求教怎么后台向窗口发送消息

Question

我先用findwindow找到了hwnd然后PostMessage(hwnd,WM_CHAR,'2',0);
但是我用记事本来试验都无法成功键入字符

Answer 1

你要键入字符要查找的不只是窗体，找到窗体以后还要找到里面的编辑框组件，用spy++看一下记事本，记事本里面就只有一个编辑框，一个状态栏。
先通过FindWindow找到窗体的句柄，然后通过FindWindowEx找到记事本窗体里面的编辑框的句柄，向编辑框组件发送字符就能够显示
HWND formHandle=NULL;
HWND childHandle=NULL;
formHandle=FindWindow(NULL,"记事本窗体名字");
if(formHandle==NULL) return;
childHandle=FindWindowEx(formHandle,NULL,NULL,NULL);//看spy++，第一个子句柄就是编辑框，找到这个句柄，就可以发送消息了
if(childHandle==NULL) return;
PostMessage(childHandle,WM_CHAR,'2',0);//这里发送消息就能在记事本的编辑框里面显示了

Answer 2

WM_CHAR消息并不是都支持, 有可能需要发送WM_KEYDOWN  和WM_KEYUP才行

Answer 3

确保找到了正确的窗口句柄
BOOL SendCharToNotepand(UINT vKey)
{
  BOOL bRet = FALSE;
  HWND hNotePad = FindWindow(_T("Notepad"), NULL);
  HWND hEdit = FindWindowEx(hNotePad, NULL, _T("Edit"), NULL);
  if(hEdit)
  {
    bRet = ::PostMessage(hEdit, WM_CHAR, vKey, 0);
  }
  return bRet;
}  

Answer 4

keybd_event()/SendInput()模拟按键~

Answer 5

列子：//
LPARAM MakeKeyLparam1(int VirtualKey, int flag) 
{ 
    LPARAM s; 
    unsigned char firstByte; 
// if (flag == WM_KEYDOWN) firstByte = 0;
// else                    firstByte = 0xc0;    switch (flag)
    {// 16–23 Specifies the scan code. 
      case WM_KEYDOWN:    firstByte = 0;   break;// 0000 0000
      case WM_KEYUP:      firstByte = 0xC0;break;// 1100 0000
      case WM_CHAR:       firstByte = 0x20;break;// 0010 0000
      case WM_SYSKEYDOWN: firstByte = 0x20;break;
      case WM_SYSKEYUP:   firstByte = 0xE0;break;// 1110 0000
      case WM_SYSCHAR:    firstByte = 0xE0;break;// 1110 0000
    }
//
    int scanCode; 
    scanCode = MapVirtualKey(VirtualKey, 0); 
afxDump << VirtualKey << ";" << scanCode << "\n";
//
    unsigned char secondByte; 
    secondByte = scanCode & 0xff;     s = (firstByte << 24) | (secondByte << 16) | 0x0001; 
//
    return s; 
}
void CToNotePadDlg::OnButton1() 
{
// TODO: Add your control notification handler code here
HWND hwnd=::FindWindow("NotePad","无标题 - 记事本");
if( hwnd)
{
// ::BringWindowToTop(hwnd);
#if 0 // Alt+F
// keybd_event(VK_MENU,0,0,0);
// keybd_event('F',0,0,0);
// keybd_event('F',0,KEYEVENTF_KEYUP,0);
// keybd_event(VK_MENU,0,KEYEVENTF_KEYUP,0);
// CTRL+O
keybd_event(VK_CONTROL,0,0,0);
keybd_event('O',0,0,0);
keybd_event('O',0,KEYEVENTF_KEYUP,0);
keybd_event(VK_CONTROL,0,KEYEVENTF_KEYUP,0);
// ::PostMessage(hwnd, WM_COMMAND,MAKEWPARAM(2,BN_CLICKED),NULL);//打开“打开”对话框 //第2句
Sleep(100);
hwnd=::FindWindow(NULL,"打开");
// 1148 = 0x47C cmb13 ComboBoxEx32
HWND hCmb13 = ::GetDlgItem(hwnd,0x047C);
if(hCmb13)
{
Sleep(500);
::SendMessage(hCmb13,WM_SETTEXT,0,(LPARAM)"abc.txt");
}
#else // OK
//WM_SYSKEYDOWN 
//nVirtKey = (int) wParam;    // virtual-key code 
//lKeyData = lParam;          // key data
// Alt+F must
::PostMessage(hwnd, WM_SYSKEYDOWN, VK_MENU, MakeKeyLparam(VK_MENU,WM_SYSKEYDOWN));
::PostMessage(hwnd, WM_SYSKEYDOWN, 'F', MakeKeyLparam('F',WM_SYSKEYDOWN));
::PostMessage(hwnd, WM_CHAR, 'F', MakeKeyLparam('F',WM_CHAR));
::PostMessage(hwnd, WM_SYSKEYUP, 'F', MakeKeyLparam('F',WM_SYSKEYUP));
::PostMessage(hwnd, WM_KEYUP, VK_MENU, MakeKeyLparam(VK_MENU,WM_KEYUP));
// Ctrl + O
// ::PostMessage(hwnd, WM_SYSKEYDOWN, VK_CONTROL, MakeKeyLparam1(VK_CONTROL,WM_SYSKEYDOWN));
// ::PostMessage(hwnd, WM_SYSKEYDOWN, 'O', MakeKeyLparam1('O',WM_SYSKEYDOWN));
// ::PostMessage(hwnd, WM_CHAR, 'O', MakeKeyLparam1('O',WM_CHAR));
// ::PostMessage(hwnd, WM_SYSKEYUP, 'O', MakeKeyLparam1('O',WM_SYSKEYUP));
// ::PostMessage(hwnd, WM_KEYUP, VK_CONTROL, MakeKeyLparam1(VK_CONTROL,WM_KEYUP));
// ::PostMessage(hwnd, WM_COMMAND,MAKEWPARAM(2,BN_CLICKED),NULL);//“打开”对话框 
Sleep(110);
hwnd=::FindWindow(NULL,"打开");
// 1148 = 0x47C cmb13 ComboBoxEx32
HWND hCmb13 = ::GetDlgItem(hwnd,0x047C);
//
if(hCmb13)
{
Sleep(500);
::SendMessage(hCmb13,WM_SETTEXT,0,(LPARAM)"abc.txt");
}
#endif
}
}

Answer 6

进程间的通信，你可以发送广播消息，HWND_BROADCAST