WinApi 控件不显示在主窗口上

Question

您好，我有以下 win32 程序，并且我有一个未显示在屏幕上的 EDITTEXT 控件。本来应该在主窗口上绘制两个EDITTEXT控件，但是只显示一个，这是为什么呢？

完整代码

#include <windows.h>
#include <iostream>
#include "resource.h"
using namespace std;
const int BUFFERMAX = 512;
char server_ip[BUFFERMAX];
int port;


const char windclassname[] = "windowClass";

LRESULT CALLBACK WndProc(HWND hwnd,UINT msg,WPARAM wParam,LPARAM lParam);
INT_PTR CALLBACK AboutDialog(HWND hwnd,UINT msg,WPARAM wParam,LPARAM lParam);
INT_PTR CALLBACK ConnectWin(HWND hwnd,UINT msg,WPARAM wParam,LPARAM lParam);


int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nCmdShow){
    WNDCLASSEX parent_window;
    HWND hwnd;
    MSG msg;

    parent_window.cbSize = sizeof(WNDCLASSEX);
    parent_window.style = 0;
    parent_window.lpfnWndProc = WndProc;
    parent_window.cbClsExtra = 0;
    parent_window.cbWndExtra = 0;
    parent_window.hInstance = hInstance;
    parent_window.hIcon = LoadIcon(NULL,IDI_APPLICATION);
    parent_window.hCursor = LoadCursor(NULL,IDC_ARROW);
    parent_window.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
    parent_window.lpszMenuName = MAKEINTRESOURCE(ID_MENU);
    parent_window.lpszClassName = windclassname;
    parent_window.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

    //Registering the Class for use.
    if ( !RegisterClassEx(&parent_window)){
        MessageBox(NULL,"Could not Register WindowClass","Error",MB_OK);
        return 0;
    }

    //Creating the window
    hwnd = CreateWindowEx(WS_EX_CLIENTEDGE,windclassname,"UI test",WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,250,350,NULL,NULL,hInstance,NULL);
    if ( hwnd == NULL ){
        MessageBox(NULL,"Could not create window","Error",MB_OK);
        return 0;
    }

    ShowWindow(hwnd,nCmdShow);
    UpdateWindow(hwnd);

    while ( GetMessage(&msg,NULL,0,0) > 0 ) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;

}

LRESULT CALLBACK WndProc(HWND hwnd,UINT msg,WPARAM wParam,LPARAM lParam){
    switch (msg){
        case WM_CREATE:

            HWND chatbox_cntrl;
            HWND message_text;

            chatbox_cntrl = CreateWindowEx(WS_EX_CLIENTEDGE,"EDIT","",
                WS_CHILD | WS_VISIBLE | WS_VSCROLL | WS_HSCROLL | ES_MULTILINE | ES_AUTOVSCROLL | ES_AUTOHSCROLL,
                0,0,240,260,hwnd,(HMENU)CHATBOX,GetModuleHandle(NULL),NULL);

            message_text = CreateWindowEx(WS_EX_CLIENTEDGE,"EDIT","",
                WS_CHILD,0,270,240,10,hwnd,(HMENU)MESSAGETEXT,GetModuleHandle(NULL),NULL);

        break;
        case WM_COMMAND:
            switch(LOWORD(wParam)){
                case ID_MABOUT_INFO:
                    DialogBox(GetModuleHandle(NULL), MAKEINTRESOURCE(ID_MABOUT_INFO), hwnd,AboutDialog);
                break;

                case ID_MCONTROLS_CONNECT:
                    int ret = DialogBox(GetModuleHandle(NULL), MAKEINTRESOURCE(ID_MCONTROLS_CONNECT), hwnd,ConnectWin);
                break;
                case ID_MCONTROLS_EXIT:
                    DestroyWindow(hwnd);
                break;
            }
        break;
        case WM_CLOSE:
            DestroyWindow(hwnd);
        break;
        case WM_DESTROY:
            PostQuitMessage(0);
        break;
    }
    return DefWindowProc(hwnd,msg,wParam,lParam);

}

INT_PTR CALLBACK AboutDialog(HWND hwnd,UINT msg,WPARAM wParam,LPARAM lParam){
    switch (msg){
        case WM_CLOSE:
            EndDialog(hwnd,WM_CLOSE);
        break;
        default:
            return false;
    }
    return true;

}

INT_PTR CALLBACK ConnectWin(HWND hwnd,UINT msg,WPARAM wParam,LPARAM lParam){
    switch(msg){
        case WM_COMMAND:
            switch(wParam){
                case CONNECT_BUTTON:
                    int len = GetWindowTextLength(GetDlgItem(hwnd,EDITTEXT_CONNECT));
                    int recv = GetDlgItemText(hwnd,EDITTEXT_CONNECT,server_ip,len+1);
                    port = GetDlgItemInt(hwnd,EDITTEXT_PORT,NULL,false);
                    EndDialog(hwnd,CONNECT_BUTTON);
                break;
            }
        break;
        case WM_CLOSE:
            EndDialog(hwnd,WM_CLOSE);
        break;
        default:
            return false;
    }
    return true;
}

这是两个控件。

case WM_CREATE:

            HWND chatbox_cntrl;
            HWND message_text;

            chatbox_cntrl = CreateWindowEx(WS_EX_CLIENTEDGE,"EDIT","",
                WS_CHILD | WS_VISIBLE | WS_VSCROLL | WS_HSCROLL | ES_MULTILINE | ES_AUTOVSCROLL | ES_AUTOHSCROLL,
                0,0,240,260,hwnd,(HMENU)CHATBOX,GetModuleHandle(NULL),NULL);

            message_text = CreateWindowEx(WS_EX_CLIENTEDGE,"EDIT","",
                WS_CHILD,0,270,240,10,hwnd,(HMENU)MESSAGETEXT,GetModuleHandle(NULL),NULL);

        break;

Answer 1

消息文本窗口没有与第一个相同的样式标志。具体来说，它缺少WS_VISIBLE。这很可能是你的问题。

Answer 2

您在创建编辑窗口之前是否致电InitCommonControlsEx()？ CreateWindow() 是否返回有效的HWND？

INITCOMMONCONTROLSEX icc;
icc.dwSize = sizeof(icc);
// Load one of the intrinsic User32 control classes.
// The user controls include button, edit, static,
// listbox, combobox, and scrollbar. 
dwICC = ICC_STANDARD_CLASSES;
::InitCommonControlsEx(&icc);

Answer 3

您是否在使用 InitCommonControlsEx 加载控件之前对其进行了初始化？试试这个代码一。

int InitControls() {
    INITCOMMONCONTROLSEX iccx;

    iccx.dwSize = sizeof(INITCOMMONCONTROLSEX);
    iccx.dwICC = ICC_WIN95_CLASSES;

    InitCommonControlsEx(&iccx);
}

记得包含头文件 commctrl.h 和库 comctl32.dll

祝你好运！