COM Interop Presentation comments

&Agenda

=========================

•What is COM

•Why use COM

•C++ COM

•C# COM

•C++ Console calls C++ COM

•C# calls unmanaged C++

•Managed C++ calls C#

•Import C Plus Plus Dll in .NET

•Mapping type between C++ and C#

•Compiling COM

=========================

What is COM

ATL project

COM project

------ATLClass.h------

int

 

 

GetSelf(int x);

------ATLClass.cpp------

 

int

 

 

ATLClass::GetSelf(int x)

{

 

 

 

return x;

}

 

------CATLSimple.h------

 

 

 

 

 

int

 

 

GetSelf(int x)

{

 

 

return x;

}

STDMETHOD(GetSelf)(LONG x, LONG* y);

------CATLSimple.cpp------

 

STDMETHODIMP CATLSimple::GetSelf(LONG x, LONG* y)

{

 

 

 

// TODO: Add your implementation code here

*y=x;

 

 

 

return

S_OK;

------.c in COMPS project------

COM_i.c

COM_p.c

 

 

unmanaged: C++ console call C++ dll

 

 

 

 

 

 

 

 

 

 

#include "D:/COM/COM/COM_i.c"#include "D:/COM/COM/COM_i.h"int _tmain(int argc, _TCHAR* argv[]){IATLSimple * isobj=NULL;HRESULT hr=CoInitialize(NULL);if(SUCCEEDED(hr)){hr=CoCreateInstance(CLSID_ATLSimple,NULL,CLSCTX_INPROC_SERVER,IID_IATLSimple,(void **)&isobj);if(SUCCEEDED(hr)){long l;isobj->GetSelf(1, &l);cout<<l<<endl;isobj->Release();}else{cout<<"Failed."<<endl;}}CoUninitialize();int i;cin>>i;return 0;}

C# dll project

namespace CSharpClassLibrary{ public class CSharpClass { public int GetSelf(int x) { return x; } }}

C# console project

namespace CSharpConsole{ class Program { [DllImport("COM", EntryPoint = "GetSelf")] public static extern int GetSelf(int x); static void Main(string[] args) { Console.WriteLine(GetSelf(1)); Console.Read(); } }}

Managed: C++ calls C#

#include "stdafx.h"using namespace System;using namespace CSharpClassLibrary;int main(array<System::String ^> ^args){CSharpClass ^csc=gcnew CSharpClass();Console::WriteLine(csc->GetSelf(1)); Console::WriteLine(L"Hello World");Console::Read(); return 0;}

Unmanaged C++

extern "C" _declspec(dllexport) int GetSelf(int x){return x;}

•Component Object Model

•OO

•VB, C++,J++,C#...

•ONE Interface, Multiple Implement

Why use COM?

 Clipboard Technology

àDDE

àOLE1.0

àOLE2.0 (COM)

àDCOM

àActiveX

 

Advantages: CBD, Code Reusability, OOP, Communicate each, Network.

What is metadata 

Metadata stored information:

•Description of program set

•Flag(name, version, area, public key)

•Exported type

•Other program which this program set depends on.

•Running needed security permission

•Description of type

•Name, visibility, base, interface of implementation

•Member(method, column, property, event, nested type)

•Property

•Decorated type and members of other descriptive elements

Import C Plus Plus Dll in .NET

 Œ Load Dynamically

•[DllImport("kernel32.dll", EntryPoint = "LoadLibrary")]

       public static extern int LoadLibrary(

           [MarshalAs(UnmanagedType.LPStr)] string lpLibFileName);

•[DllImport("kernel32.dll", EntryPoint = "GetProcAddress")]

       public static extern IntPtr GetProcAddress(int hModule,

           [MarshalAs(UnmanagedType.LPStr)] string lpProcName);

•[DllImport("kernel32.dll", EntryPoint = "FreeLibrary")]

       public static extern bool FreeLibrary(int hModule);

 Œ Load Dynamically

// function pointer

delegate int Add(int a, int b);

 

//1. Dynamically load C++ Dll

int hModule = LoadLibrary(AppDomain.CurrentDomain.BaseDirectory + @"CppInterop.dll");

if (hModule == 0) return;

//2. Read function pointer

IntPtr intPtr = GetProcAddress(hModule, "Add");

//3. Encapsulate function pointer to delegate

Add addFunction = (Add)Marshal.GetDelegateForFunctionPointer(intPtr, typeof(Add));

 • Load Statically

•[DllImport("CppInterop", EntryPoint = "ReturnBool", ExactSpelling = false, CallingConvention = CallingConvention.Cdecl)]

•        public static extern bool ReturnBool(bool str);