Question

我用VB写了一个sendmessage的测试程序，向一个名为“测试窗体”的的窗体（vb.net编写），但不起作用

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
'Private Const vbKeyA As Long = &H65
Private Const WM_KEYDOWN = &H100
Const WM_ACTIVATE = &H6
Const WM_LBUTTONUP = &H202
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long

Private Sub Command1_Click()
Dim hwnd As Long
hwnd = FindWindow(vbNullString, "测试窗体")
If hwnd <> 0 Then
MsgBox "1"
SendMessage hwnd, WM_KEYDOWN, vbKeyB, 0
Else
MsgBox "2"
End If

以上为VB6编写的测试程序代码，接收信息的窗体是VB.NET,我向“测试窗体“发出一个按下B键的信息，测试窗体应该会弹出对话框，但是测试窗体没有任何反映，麻烦大家给我指示下这是怎么回事？

Answer 1

SendMessage hwnd, &H102, vbKeyB, 0

Answer 2

真实按下B键，VB.NET窗体有反应吗？特别是其处于后台的情况下

Answer 3

SendMessage hwnd, WM_KEYDOWN, vbKeyB, 0

SendMessage hwnd, WM_KEYUP, vbKeyB, 0