hWnd = CreateWindow()这句话为什么返回0啊？

[wx376752150]

#include<windows.h>

LRESULT WINAPI WindowProc(HWND HWnd,UINT message,WPARAM wParam,LPARAM lParam);

//Insert code for WinMain() here (Listing OFWIN_1)
//Listing OFWIN_1
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevINstance, LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX WindowClass;

static LPCTSTR szAppName= L"OFWin";
HWND hWnd;
MSG msg;

WindowClass.cbSize=sizeof(WNDCLASSEX);

//Redraw the window if the size changes
WindowClass.style = CS_HREDRAW | CS_VREDRAW;

//Define the message handling function
WindowClass.lpfnWndProc=WindowProc;

WindowClass.cbClsExtra=0;
WindowClass.cbWndExtra=0;

WindowClass.hInstance=hInstance;

//Set default application icon
WindowClass.hIcon = LoadIcon(0,IDI_APPLICATION);

//Set window cursor to be the standard arrow
WindowClass.hCursor = LoadCursor(0,IDC_ARROW);

//set gray brush for background color
//WindowClass.hbrBackground= static_cast<HBRUSH>(GetStockObject(GRAY_BRUSH));
WindowClass.hbrBackground = CreateSolidBrush(RGB(0,0,255));
WindowClass.lpszMenuName = 0;
WindowClass.lpszClassName= szAppName;
WindowClass.hIcon=0;

//now register our window class
RegisterClassEx(&WindowClass);

//now we can create the window
hWnd = CreateWindow(
szAppName,
L"a basic window the hard way",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
NULL,
NULL,
hInstance,
NULL);


ShowWindow(hWnd,SW_MAXIMIZE); //display the window
UpdateWindow(hWnd);

//The message loop
while(GetMessage(&msg,0,0,0)==TRUE)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}

return static_cast<int>(msg.wParam);
}



//Insert code for WindowProc() here (Listing OFWIN_2)
//Listing OFWIN_2
LRESULT WINAPI WindowProc(HWND hWnd,UINT message,WPARAM wParam ,LPARAM lParam)
{
HDC hDC;
PAINTSTRUCT PaintSt;
RECT aRect;

switch(message)
{
case WM_PAINT:
hDC = BeginPaint(hWnd,&PaintSt);

//Get upper left and lower right of client area
GetClientRect(hWnd,&aRect);

SetBkMode(hDC,TRANSPARENT);

//Now draw the text in window client area
DrawText(
hDC,
L"But,soft!what light through yonder window breaks?",
-1,
&aRect,
DT_SINGLELINE|DT_CENTER|DT_VCENTER);

EndPaint(hWnd,&PaintSt);
return 0;

case WM_DESTROY:
PostQuitMessage(0);
return 0;

default:
return DefWindowProc(hWnd,message,wParam,lParam);
}
}

[hazrael]

取一下错误值，看是什么

[ypb362148418]

贴出错误，你可以查查MSDN对这个函数返回值的讲解

[耍宝王]

请LZ你是用什么IDE啊？
static LPCTSTR szAppName= L"OFWin";
L"a basic window the hard way"
由于你的类名和窗口名都定义为宽字符
相应的你要用CreateWindowW
如果你的IDE或你没有启用UNICODE宏的话，那CreateWindow映射的将是CreateWindowA
你可以直接使用CreateWindowW
或者把类名和窗口名改为
static LPCTSTR szAppName= TEXT("OFWin");
TEXT("a basic window the hard way")
试试看

[kakam]

楼上说得很对楼上说得很对

[zero_226]

返回0也不是没有可能，hWnd是一个句柄，如果Createwindow函数调用失败，有可能就返回0，你可以仔细看下createwindow的返回值说明。

[耍宝王]

除了我说的，还有就是你的代码中
WindowClass.hIcon = LoadIcon(0,IDI_APPLICATION);
WindowClass.hIcon = 0;
这里应该是
WindowClass.hIconSm = 0;

下面是从Code::Blocks的工程模板中复制出来的，如果还不行，可以参考一下

#include <windows.h>

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

/*  Make the class name into a global variable  */
char szClassName[ ] = "CodeBlocksWindowsApp";

int WINAPI WinMain (HINSTANCE hThisInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR lpszArgument,
                     int nCmdShow)
{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */

    /* The Window structure */
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                 /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
    wincl.cbWndExtra = 0;                      /* structure or the window instance */
    /* Use Windows's default colour as the background of the window */
    wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;

    /* The class is registered, let's create the program*/
    hwnd = CreateWindowEx (
           0,                   /* Extended possibilites for variation */
           szClassName,         /* Classname */
           "Code::Blocks Template Windows App",       /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           544,                 /* The programs width */
           375,                 /* and height in pixels */
           HWND_DESKTOP,        /* The window is a child-window to desktop */
           NULL,                /* No menu */
           hThisInstance,       /* Program Instance handler */
           NULL                 /* No Window Creation data */
           );

    /* Make the window visible on the screen */
    ShowWindow (hwnd, nCmdShow);

    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }

    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}


/*  This function is called by the Windows function DispatchMessage()  */

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)                  /* handle the messages */
    {
        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
        default:                      /* for messages that we don't deal with */
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
}

[耍宝王]

刚才的排版有点问题，详细位置看这里
WindowClass.hIcon = LoadIcon(0,IDI_APPLICATION);

//Set window cursor to be the standard arrow
WindowClass.hCursor = LoadCursor(0,IDC_ARROW);

//set gray brush for background color
//WindowClass.hbrBackground= static_cast <HBRUSH>(GetStockObject(GRAY_BRUSH));
WindowClass.hbrBackground = CreateSolidBrush(RGB(0,0,255));
WindowClass.lpszMenuName = 0;
WindowClass.lpszClassName= szAppName;
WindowClass.hIcon=0; //是这里的有问题，应该WindowClass.hIconSm = 0;

[wx376752150]

引用 3 楼 pgplay 的回复:

请LZ你是用什么IDE啊？
static LPCTSTR szAppName= L"OFWin";
L"a basic window the hard way"
由于你的类名和窗口名都定义为宽字符
相应的你要用CreateWindowW
如果你的IDE或你没有启用UNICODE宏的话，那CreateWindow映射的将是CreateWindowA
你可以直接使用CreateWindowW
或者把类名和窗口名改为
static LPCTSTR szAppName= TEXT("OFWin");
TEXT("a basic window the hard way")
试试看

试过了，没用啊，还有解答吗

[耍宝王]

引用 9 楼 wx376752150 的回复:

大哥你说的对了，不过能告诉我这两者有啥区别吗？

hIcon 窗口类的图标（按Alt + Tab切换程序时看到的图标），如果hIconSm设为0，那它也是窗口左上角和任务栏上的图标
hIconSm 窗口类相关联的一个小图标，就是窗口左上角和任务栏上的图标，如果设为0，则自动搜索hIcon中相关的小图标

你可以设成：
WindowClass.hIcon = LoadIcon (NULL, IDI_QUESTION);//按Alt + Tab切换程序时看到的图标为问号
WindowClass.hIconSm = LoadIcon (NULL, DI_ERROR);//窗口左上角和任务栏上的图标为红叉
然后看看窗口打开后的左上角和任务栏上的图标，然后按Alt + Tab切换程序，看代表此程序的图标

[wx376752150]

引用 8 楼 pgplay 的回复:

WindowClass.hIcon=0; //是这里的有问题，应该WindowClass.hIconSm = 0;

大哥你说的对了，不过能告诉我这两者有啥区别吗？