c++ - 除非首先创建，否则首先创建的对话框将变得无响应？

Question

在创建完美运行的初始对话框后，我在按下“加入游戏”按钮时创建了另一个对话框。对话框已创建并成功显示，但我无法在编辑框中键入内容，甚至无法按下或退出对话框。有谁知道如何解决这个问题或为什么会发生？我通过在应用程序的主循环中创建和显示对话框来确保对话框本身不是问题。当我以这种方式创建它时，它工作得很好。那么为什么从另一个对话框创建时会出错？我的代码如下。

此代码用于每个对话框使用的 DLGPROC 函数。

#define WIN32_LEAN_AND_MEAN
#include "Windows.h"
#include ".\Controllers\Menu\MenuSystem.h"
#include ".\Controllers\Game Controller\GameManager.h"
#include ".\Controllers\Network\Network.h"
#include "resource.h"
#include "main.h"
using namespace std;
extern GameManager g;
extern bool men;
NET_Socket server;
extern HWND d;
HWND joinDlg;
char ip[64];

void JoinMenu(){
 joinDlg = CreateDialog(g_hInstance, MAKEINTRESOURCE(IDD_GETADDRESSINFO), NULL, (DLGPROC)GameJoinDialogPrompt);
 SetFocus(joinDlg);
// ShowWindow(joinDlg, SW_SHOW);
 ShowWindow(d, SW_HIDE);
}
LRESULT CALLBACK GameJoinDialogPrompt(HWND Dialogwindow, UINT Message, WPARAM wParam, LPARAM lParam){
 switch(Message){
  case WM_COMMAND:{ 
   switch(LOWORD(wParam)){
    case IDCONNECT:{
      GetDlgItemText(joinDlg, IDC_IP, ip, 63);
      if(server.ConnectToServer(ip, 7890, NET_UDP) == NET_INVALID_SOCKET){
       LogString("Failed to connect to server! IP: %s", ip);
       MessageBox(NULL, "Failed to connect!", "Error", MB_OK);
       ShowWindow(joinDlg, SW_SHOW);
       break;
      }
       }
     LogString("Connected!");
     break;
    case IDCANCEL:
     ShowWindow(d, SW_SHOW);
     ShowWindow(joinDlg, SW_HIDE);
     break;
   }
   break;
  }
  case WM_CLOSE:
   PostQuitMessage(0);
   break;
 }
 return 0;
}
LRESULT CALLBACK GameMainDialogPrompt(HWND Dialogwindow, UINT Message, WPARAM wParam, LPARAM lParam){
 switch(Message){
 case WM_PAINT:{
   PAINTSTRUCT ps;
   RECT rect;
   HDC hdc = GetDC(Dialogwindow);
      hdc = BeginPaint(Dialogwindow, &ps);
   GetClientRect (Dialogwindow, &rect);
   FillRect(hdc, &rect, CreateSolidBrush(RGB(0, 0, 0)));
      EndPaint(Dialogwindow, &ps);
      break;
      }
  case WM_COMMAND:{
   switch(LOWORD(wParam)){
    case IDC_HOST:
     if(!NET_Initialize()){
      break;
     }
     if(server.CreateServer(7890, NET_UDP) != 0){
      MessageBox(NULL, "Failed to create server.", "Error!", MB_OK);
      PostQuitMessage(0);
      return -1;
     }
     ShowWindow(d, SW_HIDE);
     break;
    case IDC_JOIN:{
     JoinMenu();
     }
     break;
    case IDC_EXIT:
     PostQuitMessage(0);
     break;
    default:
     break;
   }
   break;
  }
 return 0;
 }
}

我使用下面的代码调用第一个对话框

void EnterMenu(){
// joinDlg = CreateDialog(g_hInstance, MAKEINTRESOURCE(IDD_GETADDRESSINFO), g_hWnd, (DLGPROC)GameJoinDialogPrompt);//
 d = CreateDialog(g_hInstance, MAKEINTRESOURCE(IDD_SELECTMENU), g_hWnd, (DLGPROC)GameMainDialogPrompt);

}

默认情况下，对话框不是禁用的，而是默认可见的。一切都设置为在创建时处于事件状态，并且没有代码停用对话框中的项目或对话框本身。

Answer 1

首先，确保您为对话过程编写了正确的签名:

INT_PTR CALLBACK DialogProc(HWND hwndDlg, UINT uMsg, 
                            WPARAM wParam, LPARAM lParam);

(参见 http://msdn.microsoft.com/en-us/library/ms645469(v=VS.85).aspx)

因此，您的对话过程应该如下所示:

INT_PTR CALLBACK GameJoinDialogPrompt(HWND Dialogwindow, UINT Message,
                                      WPARAM wParam, LPARAM lParam)
    { /* ... */ }
INT_PTR CALLBACK GameMainDialogPrompt(HWND Dialogwindow, UINT Message,
                                      WPARAM wParam, LPARAM lParam)
    { /* ... */ }

那么您应该能够在没有警告或错误的情况下执行此操作:

void EnterMenu()
{     
    d = CreateDialog(g_hInstance, MAKEINTRESOURCE(IDD_SELECTMENU),
                     g_hWnd, &GameMainDialogPrompt);
    // Note the ampersand. Also note that no cast is needed. You should
    // not need to use a cast to pass in the address of the function.
}     

参见 http://blogs.msdn.com/oldnewthing/archive/2004/01/15/58973.aspx这就是为什么获得正确的函数签名极其重要的原因。

也就是说，您的 joinDlg 应该是一个模态对话框，因为它正在向用户请求信息:

void JoinMenu()
{
    // DialogBox() creates a modal dialog box. It "blocks" its owner until
    // it closes. On the other hand, CreateDialog() creates a non-modal
    // dialog box.
    joinDlg = DialogBox(g_hInstance, MAKEINTRESOURCE(IDD_GETADDRESSINFO),
        d, &GameJoinDialogPrompt);
    // Again, note the ampersand and the lack of a cast when passing in
    // the address of the dialog procedure. Also, the main dialog box is
    // serving as the owner of this dialog box.
} 

另请注意，对话框过程与 Windows 过程的不同之处在于，它们返回 TRUE 或 FALSE:TRUE 如果您的对话框过程已处理消息，否则为 FALSE。 (有一些违反此规则的“奇怪”消息，但您没有处理这些消息)

所以你的对话过程应该是这样的:

INT_PTR CALLBACK GameMainDialogPrompt(HWND Dialogwindow, UINT Message,
                                      WPARAM wParam, LPARAM lParam)
{ 
    switch(Message)
    { 
    case WM_PAINT:
        /* Do painting */
        return TRUE; // We handled the paint message
    case WM_COMMAND:
        switch(LOWORD(wParam))
        {
        case IDC_HOST:
            /* Do command */
            return TRUE; // We handled this particular command.
        case IDC_JOIN:
            /* Do command */
            return TRUE; // We handled this particular command.
        case IDC_EXIT:
            /* Do command */
            return TRUE; // We handled this particular command.
        }
        return FALSE; // The command wasn't handled.
    }
    return FALSE; // The message wasn't handled.
} 

对话过程不调用DefWindowProc()也不返回0!