调用CreateWindow()函数WinApi时出现错误1813

问题描述

我是C ++和WinApi的新手.我无法在WinApi中创建一个简单的窗口. CreateWindow()函数返回null. GetLastError()函数返回错误1813.但是在创建窗口之前，GetLastError()返回0.对不起，我的英语.这是我的完整代码:

#include <Windows.h>

LRESULT CALLBACK WndProc(HWND hWnd, UINT Message, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine, int nCmdShow)
{
 LPCWSTR szWindowClass = TEXT("WndClass");
 LPCWSTR szTitle = TEXT("Main window");
 DWORD dwError;

 WNDCLASS wc;
 wc.style = CS_OWNDC;
 wc.hInstance = hInstance;
 wc.cbClsExtra = 0;
 wc.cbWndExtra = 0;
 wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
 wc.hCursor = LoadCursor(NULL, IDC_ARROW);
 wc.hIcon = LoadIcon(NULL,IDI_APPLICATION);

 wc.lpfnWndProc = WndProc;
 wc.lpszClassName = szWindowClass;
 wc.lpszMenuName = L"MenuName";
 dwError = GetLastError(); //0

 RegisterClass(&wc);
 dwError = GetLastError();//0


 HWND hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
    CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);//NULL

 dwError = GetLastError();//1813 =(
 return 0;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
 return 0;
}

解决方案

首先，您的错误处理错误.文档告诉您仅在CreateWindow失败时才调用GetLastError.并且CreateWindow失败由返回值NULL指示.调用GetLastError之前必须检查CreateWindow的返回值.请确保您仔细阅读文档. >

您在调用RegisterClass时犯了完全相同的错误.为了您的辩护，这是Win32程序员最常犯的错误.

错误代码1813是ERROR_RESOURCE_TYPE_NOT_FOUND. 文档说:

同样，一旦您知道要看的地方，就可以通过阅读文档来学习此信息.

这意味着CreateWindow试图查找文件中不存在的资源.也许您没有设法链接菜单资源.

您的窗口操作也有问题.应该是:

LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
    return DefWindowProc(hWnd, Msg, wParam, lParam);
}

当您开始为某些消息添加定制处理时，请确保您仍对其他消息调用DefWindowProc.

I'm new in C++ and WinApi. I can't create a simple window in WinApi. CreateWindow() function returns null. GetLastError() func returns error 1813.But before creating window GetLastError() returns 0. Sorry for my English. Here is my full code:

#include <Windows.h>

LRESULT CALLBACK WndProc(HWND hWnd, UINT Message, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine, int nCmdShow)
{
 LPCWSTR szWindowClass = TEXT("WndClass");
 LPCWSTR szTitle = TEXT("Main window");
 DWORD dwError;

 WNDCLASS wc;
 wc.style = CS_OWNDC;
 wc.hInstance = hInstance;
 wc.cbClsExtra = 0;
 wc.cbWndExtra = 0;
 wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
 wc.hCursor = LoadCursor(NULL, IDC_ARROW);
 wc.hIcon = LoadIcon(NULL,IDI_APPLICATION);

 wc.lpfnWndProc = WndProc;
 wc.lpszClassName = szWindowClass;
 wc.lpszMenuName = L"MenuName";
 dwError = GetLastError(); //0

 RegisterClass(&wc);
 dwError = GetLastError();//0


 HWND hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
    CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);//NULL

 dwError = GetLastError();//1813 =(
 return 0;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
 return 0;
}

解决方案

First of all, your error handling is wrong. The documentation tells you to call GetLastError only if CreateWindow failed. And CreateWindow failure is indicated by a return value of NULL. You must check the return value of CreateWindow before calling GetLastError. Please make sure you read the documentation carefully.

You make the exact same mistake in your call to RegisterClass. In your defence, this is the most common mistake made by novice Win32 programmers.

Error code 1813, is ERROR_RESOURCE_TYPE_NOT_FOUND. The documentation says:

Again, you can learn this information by reading the documentation, once you know where to look.

What this means is that CreateWindow is trying to find a resource that is not present in the file. Perhaps you did not manage to link a menu resource.

Your window procedure is also defective. It should be:

LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
    return DefWindowProc(hWnd, Msg, wParam, lParam);
}

When you start to add bespoke handling for certain messages, ensure that you still call DefWindowProc for any other messages.

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