using DirectShow in Winforms - winforms

Question

i could run the How To Play a File code sample in c++ win32 console application, but when i try to implement it by winforms i get these Link errors:
Error 2 error LNK2020: unresolved token (0A000016) IID_IMediaEvent
Error 3 error LNK2020: unresolved token (0A000017) IID_IMediaControl
and some more link errors .....
here is the code of the form:
#include <dshow.h>
#pragma comment(lib, "Strmiids.lib")
namespace Form1 {
using namespace System;
using namespace System::ComponentModel;
using namespace System::Collections;
using namespace System::Windows::Forms;
using namespace System::Data;
using namespace System::Drawing;
/// <summary>
/// Summary for Form1
/// </summary>
public ref class Form1 : public System::Windows::Forms::Form
{
public:
Form1(void)
{
InitializeComponent();
//
//TODO: Add the constructor code here
//
}
protected:
/// <summary>
/// Clean up any resources being used.
/// </summary>
~Form1()
{
if (components)
{
delete components;
}
}
private:
/// <summary>
/// Required designer variable.
/// </summary>
System::ComponentModel::Container ^components;
#pragma region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
void InitializeComponent(void)
{
this->SuspendLayout();
//
// Form1
//
this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
this->ClientSize = System::Drawing::Size(284, 262);
this->Name = L"Form1";
this->Text = L"Form1";
this->Load += gcnew System::EventHandler(this, &Form1::Form1_Load);
this->ResumeLayout(false);
}
#pragma endregion
private: System::Void Form1_Load(System::Object^ sender, System::EventArgs^ e)
{
IGraphBuilder *pGraph = NULL;
IMediaControl *pControl = NULL;
IMediaEvent *pEvent = NULL;
// Initialize the COM library.
HRESULT hr = CoInitialize(NULL);
// Create the filter graph manager and query for interfaces.
hr = CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER,
IID_IGraphBuilder, (void **)&pGraph);
hr = pGraph->QueryInterface(IID_IMediaControl, (void **)&pControl);
hr = pGraph->QueryInterface(IID_IMediaEvent, (void **)&pEvent);
// Build the graph. IMPORTANT: Change this string to a file on your system.
hr = pGraph->RenderFile(L"C:\\Example.avi", NULL);
if (SUCCEEDED(hr))
{
// Run the graph.
hr = pControl->Run();
if (SUCCEEDED(hr))
{
// Wait for completion.
long evCode;
pEvent->WaitForCompletion(INFINITE, &evCode);
// Note: Do not use INFINITE in a real application, because it
// can block indefinitely.
}
}
pControl->Release();
pEvent->Release();
pGraph->Release();
CoUninitialize();
}
};
}
How can i setup the build environment in winforms to do the DirectShow programming?
im using windows SDK v7.1 And vc++ 2010

Answer 1

You are not getting a great diagnostic. The problem is that DirectShow is native code. But you are letting the compiler think it is okay to compile it in managed mode. Which works surprisingly well, until the linker takes a nosedive. You need to make it look like this:
#pragma once
#pragma managed(push, off)
#include <dshow.h>
#pragma managed(pop)
#pragma comment(lib, "strmiids.lib")
#pragma comment(lib, "ole32.lib")
// etc..
This probably generates a flurry of errors. Right-click the project in the Solution Explorer window, Properties, Configuration Properties, General. Change Common Language Runtime support from /clr:pure to /clr. This played a sample .avi file properly when I tried it. In a DirectShow window, not the form. The sample code was designed only to work in a console application. You should also remove the calls to CoInitialize and CoUninitialize, .NET already initializes COM. Improving the error handling is advisable. Consider embedding Windows Media Player instead.