Library tutorials & articles

COM Interoperability in .NET Part 2

By G.Gnana Arun Ganesh, published on 12 Mar 2002
G.Gnana Arun Ganesh G.Gnana Arun Ganesh is the Administrator and the Founder of ARUN MICRO SYSTEMS (www.arunmicrosystems.netfirms.com). He has been programming in C++, Visual Basic, COM, Java and Microsoft Technologie...
Page 2 of 4
  1. Introduction
  2. The managed code
  3. Generating a Type Library
  4. The unmanaged code

The managed code

To illustrate COM type communication with managed code, Let us see an example
in which I create a C# class library which has a class named Calculatorwhich supports three methods named Add(),Subtract()and Hello(). Notice that we define another interface named Imuldiv.

namespace Simpleclasslib
{
  using System;
  using System.Runtime.InteropServices;

  public interface Imuldiv
  {
    int Multiply(int x,int y);
    int Division(int x,int y);
  }
  
  public class Calculator:Imuldiv
  {
    public Calculator(){}
    public int Add(int x,int y) {
      return x+y;
    }
    public int Subtract(int x,int y)
    {
      return x-y;
    }
    int Imuldiv.Multiply(int x,int y)
    {
      return x*y;
    }
    int Imuldiv.Division(int x,int y)
    {
      return x/y;
    }
    public string Hello(string strName)
    {
      string str ;
      str = "Hello " + strName ;
      return str ;
    }
  }
}

Once the managed code is written, the compilation process is the same as it would be for any other piece of managed code.

csc /out:Server.dll /target:library Calculator.cs

Now let us see the Server.dll in the ILDasm.exe.In that you can see the calculator class members and Imuldiv Interface members.

Related tags

.net

Comments

  1. charles_andrew
    10 Jun 2006 at 03:39

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  2. Roberto Gutierrez
    12 Apr 2006 at 01:07

    Hello, good news!!!

    I just figured out what was missing in what was reported in previous comment.

    In the Properties Pages of the .NET project, choosing "Configuration Properties" on the left panel, and then "Build", there is a switch labelled "Register for COM Interop", and of course it has to be set "ON", for all this to work as expected!!!!

    Well, let's keep working.!!!!

    Be well!!!!!

     

  3. Roberto Gutierrez
    08 Apr 2006 at 00:38

    Hello, G.Gnana Arun:

    Hi, good day, greetings from Mexico City.

    Well, this post is to commet I just tried your implementation, I created a .NET DLL with VB.NET, then followed the .TLB file, just as you specify in your article, but at the moment of using the library in a VB 6.0 project, using the reference to the .TLB file, as you dictate, just when the object is to be instantiated, I receive a Num 429 error, "ActiveX Object can´t be created". I include here the code for the class in VB.NET:

    Public

     Class cDotNetUtilsVB60

    Public Shared Function IsPositiveInfinity(ByVal pdblNum As Double) As Boolean

    Dim lnuNumTem As Double

    Return lnuNumTem.IsPositiveInfinity(pdblNum)

    End Function

    Public Shared Function IsNegativeInfinity(ByVal pdblNum As Double) As Boolean

    Dim lnuNumTem As Double

    Return lnuNumTem.IsNegativeInfinity(pdblNum)

    End Function

    End

     Class

    Can you figure out what I'm doing wrong???????

    Thanks in advance, be well

    Roberto Gutierrez R.

     

     

  4. Developer Fusion Bot
    01 Jan 1999 at 00:00

    This thread is for discussions of COM Interoperability in .NET Part 2.

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