display the ListBox entries as ToolTips when the mouse passes over the ListBox.

First, start a new VB project and add a ListBox to the default form. Then declare the SendMessage API call and the constant (LB_ITEMFROMPOINT) needed for the operation:

Option Explicit

注释：Declare the API function call.
Private Declare Function SendMessage _
Lib "user32" Alias "SendMessageA" _
(ByVal hwnd As Long, _
ByVal wMsg As Long, _
ByVal wParam As Long, _
lParam As Any) As Long
注释： Add API constant
Private Const LB_ITEMFROMPOINT = &H1A9

Next, add some code to the form load event to fill the ListBox with data:

Private Sub Form_Load()
注释：
注释： load some items in the list box
With List1
.AddItem "Michael Clifford Amundsen"
.AddItem "Walter P.K. Smithworthy, III"
.AddItem "Alicia May Sue McPherson-Pennington"
End With
注释：
End Sub

Finally, in the MouseMove event of the ListBox, put the following code:

Private Sub List1_MouseMove(Button As Integer, Shift As Integer, _
X As Single, Y As Single)
注释：
注释： present related tip message
注释：
Dim lXPoint As Long
Dim lYPoint As Long
Dim lIndex As Long
注释：
If Button = 0 Then 注释： if no button was pressed
  lXPoint = CLng(X / Screen.TwipsPerPixelX)
  lYPoint = CLng(Y / Screen.TwipsPerPixelY)
  注释：
  With List1
    注释： get selected item from list
    lIndex = SendMessage(.hwnd, _
    LB_ITEMFROMPOINT, _
    0, _
    ByVal ((lYPoint * 65536) + lXPoint))
    注释： show tip or clear last one
    If (lIndex >= 0) And (lIndex <= .ListCount) Then
      .ToolTipText = .List(lIndex)
    Else
      .ToolTipText = ""
    End If
  End With 注释：(List1)
End If 注释：(button=0)
注释：
End Sub