在C++中,可以有以下两种办法
利用COM接口IThumbnailCache
文档链接:IThumbnailCache (thumbcache.h) - Win32 apps | Microsoft Learn
示例代码如下:
- VOID GetFileThumbnail(PCWSTR path)
- {
- HRESULT hr = CoInitialize(nullptr);
- IShellItem* item = nullptr;
- hr = SHCreateItemFromParsingName(path, nullptr, IID_PPV_ARGS(&item));
- IThumbnailCache* cache = nullptr;
- hr = CoCreateInstance(
- CLSID_LocalThumbnailCache,
- nullptr,
- CLSCTX_INPROC,
- IID_PPV_ARGS(&cache));
- WTS_CACHEFLAGS flags = WTS_LOWQUALITY;
- ISharedBitmap* shared_bitmap;
- hr = cache->GetThumbnail(
- item,
- 12*16,
- WTS_EXTRACT,
- &shared_bitmap,
- nullptr,
- nullptr);
- HBITMAP hbitmap = NULL;
- hr = shared_bitmap->GetSharedBitmap(&hbitmap);
- shared_bitmap->Release();
- cache->Release();
- CoUninitialize();
- //使用hbitmap,使用完成后调用DeleteObject
- DeleteObject(hbitmap);
- }
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前面我不停利用的这种方式,但是最近系统升级后,会报 Generic Error in GDI+
背面我升级成了下面这种方式
利用IShellItemImageFactory接口
文档链接:IShellItemImageFactory (shobjidl_core.h) - Win32 apps | Microsoft Learn
官方示例代码:Windows-classic-samples/Samples/Win7Samples/winui/shell/appplatform/UsingImageFactory/ImageFactorySample.cpp at main · microsoft/Windows-classic-samples · GitHub
- HRESULT hr = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED | COINIT_DISABLE_OLE1DDE);
- HBITMAP hbmp = NULL;
- if (SUCCEEDED(hr))
- {
- IShellItemImageFactory* pImageFactory;
- hr = SHCreateItemFromParsingName(path, NULL, IID_PPV_ARGS(&pImageFactory));
- if (SUCCEEDED(hr))
- {
- SIZE size = { 256, 256 }; //图像大小
- hr = pImageFactory->GetImage(size, SIIGBF_THUMBNAILONLY, &hbmp);
- pImageFactory->Release();
- }
- CoUninitialize();
- //使用hbmp,使用完成后调用DeleteObject
- DeleteObject(hbmp);
- }
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在C#中利用,可以直接nuget引用 WindowsAPICodePack-Shell 包
- PM> NuGet\Install-Package WindowsAPICodePack-Shell -Version 1.1.1
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然后用下面的代码就可以获取文件缩略图
- ShellFile shellFile = ShellFile.FromFilePath(filepath);
- Bitmap shellThumb = shellFile.Thumbnail.ExtraLargeBitmap;
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