Findwindow and SendMessage

问题

Hey all i am trying to figure out why this is not sending a ALT+F to notepad!

Private Declare Function FindWindow1 Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Const WM_KEYUP = &H101
Private Const WM_KEYDOWN = &H100
Private Const WM_SYSKEYDOWN = &H104

Private Sub Command_Click()
Dim parenthwnd As Long
Dim hwnd As Long

  parenthwnd = FindWindow1(vbNullString, "Untitled - Notepad")
  retvalue = SendMessage(parenthwnd, WM_SYSKEYDOWN, VK_MENU, 1&)
  retvalue = SendMessage(parenthwnd, WM_KEYDOWN, VK_F, 1&)
End Sub

I get a value for parenthwnd but not for any of the retvalue values (0).

What am i missing???

David

回答1:

You can try to send/post these messages all you want. Unfortunately they don't effect the return value of GetAsyncKeyState - which is what the system uses, while processing the VK_F message - to see if the alt is down.

As a result you can't fake keystrokes with modifiers to other applications using this mechanism.

To get around this, you need to use SendInput - but this requires that the application to receive the keystrokes is the foreground/focus window.

回答2:

I think this is the problem: you're sending your message to the frame around the notepad window, and need to send it to the menu window. Use your handle with FindWindowEx and the 32768 class name (that's a menu) to get the menu window, which is a child of the one you've got the handle to. Here are two pages: http://msdn.microsoft.com/en-us/library/ms633500(v=VS.85).aspx and http://msdn.microsoft.com/en-us/library/ms633574(VS.85).aspx#class_name that should help.

回答3:

Use Postmessage instead of Sendmessage

Public Const WM_SYSKEYDOWN = &H104

PostMessage hwnd, WM_SYSKEYDOWN, vbKeyF, 2 ^ 29 

'Simulates Alt + F (2^29 sets the 29 bit of lParam indicating Alt is being pressed.

来源：https://stackoverflow.com/questions/4011252/findwindow-and-sendmessage

标签

vb6

sendmessage

findwindow