AttachDebugger.cs

using System;
using System.Runtime.InteropServices;
using System.Threading;
using System.Threading.Tasks;
using System.Linq;
using System.Collections.Generic;
using EnvDTE;

namespace Common
{
    [ComImport, Guid("00000016-0000-0000-C000-000000000046"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    public interface IOleMessageFilter
    {
        [PreserveSig]
        int HandleInComingCall(int dwCallType, IntPtr hTaskCaller, int dwTickCount, IntPtr lpInterfaceInfo);

        [PreserveSig]
        int RetryRejectedCall(IntPtr hTaskCallee, int dwTickCount, int dwRejectType);

        [PreserveSig]
        int MessagePending(IntPtr hTaskCallee, int dwTickCount, int dwPendingType);
    }

    public class MessageFilter : IOleMessageFilter
    {
        private const int Handled = 0, RetryAllowed = 2, Retry = 99, Cancel = -1, WaitAndDispatch = 2;

        int IOleMessageFilter.HandleInComingCall(int dwCallType, IntPtr hTaskCaller, int dwTickCount, IntPtr lpInterfaceInfo)
        {
            return Handled;
        }

        int IOleMessageFilter.RetryRejectedCall(IntPtr hTaskCallee, int dwTickCount, int dwRejectType)
        {
            return dwRejectType == RetryAllowed ? Retry : Cancel;
        }

        int IOleMessageFilter.MessagePending(IntPtr hTaskCallee, int dwTickCount, int dwPendingType)
        {
            return WaitAndDispatch;
        }

        public static void Register()
        {
            CoRegisterMessageFilter(new MessageFilter());
        }

        public static void Revoke()
        {
            CoRegisterMessageFilter(null);
        }

        private static void CoRegisterMessageFilter(IOleMessageFilter newFilter)
        {
            IOleMessageFilter oldFilter;
            CoRegisterMessageFilter(newFilter, out oldFilter);
        }

        [DllImport("Ole32.dll")]
        private static extern int CoRegisterMessageFilter(IOleMessageFilter newFilter, out IOleMessageFilter oldFilter);
    }

    public static class AttachDebugger
    {
        public static void ToProcess(int processId)
        {
            MessageFilter.Register();
            var process = GetProcess(processId);
            if (process != null)
            {
                process.Attach();
                Console.WriteLine("Attached to {0}", process.Name);
            }
            MessageFilter.Revoke();
        }
        private static Process GetProcess(int processID)
        {
            var dte = (DTE)Marshal.GetActiveObject("VisualStudio.DTE.12.0");
            var processes = dte.Debugger.LocalProcesses.OfType<Process>();
            return processes.SingleOrDefault(x => x.ProcessID == processID);
        }
    }
}