What are the contents of the :ms-properties alternate data stream?
See the question and my original answer on StackOverflowThey are just serialized Windows properties. You can write and read these files (as streams) using builtin Windows implementation of IPropertyStore, for example using the PSCreateMemoryPropertyStore function
Here is a small sample console app that creates a test.props
file with one property of string type:
#include <windows.h>
#include <atlbase.h>
#include <atlcom.h>
#include <propsys.h>
#include <propkey.h>
#include <propvarutil.h>
// some COM error handling useful macros
#define WIDEN2(x) L ## x
#define WIDEN(x) WIDEN2(x)
#define __WFILE__ WIDEN(__FILE__)
#define SBTRACE wprintf
#define CHECKHR(expr) {hr=(expr);if(FAILED(hr)){ SBTRACE(L"HR FAILED line:%u file:%s\n", __LINE__, __WFILE__); goto cleanup; } }
#define HR HRESULT hr=S_OK;
int main()
{
HR;
PROPVARIANT pv;
PropVariantInit(&pv);
CoInitialize(NULL);
{
CComPtr<IPropertyStore> ps;
CComPtr<IPersistStream> pstream;
CComPtr<IStream> stream;
// create the in-memory store
CHECKHR(PSCreateMemoryPropertyStore(IID_PPV_ARGS(&ps)));
// define some PROPVARIANT value (here it's a string)
CHECKHR(InitPropVariantFromString(L"hello world", &pv));
// any property key would work
CHECKHR(ps->SetValue(PKEY_ItemNameDisplay, pv));
// get IPersistStream to be able to load or write
CHECKHR(ps->QueryInterface(&pstream));
// create a file stream
CHECKHR(SHCreateStreamOnFileEx(L"test.props", STGM_WRITE | STGM_CREATE, 0, TRUE, nullptr, &stream));
// this sample only saves, but you can load from an existing stream
CHECKHR(pstream->Save(stream, TRUE));
}
cleanup:
PropVariantClear(&pv);
CoUninitialize();
return 0;
}
Here is the result: