is there a better way of doing this code...

[benmartin101]

I have this code:

		private void markError(string errorString, System.Drawing.Color color)
		{
			int lastStrLoc = 0;
			int strLoc = 0;
			int errorStrLen = errorString.Length;
			while((strLoc = rtbResult.Find(errorString, lastStrLoc, RichTextBoxFinds.None)) != -1)
			{
				lastStrLoc = strLoc + 1;
				rtbResult.Select(strLoc, errorStrLen);
				rtbResult.SelectionColor = color;
			}
		}

It basically looks for the errorString and changes its text to red. Is there a better way of doing this? When there is over 1000 of the target string, it takes quite a long time.