= Creating COM Library =

  * Create a new Class Library project (Eg: MyLib). Start VS2010 as administrator in order to register types and assemblies.
  * Interface:
    * Add to the file:<code csharp>using System.Runtime.InteropServices;</code>
    * Add a new interface to the project:<code csharp>public interface IMyLauncher
{
   void launch();
}</code>
    * Add the attributes ''InterfaceType'', ''Guid'' to the interface. Generate a Guid using Tools > Generate GUID. <code csharp>
[InterfaceType(ComInterfaceType.InterfaceIsDual)]
[Guid("F207154F-C7E9-42B7-92BA-D6C4DA4D0A55")]</code>
  * Class:
    * Add a class that implement the interface.<code csharp>
public class MyLauncher: IMyLauncher
{
    public void launch()
    {
    }
}</code>
    * Add the attributes ''ClassInterface'', ''Guid'', ''ProgId'' to the interface. Generate a Guid using Tools > Generate GUID. <code csharp>
[ClassInterface(ClassInterfaceType.None)]
[Guid("0BE40A98-FCAC-432D-B0B6-999B42A28E48")]
[ProgId("MyLib.MyLauncher")]</code>
    * ''ProgId'' convention is ''{namespace}.{class}''
  * Activate COM and register it:
    * In Project Properties (Alt-Enter) > Application > Assembly Information, check "Make Assembly COM-Visible". Alternatively, In the folder MyLib > Properties > AssemblyInfo, set ''ComVisible'' to true.
    * In Project Properties (Alt-Enter) > Build > Output, and check "Register for COM interop".
    * Build the project. This will register the COM object.
    * Alternatively, manually register COM object:<code>C:\>"%Windir%\Microsoft.NET\Framework\v4.0.30319\regasm.exe" /codebase MyLib.dll</code>

Now the COM object is available to be called by its ''ProgID''.
== Example ==
Example class for COM:
<code csharp>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System.Runtime.InteropServices;

namespace MyLib
{

    [InterfaceType(ComInterfaceType.InterfaceIsDual), Guid("XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX")]
    public interface IMyLauncher
    {
        void launch();
    }

    [ClassInterface(ClassInterfaceType.None), Guid("YYYYYYYY-YYYY-YYYY-YYYY-YYYYYYYYYYY"), ProgId("MyLib.MyLauncher")]
    public class MyLauncher: IMyLauncher
    {
        private string path = null;

        public void launch()
        {
            Console.WriteLine("Hello, World, from a COM object");

        }

    }
}
</code>

Example how to call COM object using VB script:
<code vb>
set obj = createObject("PSMyLib.PSMyLauncher") obj.launch()
</code>

Output:
<code>
Hello, World, from a COM object
</code>

== References ==

  * [[http://stackoverflow.com/questions/3360160/how-do-i-create-an-activex-com-in-c]]
  * [[http://www.codeproject.com/Articles/12673/Calling-Managed-NET-C-COM-Objects-from-Unmanaged-C]]