使用System.Diagnostics.Stopwatch类。

Stopwatch sw = new Stopwatch();
sw.Start();

// Do some code.

sw.Stop();

// sw.ElapsedMilliseconds = the time your "do some code" took.

将基准测试代码放入实用程序类/方法中是很有用的。StopWatch类不需要在错误时被丢弃或停止。最简单的为动作计时的代码是

public partial class With
{
    public static long Benchmark(Action action)
    {
        var stopwatch = Stopwatch.StartNew();
        action();
        stopwatch.Stop();
        return stopwatch.ElapsedMilliseconds;
    }
}

示例调用代码

public void Execute(Action action)
{
    var time = With.Benchmark(action);
    log.DebugFormat(“Did action in {0} ms.”, time);
}

下面是扩展方法的版本

public static class Extensions
{
    public static long Benchmark(this Action action)
    {
        return With.Benchmark(action);
    }
}

以及示例调用代码

public void Execute(Action action)
{
    var time = action.Benchmark()
    log.DebugFormat(“Did action in {0} ms.”, time);
}

秒表的功能会更好(精度更高)。我还建议下载一款流行的分析器(DotTrace和ANTS是我用得最多的…免费试用的DotTrace功能齐全，不像其他一些唠叨)。

@Sean钱伯斯

供您参考，.NET Timer类不是用于诊断的，它以预设的时间间隔生成事件，如下(来自MSDN):

System.Timers.Timer aTimer;
public static void Main()
{
    // Create a timer with a ten second interval.
    aTimer = new System.Timers.Timer(10000);

    // Hook up the Elapsed event for the timer.
    aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);

    // Set the Interval to 2 seconds (2000 milliseconds).
    aTimer.Interval = 2000;
    aTimer.Enabled = true;

    Console.WriteLine("Press the Enter key to exit the program.");
    Console.ReadLine();
}

// Specify what you want to happen when the Elapsed event is 
// raised.
private static void OnTimedEvent(object source, ElapsedEventArgs e)
{
    Console.WriteLine("The Elapsed event was raised at {0}", e.SignalTime);
}

所以这并不能帮助你知道某件事花了多长时间，只是告诉你某段时间已经过去了。

计时器也作为一个控件在System.Windows.Forms…你可以在VS05/VS08的设计器工具箱中找到它

因为我不太关心精度，所以我最终比较了它们。我正在捕获网络上的大量数据包，我想在我收到每个数据包时放置时间。下面是测试500万次迭代的代码

    int iterations = 5000000;

    // Test using datetime.now
    {
        var date = DateTime.UtcNow.AddHours(DateTime.UtcNow.Second);

        var now = DateTime.UtcNow;

        for (int i = 0; i < iterations; i++)
        {
            if (date == DateTime.Now)
                Console.WriteLine("it is!");
        }
        Console.WriteLine($"Done executing {iterations} iterations using datetime.now. It took {(DateTime.UtcNow - now).TotalSeconds} seconds");
    }

    // Test using datetime.utcnow
    {
        var date = DateTime.UtcNow.AddHours(DateTime.UtcNow.Second);

        var now = DateTime.UtcNow;

        for (int i = 0; i < iterations; i++)
        {
            if (date == DateTime.UtcNow)
                Console.WriteLine("it is!");
        }
        Console.WriteLine($"Done executing {iterations} iterations using datetime.utcnow. It took {(DateTime.UtcNow - now).TotalSeconds} seconds");
    }

    // Test using stopwatch
    {
        Stopwatch sw = new Stopwatch();
        sw.Start();

        var now = DateTime.UtcNow;

        for (int i = 0; i < iterations; i++)
        {
            if (sw.ElapsedTicks == DateTime.Now.Ticks)
                Console.WriteLine("it is!");
        }
        Console.WriteLine($"Done executing {iterations} iterations using stopwatch. It took {(DateTime.UtcNow - now).TotalSeconds} seconds");
    }

输出结果为:

Done executing 5000000 iterations using datetime.now. It took 0.8685502 seconds 
Done executing 5000000 iterations using datetime.utcnow. It took 0.1074324 seconds 
Done executing 5000000 iterations using stopwatch. It took 0.9625021 seconds

总之，DateTime。如果您不太关心精度，UtcNow是最快的。这也支持了这个问题的答案https://stackoverflow.com/a/6986472/637142。

这不够专业:

Stopwatch sw = Stopwatch.StartNew();
PerformWork();
sw.Stop();

Console.WriteLine("Time taken: {0}ms", sw.Elapsed.TotalMilliseconds);

更可靠的说法是:

PerformWork();

int repeat = 1000;

Stopwatch sw = Stopwatch.StartNew();
for (int i = 0; i < repeat; i++)
{
   PerformWork();
}

sw.Stop();

Console.WriteLine("Time taken: {0}ms", sw.Elapsed.TotalMilliseconds / repeat);

在我的实际代码中，我将添加GC。收集调用以将托管堆更改为已知状态，并添加Sleep调用，以便在ETW配置文件中轻松分离不同的代码间隔。