Managed C++/CLI

typedef	bool (APIENTRY *CB_UpdateStatus)(unsigned PercentComplete);

bool APIENTRY UpdateStatus(unsigned PercentComplete)
{
   printf("\r%d%%...", PercentComplete);
   return false;
}

typedef	bool (APIENTRY *CB_UpdateStatus)(unsigned PercentComplete, void* context);

bool APIENTRY UpdateStatus(unsigned PercentComplete, void* context)
{
   printf("\r%d%%...", PercentComplete);
   return false;
}

DLLAPI HRESULT APIENTRY NativeFileRead(size_t DataSize, BYTE* Data, CB_UpdateStatus UpdateStatus, void* context)

Wrapper::FileRead(UInt32 DataSize, String^ managedFileHandle, BackgroundWorker^ worker)

bool __stdcall UpdateStatus(unsigned PercentComplete, void* context)
{
   BackgroundWorker^ worker = static_cast<BackgroundWorker^>(&context);
   worker->ReportProgress(PercentComplete);
      //Console::Write("\r{0}...", PercentComplete);
   return false;
}

HRESULT Result = NativeFileRead(DataSize, Data, UpdateStatus, context);

delegate bool UpdateProgressDelegate(unsigned int, Object^);

UpdateProgressDelegate^ upd = gcnew UpdateProgressDelegate(UpdateStatus);
GCHandle gch = GCHandle::Alloc(upd);
IntPtr ip = Marshal::GetFunctionPointerForDelegate(upd);
CB_UpdateStatus update = static_cast<HD_CB_UpdateStatus>(ip.ToPointer());

Result = NativeFileRead(DataSize, Data, UpdateStatus &context);

alleyes wrote:

Is that what you are suggesting? How does the native callback return percentcomplete through a BGW? I still need a native callback that takes the two args. Not real clear then

typedef	bool (*CB_UpdateStatus)(unsigned PercentComplete);

HRESULT NativeFileRead(size_t DataSize, BYTE* Data, CB_UpdateStatus UpdateStatus)
{
	UpdateStatus(100);
	return 0;
}

bool UpdateStatus(unsigned PercentComplete)
{   
	printf("From native code: %d\r\n", PercentComplete);   
	return false;
}

ref class Test
{
private:
	BackgroundWorker^ worker;

public:
	delegate bool ManagedUpdateStatus(unsigned int);

	int FileRead(int dataSize, array<byte>^ data, ManagedUpdateStatus^ updateStatus, BackgroundWorker^ worker)
	{
		pin_ptr<ManagedUpdateStatus^> tmp =  &updateStatus;
		NativeFileRead(0, NULL, (CB_UpdateStatus)Marshal::GetFunctionPointerForDelegate(updateStatus).ToPointer());  

		return 0;
	}

	void Foo() 
	{
		worker = gcnew BackgroundWorker();
		worker->WorkerReportsProgress = true;
		worker->DoWork += gcnew DoWorkEventHandler(this, &Test::Worker_DoWork);
		worker->ProgressChanged  += gcnew ProgressChangedEventHandler(this, &Test::Worker_ProgressChanged);
		worker->RunWorkerAsync();
	}
	
	bool DoManagedUpdateStatus(unsigned int percentage)
	{
		worker->ReportProgress(percentage);
		return false;
	}

	void Worker_DoWork(Object^ sender, DoWorkEventArgs^ e)
	{
		FileRead(0, nullptr, gcnew ManagedUpdateStatus(this, &Test::DoManagedUpdateStatus), (BackgroundWorker^)sender);
	}

	void Worker_ProgressChanged(Object^ sender, ProgressChangedEventArgs^ e)
	{
		Console::WriteLine("From the worker thread : {0}", e->ProgressPercentage);
	}
};

int main(array<System::String ^> ^args)
{
	NativeFileRead(0, NULL, UpdateStatus);
	(gcnew Test())->Foo();
	Console::ReadKey();
	return 0;
}

alleyes wrote:

Isn't it possible to box a managed object and get a pointer to it?

struct MyStruct
{
   msclr::auto_gcroot<BackgroundWorker^> worker;
}

bool APIENTRY UpdateStatus(unsigned PercentComplete, void* Context)
{
   MyStruct* strct = context;
   strct->worker->ReportProgress(PercentComplete);
   return false;
}

typedef	bool (*CB_UpdateStatus)(unsigned PercentComplete, void* pContext);

HRESULT NativeFileRead(size_t DataSize, BYTE* Data, CB_UpdateStatus UpdateStatus, void* pContext)
{
	UpdateStatus(100, pContext);
	return 0;
}

struct MyStruct
{   
	auto_gcroot<BackgroundWorker^> worker;
};

int FileRead(int dataSize, array<byte>^ data, ManagedUpdateStatus^ updateStatus, BackgroundWorker^ worker)
{
  pin_ptr<ManagedUpdateStatus^> tmp =  &updateStatus;
  MyStruct myStruct;
  myStruct.worker = worker;
  NativeFileRead(0, NULL, (CB_UpdateStatus)Marshal::GetFunctionPointerForDelegate(updateStatus).ToPointer(), &myStruct);  
  return 0;
}

bool DoManagedUpdateStatus(unsigned int percentage, IntPtr pContext)
{
  MyStruct* pMyStruct = (MyStruct*)pContext.ToPointer();
  pMyStruct->worker->ReportProgress(percentage);
  return false;
}

alleyes wrote:

I wished more was covered on this topic in your book.

inayathussaintoori wrote:

i am sorry actually i am new to the codeproject. but now i got how to ask a question.
thanks a lot