Use a Stopwatch to Profile Your Code

Use the System.Diagnostics.Stopwatch class.

While there are many extensive profiling packages out there (there is a profiler included in some editions of Visual Studio), sometimes you just need to time a known block of code with a stopwatch.

System.Diagnostics.Stopwatch timer = new System.Diagnostics.Stopwatch();
timer.Start();
Decimal total = 0;
int limit = 1000000;
for (int i = 0; i < limit; ++i)
{
    total = total + (Decimal)Math.Sqrt(i);
}
timer.Stop();
Console.WriteLine("Sum of sqrts: {0}",total);
Console.WriteLine("Elapsed milliseconds: {0}",
timer.ElapsedMilliseconds);
Console.WriteLine("Elapsed time: {0}", timer.Elapsed);

This produces the output:

Sum of sqrts: 666666166.45882210823608
Elapsed milliseconds: 282
Elapsed time: 00:00:00.2828692

A useful trick when you need to use the Stopwatch for debugging purposes is to utilize the IDisposable interface to automate the use of the stopwatch:

class AutoStopwatch : System.Diagnostics.Stopwatch, IDisposable
{
    public AutoStopwatch()
    {
        Start();
    }

    public void Dispose()
    {
        Stop();
        Console.WriteLine("Elapsed: {0}", this.Elapsed);
    }
}

Now you can take advantage of the using {} syntax:

using (new AutoStopwatch())
{
    Decimal total2 = 0;
    int limit2 = 1000000;
    for (int i = 0; i < limit2; ++i)
    {
        total2 = total2 + (Decimal)Math.Sqrt(i);
    }
}

Besides Start() and Stop(), there are also Reset(), which stops and sets Elapsed to 0, and Restart(), which sets Elapsed to 0, but lets timer continue running.