如何使对话框中接收到WM_CHAR消息(Windows编程)

最新推荐文章于 2021-05-25 06:42:36 发布

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#windows #dialog #callback #command #winapi #编程

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博客指出对话框有时捕获不到WM_CHAR消息，如在对话框Edit控件键入内容时。对于MFC编程可重载PreTranslateMessage解决，而Windows编程利用API较麻烦。文中提供两种方法实现将Edit控件键入内容变为大写，代码均在VC6.0上通过。

我们大家都知道,对话框是有的时候捕获不到WM_CHAR消息的.比如,你想使对话框里的Edit控件所键入的全部变为大写.我们毫不犹豫的写到:

#include
//Declare the Dialog Procedure
BOOL CALLBACK DialogProc(HWND, UINT, WPARAM, LPARAM);

int WINAPI WinMain(
HINSTANCE hInstance, // handle to current instance
HINSTANCE hPrevInstance, // handle to previous instance
LPSTR lpCmdLine,      // pointer to command line
int nCmdShow          // show state of window
)
{
    int ret = DialogBoxParam(hInstance, MAKEINTRESOURCE(IDD_DIALOG1), NULL, DialogProc, 0);
return(ret != IDOK);
}

break;
case WM_CHAR:
  wParam=toupper(wParam);
  break;
case WM_COMMAND:
  switch(LOWORD(wParam)){
  case IDOK:
  case IDCANCEL:
   //Close the dialog
   EndDialog(hwndDlg, LOWORD(wParam));
  }
  return TRUE;
}
return FALSE;
}
很遗憾,我敢肯定地告诉你你将会失败,为什么,问题就是出在WM_CHAR上,你可以试一试,当你不把光标移动到Edit控件时,对话框可以捕获到
WM_CHAR消息,但是一旦你把光标移动到Edit控件时,就捕获不到WM_CHAR了.

出现了这种情况,有什么方法可以捕获到WM_CHAR呢?我想对于MFC编程,小Case了,只需重载PreTranslateMessage.
可是对于Windows编程,利用API来写有点麻烦,这里我提供2种方法来达到变为大写的目的.
1)捕获WM_CHAR消息,在这里其实不是对话框真正的捕获WMC_CHAR.多话不说,还是提供代码吧,大家自己去看.

#include
//Declare the Dialog Procedure
BOOL CALLBACK DialogProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK NewEditProc(HWND, UINT, WPARAM, LPARAM);

//Define a gloabal var
WNDPROC g_Edit;
int WINAPI WinMain(
HINSTANCE hInstance, // handle to current instance
HINSTANCE hPrevInstance, // handle to previous instance
LPSTR lpCmdLine,      // pointer to command line
int nCmdShow          // show state of window
)
{
    int ret = DialogBoxParam(hInstance, MAKEINTRESOURCE(IDD_DIALOG1), NULL, DialogProc, 0);
    return(ret != IDOK);
}

LRESULT CALLBACK NewEditProc (HWND hwnd, UINT message,
                             WPARAM wParam, LPARAM lParam)
{
TCHAR chCharCode;
switch (message)
{
case WM_CHAR:
  wParam=toupper(wParam);
  break;
}
return CallWindowProc (g_Edit, hwnd, message, wParam, lParam);
}

2)第二种方法有点土了,不过达到目的就是好方法.还是提供原代码吧.

#include
//Declare the Dialog Procedure
BOOL CALLBACK DialogProc(HWND, UINT, WPARAM, LPARAM);

BOOL CALLBACK DialogProc(
HWND hwndDlg, // handle to dialog box
UINT uMsg,     // message
WPARAM wParam, // first message parameter
LPARAM lParam // second message parameter
){
HWND hWndEdit;
switch (uMsg) {
case WM_INITDIALOG:
  hWndEdit = GetDlgItem(hwndDlg, IDC_EDIT1);
  return TRUE;

case WM_COMMAND:
  switch(LOWORD(wParam)){
  case IDC_EDIT1:
  if(HIWORD(wParam)==EN_CHANGE)
  {
   TCHAR szString[100]={0};
   GetDlgItemText(hwndDlg,IDC_EDIT1,szString,99);
   int nLen=0;
   int index=0;
   nLen=lstrlen(szString);
   for(index=0;index   {
    if(szString[index]<='z'&&szString[index]>='a')
    {
     szString[index]-=32;
    }
   }
         szString[nLen]=0;

      SendMessage(GetDlgItem(hwndDlg,IDC_EDIT1),WM_SETTEXT,(WPARAM)0,(LPARAM)(LPCSTR)szString);
         SendMessage(GetDlgItem(hwndDlg,IDC_EDIT1),EM_SETSEL,lstrlen(szString),lstrlen(szString));
         }
    break;
  case IDOK:
  case IDCANCEL:
   EndDialog(hwndDlg, LOWORD(wParam));
  }
  return TRUE;
}
return FALSE;
}
以上均在VC6.0上通过