在框架 4.0 的 ListView 第一行上显示工具提示

Question

我有一个使用 VB.Net 在 Framework 2.0 中开发的 WinForm 应用程序，它在所有 ListView 对象上使用事件 MouseMove 来在 ListViews 的第一行显示 ToolTip 文本 - 因为这是不可能的据我所知，在没有第三方工具的情况下在 ColumnHeader 上有工具提示。

问题在于，自从我将应用程序转换为 Framework 4.0 后，这个“技巧”不起作用，并且不再显示工具提示。

有谁知道在 ListView ColumnHeaders 上显示工具提示的解决方案，或者更好的方法？

这是我的代码 sn-p：

Private Sub ShowTooltip(ByVal sender As Object, ByVal e As MouseEventArgs) 
    Handles myListView.MouseMove
  Dim iColumn As System.Int32 = FindListViewColumnHeader(e.X, e.Y)
  If Me.myListView.Columns.Count > 0 AndAlso iColumn >= 0 AndAlso
     iColumn <= Me.myListView.Columns.Count - 1 Then
         Me.myToolTip.Active = True
         Me.myToolTip.UseAnimation = True
         Me.myToolTip.UseFading = True
         Me.myToolTip.AutomaticDelay = 10000
         Me.myToolTip.AutoPopDelay = 10000
         Me.myToolTip.InitialDelay = 0
         Me.myToolTip.ReshowDelay = 2000

         Dim sTooltipText As System.String = SomeText(...)
         If sTooltipText <> DirectCast(Me.myToolTip.Tag, System.String) Then
                 Me.myToolTip.Tag = sTooltipText
                 Me.myToolTip.SetToolTip(Me.myListView, sTooltipText)
         End If
  Else
         Me.myToolTip.Active = False
  End If
End Sub

Protected Overridable Function FindListViewColumnHeader(ByVal X As System.Int32, 
       ByVal Y As System.Int32) As System.Int32
   If Y > 20 And Y < 40 Then
       Dim iCount As System.Int32
       Dim iLeft As System.Int32
       For iCount = 0 To myListView.Columns.Count - 1
           iLeft = iLeft + myListView.Columns(iCount).Width
           If X <= iLeft Then
               Return iCount
               Exit For
           End If
       Next
       Return iCount
   Else
       Return -1
   End If
End Function

注意：myToolTip 是

Friend WithEvents myToolTip As System.Windows.Forms.ToolTip

而 myListView 是

Protected WithEvents myListView As System.Windows.Forms.ListView

请注意，正如问题中所建议的： How to set tooltip for a ListviewItem、ShowItemToolTips 已设置为 True。

Answer 1

您可以获取标题列的句柄并将其子类化：

<DllImport("user32.dll", SetLastError:=True)> _
Private Shared Function SetWindowLong(ByVal hWnd As IntPtr, ByVal nIndex As Integer, ByVal newProc As Win32WndProc) As IntPtr

End Function

<DllImport("user32.dll")> _
Private Shared Function CallWindowProc(lpPrevWndFunc As IntPtr, hWnd As IntPtr, Msg As UInteger, wParam As Integer, lParam As Integer) As Integer
End Function

<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Shared Function SendMessage(ByVal hWnd As IntPtr, ByVal Msg As UInteger, ByVal wParam As Integer, ByVal lParam As Integer) As IntPtr
End Function

Private Delegate Function Win32WndProc(ByVal hWnd As IntPtr, ByVal Msg As UInteger, ByVal wParam As Integer, ByVal lParam As Integer) As Integer

Private Const GWL_WNDPROC As Integer = -4
Private Const WM_LBUTTONDOWN As Integer = &H201
Private Const WM_MOUSEMOVE As Integer = &H200

Private oldWndProc As IntPtr = IntPtr.Zero
Private newWndProc As Win32WndProc = Nothing

Private Sub SubclassHWnd(ByVal hWnd As IntPtr)
    'hWnd is the window you want to subclass...,
    'create a new delegate for the new wndproc
    newWndProc = New Win32WndProc(AddressOf MyWndProc)
    'subclass
    oldWndProc = SetWindowLong(hWnd, GWL_WNDPROC, newWndProc)
End Sub

Private Function MyWndProc(ByVal hWnd As IntPtr, ByVal Msg As UInteger, ByVal wParam As Integer, ByVal lParam As Integer) As Integer

    Select Case Msg
        Case WM_LBUTTONDOWN
            'The lower 2 bytes of lParam are the x coordinate 
            'and the higher 2 bytes the y.
            ToolTip1.Show("My tooltip", ListView1, lParam And &HFFFF, (lParam >> 16) And &HFF, 2000)
            Exit Select
        Case Else
            Exit Select
    End Select

    Return CallWindowProc(oldWndProc, hWnd, Msg, wParam, lParam)
End Function

要对标头进行子类化，请使用：

    'LVM_GETHEADER = &H101F
    Dim hwndHeader As IntPtr = SendMessage(ListView1.Handle, &H101F, 0, 0)
    SubclassHWnd(hwndHeader)

为方便起见，我使用了WM_LBUTTONDOWN 事件。您可以使用WM_MOUSEMOVE 事件并检查鼠标所在的列等...并显示工具提示

子类化代码：Subclass an Unmanged Window in C#