C#

class IPCMsgHandler
{
	private Thread listenThread = new Thread(ListeningThreadFunc);

...

	public void Start()
	{
		listenThread.Start(this);
	}

	private static void ListeningThreadFunc(object data)
	{
		IPCMsgHandler helper = data as IPCMsgHandler;

		...

		//helper.OnMessage(); doesn't work...staying in current thread context

		MethodInvoker mi = new MethodInvoker(helper.OnMessage);
		mi.Invoke();

		...
	}
}

public class AutoCADApplication : IExtensionApplication
{
	IPCMsgHandler helper = null;

	public void Initialize()
	{
		// I have the right execution-context here
		this.helper = new IPCMsgHandler("AutoCAD-IPCServer", new IPCMsgHandler.MessageHandler(this.OnIPCMessage));
		this.helper.Start();
	}
	private void OnIPCMessage()
	{
		// I have the WRONG execution-context here
		return;
	}

sw1.Start(); 
for (int k = 0; k < 500; k++) 
{
  longWord.Remove(longWord.Length - 10, 10);
}
sw1.Stop(); 

buchstaben wrote:

another point is, that a test 3 (removing backwards) will run in 0ms (?!):

static class ExtMethod
    {
        public static StringBuilder SubString(this StringBuilder sr1, int startPos, int length)
        {
            StringBuilder randomString = new StringBuilder();
            char[] charArray = new char[length];
            sr1.CopyTo(startPos, charArray, 0, length);
            randomString.Append(charArray);
            return randomString;
        }
    }

// We know how long the output needs to be, so preallocate capacity
StringBuilder output = new StringBuilder(length);
 
for ( int i = 0; i < length; ++i )
{
   output.Append( sr1.Chars[i] );
}
 
return output;

if (this.SelectionStart < 4)
                {                    
                    //string text = this.Text;
                    //this.strYear = text.Substring(0, 4);
                    //int num = int.Parse(this.strYear) + 1;
                    //this.strYear = num.ToString();
                    //this.strDate = string.Format("{0}/{1}/{2}", this.strYear, this.strMonth, this.strDay);
                    //this.Text = this.strDate;
                    e.Handled = true;
                }

public static bool Extract(Bitmap b)
{
  BitmapData bmData = b.LockBits(new Rectangle(0,0, b.Width, b.Height),
    ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
  int stride = bmData.Stride;
  IntPtr scan0 = bmData.Scan0;
  unsafe
  {
    byte *p = (byte*)(void*)scan0;
    //... Extract the image here
    
  }
}