How to use Marshal.getActiveObject() to get 2 instance of of a running process that has two processes open

Question

Currently my code uses

SurferApp = Marshal.GetActiveObject("Surfer.Application") as Surfer.Application

to get the running instance of a software called surfer, for the sake of simplicity we can replace Surfer to Word that everyone knows about. Now let's say I have 2 MS word application running and I want to get both of them using Marshal.GetActiveObject(), how can I get both the running instances and associate each with a separate object?

Answer 1

Marshal.GetActiveObject returns the first instance it finds on ROT (running object table). If you have more than one instance running with the same name/id, you have to get it directly from ROT.

A few links to start:

• https://web.archive.org/web/20110827063921/http://dotnet-snippets.de/dns/laufende-com-objekte-abfragen-SID526.aspx (German only)
• http://www.codeproject.com/Articles/17490/Running-Object-Table-Provider-in-NET-consumer-in-M
• http://www.codeproject.com/Articles/7984/Automating-a-specific-instance-of-Visual-Studio-NE

Answer 2

The accepted answer contains only links. I have extracted the shortest answer possible from the cited material. I give you a MarshalGetActiveObject function that works the same way the old Marshal.GetActiveObject did.

[DllImport("oleaut32.dll", PreserveSig = false)]
private static void GetActiveObject(ref Guid rclsid, IntPtr pvReserved, [MarshalAs(UnmanagedType.IUnknown)] out object ppunk)

[DllImport("ole32.dll")]
private static int CLSIDFromProgID([MarshalAs(UnmanagedType.LPWStr)] string lpszProgID, out Guid pclsid)

public static object MarshalGetActiveObject(string progId)
{
    Guid clsid;
    object obj = null;
    if (CLSIDFromProgID(progId, out clsid) == 0)
        GetActiveObject(ref clsid, IntPtr.Zero, out obj);

    return obj;
}