方法一：
Private Sub Text1_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
If Button = 2 Then
Text1.Enabled = False
Text1.Enabled = True
PopupMenu mymenu
End If
End Sub
方法二：回调函数
module：
Option Explicit
Public OldWindowProc As Long ' 保存默认的窗口函数的地址
Public Const WM_CONTEXTMENU = &H7B ' 当右击文本框时，产生这条消息
Public Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long) As Long
Public Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal hWnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Public Function SubClass_WndMessage(ByVal hWnd As Long, ByVal Msg As Long, ByVal wp As Long, ByVal lp As Long) As Long
' 如果消息不是WM_CONTEXTMENU，就调用默认的窗口函数处理
If Msg <> WM_CONTEXTMENU Then
SubClass_WndMessage = CallWindowProc(OldWindowProc, hWnd, Msg, wp, lp)
Exit Function
End If
SubClass_WndMessage = True
End Function
窗体中：
Private Const GWL_WNDPROC = (-4)
Private Sub Text1_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
If Button = 1 Then Exit Sub
OldWindowProc = GetWindowLong(Text1.hWnd, GWL_WNDPROC) ' 取得窗口函数的地址
' 用SubClass_WndMessage代替窗口函数处理消息
Call SetWindowLong(Text1.hWnd, GWL_WNDPROC, AddressOf SubClass_WndMessage)
End Sub
Private Sub Text1_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
If Button = 1 Then Exit Sub
' 恢复窗口的默认函数
Call SetWindowLong(Text1.hWnd, GWL_WNDPROC, OldWindowProc)
PopupMenu mymenu
End Sub
如果不想弹出任何对话框，把 PopupMenu mymenu去掉（对第二种方法有效).
转载于:https://www.cnblogs.com/feima-lxl/archive/2008/05/03/1180505.html
