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按照 Direct2D ( https://learn.microsoft.com/en-us/windows/win32/direct2d/direct2d-quickstart ) 的官方教程使用 Visual Studio 2019 创建示例项目。在 x86 中运行代码时，将平台更改为 x64 时一切正常，我收到一条错误消息:“异常抛出:读取访问冲突。在 SampleD2D.cpp 中。 (该行在下面的代码中被注释掉了)
错误是:
Exception thrown: read access violation.
this was 0xBB18F6E8.
LRESULT CALLBACK DemoApp::WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
LRESULT result = 0;
if (message == WM_CREATE)
{
LPCREATESTRUCT pcs = (LPCREATESTRUCT)lParam;
DemoApp* pDemoApp = (DemoApp*)pcs->lpCreateParams;
::SetWindowLongPtrW(
hwnd,
GWLP_USERDATA,
PtrToUlong(pDemoApp)
);
result = 1;
}
else
{
DemoApp* pDemoApp = reinterpret_cast<DemoApp*>(static_cast<LONG_PTR>(
::GetWindowLongPtrW(
hwnd,
GWLP_USERDATA
)));
bool wasHandled = false;
if (pDemoApp)
{
switch (message)
{
case WM_SIZE:
{
UINT width = LOWORD(lParam);
UINT height = HIWORD(lParam);
pDemoApp->OnResize(width, height); // throw the error!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
}
result = 0;
wasHandled = true;
break;
case WM_DISPLAYCHANGE:
{
InvalidateRect(hwnd, NULL, FALSE);
}
result = 0;
wasHandled = true;
break;
case WM_PAINT:
{
pDemoApp->OnRender();
ValidateRect(hwnd, NULL);
}
result = 0;
wasHandled = true;
break;
case WM_DESTROY:
{
PostQuitMessage(0);
}
result = 1;
wasHandled = true;
break;
}
}
if (!wasHandled)
{
result = DefWindowProc(hwnd, message, wParam, lParam);
}
}
return result;
}