Question

我用的是Visual Studio.Net 2005出现了如下问题:不能将参数 2 从“const char [7]”转换为“LPCWSTR”

#include <windows.h>

HINSTANCE hInst;
HWND hWnd;

ATOM MyRegisterClass(HINSTANCE hInstance);
BOOL InitInstance(HINSTANCE, int);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

int APIENTRY WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
MSG msg;

MyRegisterClass(hInstance);

if (!InitInstance (hInstance, nCmdShow))
{
return FALSE;
}

while( msg.message!=WM_QUIT )
{
if( PeekMessage( &msg, NULL, 0,0 ,PM_REMOVE) )
{
TranslateMessage( &msg );
DispatchMessage( &msg );
}
else
{

}
}

return msg.wParam;
}

ATOM MyRegisterClass(HINSTANCE hInstance)
{
WNDCLASSEX wcex;

wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = (WNDPROC)WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = NULL;
wcex.hCursor = NULL;
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = NULL;
wcex.lpszClassName = L"canvas";
wcex.hIconSm = NULL;

return RegisterClassEx(&wcex);
}

BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
hInst = hInstance;
char d[8]="Direct",*ds;
ds=d;
HWND hWnd = ::CreateWindow("canvas",ds, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

if (!hWnd)
{
return FALSE;
}

MoveWindow(hWnd,10,10,640,480,true);
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);

return TRUE;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}

d:\jaychou\gogamex1\try1\jaychou\jaychou\main.cpp(71) : error C2664: “CreateWindowExW”: 不能将参数 2 从“const char [7]”转换为“LPCWSTR”
与指向的类型无关；转换要求 reinterpret_cast、C 样式转换或函数样式转换

Answer 1

你把"canvas"换成 L"canvas"就可以了。

Answer 2

在 VC 中常量字符串应该用 _T() 来包围, 可以自动适应 ANSI/UNICODE 的工程:

CreateWindow(_T("canvas"), ...