Simple StopWatcher helper class to give you back a nicely formatted elapsed time.

StopwatchHelper.cs

using System;
using System.Diagnostics;

namespace PDFMerger.Helpers
{
    public static class StopwatchHelper
    {
        /// <summary>
        /// Returns the elapsed time of the stopwatch in a formatted string.
        /// </summary>
        /// <returns>A string with a customized output of the elapsed time</returns>
        public static string GetElapsedTime( Stopwatch stopWatch )
        {
            TimeSpan ts = stopWatch.Elapsed;

            string elapsedTime;

            if ( ts.Minutes > 0 ) 
                elapsedTime = String.Format( "{0:00} min. {1:00}.{2:00} sec.", ts.Minutes, ts.Seconds, ts.Milliseconds / 10 );
            else if ( ts.Seconds > 0 )
                elapsedTime = String.Format( "{0:00}.{1:00} sec.", ts.Seconds, ts.Milliseconds / 10 );
            else
                elapsedTime = string.Format( "{0} ms.", ts.Milliseconds );

            return elapsedTime;
        }
    }
}