Stopwatch 类

定义

public ref class Stopwatch

public class Stopwatch

type Stopwatch = class

Public Class Stopwatch

继承

Object

Stopwatch

示例

以下示例演示如何使用 Stopwatch 类来确定应用程序的执行时间。

using System;
using System.Diagnostics;
using System.Threading;
class Program
{
    static void Main(string[] args)
    {
        Stopwatch stopWatch = new Stopwatch();
        stopWatch.Start();
        Thread.Sleep(10000);
        stopWatch.Stop();
        // Get the elapsed time as a TimeSpan value.
        TimeSpan ts = stopWatch.Elapsed;

        // Format and display the TimeSpan value.
        string elapsedTime = String.Format("{0:00}:{1:00}:{2:00}.{3:00}",
            ts.Hours, ts.Minutes, ts.Seconds,
            ts.Milliseconds / 10);
        Console.WriteLine("RunTime " + elapsedTime);
    }
}

Imports System.Diagnostics
Imports System.Threading


Class Program

    Shared Sub Main(ByVal args() As String)
        Dim stopWatch As New Stopwatch()
        stopWatch.Start()
        Thread.Sleep(10000)
        stopWatch.Stop()
        ' Get the elapsed time as a TimeSpan value.
        Dim ts As TimeSpan = stopWatch.Elapsed

        ' Format and display the TimeSpan value.
        Dim elapsedTime As String = String.Format("{0:00}:{1:00}:{2:00}.{3:00}", ts.Hours, ts.Minutes, ts.Seconds, ts.Milliseconds / 10)
        Console.WriteLine( "RunTime " + elapsedTime)

    End Sub
End Class

下面的示例演示如何使用 Stopwatch 类来计算性能数据。

#using <System.dll>

using namespace System;
using namespace System::Diagnostics;

void DisplayTimerProperties()
{
   // Display the timer frequency and resolution.
   if ( Stopwatch::IsHighResolution )
   {
      Console::WriteLine( "Operations timed using the system's high-resolution performance counter." );
   }
   else
   {
      Console::WriteLine( "Operations timed using the DateTime class." );
   }

   Int64 frequency = Stopwatch::Frequency;
   Console::WriteLine( "  Timer frequency in ticks per second = {0}", frequency );
   Int64 nanosecPerTick = (1000L * 1000L * 1000L) / frequency;
   Console::WriteLine( "  Timer is accurate within {0} nanoseconds", nanosecPerTick );
}

void TimeOperations()
{
   Int64 nanosecPerTick = (1000L * 1000L * 1000L) / Stopwatch::Frequency;
   const long numIterations = 10000;
   
   // Define the operation title names.
   array<String^>^operationNames = {"Operation: Int32.Parse(\"0\")","Operation: Int32.TryParse(\"0\")","Operation: Int32.Parse(\"a\")","Operation: Int32.TryParse(\"a\")"};
   
   // Time four different implementations for parsing 
   // an integer from a string. 
   for ( int operation = 0; operation <= 3; operation++ )
   {
      // Define variables for operation statistics.
      Int64 numTicks = 0;
      Int64 numRollovers = 0;
      Int64 maxTicks = 0;
      Int64 minTicks = Int64::MaxValue;
      int indexFastest = -1;
      int indexSlowest = -1;
      Int64 milliSec = 0;
      Stopwatch ^ time10kOperations = Stopwatch::StartNew();
      
      // Run the current operation 10001 times.
      // The first execution time will be tossed
      // out, since it can skew the average time.
      for ( int i = 0; i <= numIterations; i++ )
      {
         Int64 ticksThisTime = 0;
         int inputNum;
         Stopwatch ^ timePerParse;
         switch ( operation )
         {
            case 0:
               
               // Parse a valid integer using
               // a try-catch statement.
               // Start a new stopwatch timer.
               timePerParse = Stopwatch::StartNew();
               try
               {
                  inputNum = Int32::Parse( "0" );
               }
               catch ( FormatException^ ) 
               {
                  inputNum = 0;
               }

               // Stop the timer, and save the
               // elapsed ticks for the operation.
               timePerParse->Stop();
               ticksThisTime = timePerParse->ElapsedTicks;
               break;

            case 1:
               
               // Parse a valid integer using
               // the TryParse statement.
               // Start a new stopwatch timer.
               timePerParse = Stopwatch::StartNew();
               if (  !Int32::TryParse( "0", inputNum ) )
               {
                  inputNum = 0;
               }
               
               // Stop the timer, and save the
               // elapsed ticks for the operation.
               timePerParse->Stop();
               ticksThisTime = timePerParse->ElapsedTicks;
               break;

            case 2:
               
               // Parse an invalid value using
               // a try-catch statement.
               // Start a new stopwatch timer.
               timePerParse = Stopwatch::StartNew();
               try
               {
                  inputNum = Int32::Parse( "a" );
               }
               catch ( FormatException^ ) 
               {
                  inputNum = 0;
               }

               // Stop the timer, and save the
               // elapsed ticks for the operation.
               timePerParse->Stop();
               ticksThisTime = timePerParse->ElapsedTicks;
               break;

            case 3:
               
               // Parse an invalid value using
               // the TryParse statement.
               // Start a new stopwatch timer.
               timePerParse = Stopwatch::StartNew();
               if (  !Int32::TryParse( "a", inputNum ) )
               {
                  inputNum = 0;
               }
               
               // Stop the timer, and save the
               // elapsed ticks for the operation.
               timePerParse->Stop();
               ticksThisTime = timePerParse->ElapsedTicks;
               break;

            default:
               break;
         }

         // Skip over the time for the first operation,
         // just in case it caused a one-time
         // performance hit.
         if ( i == 0 )
         {
            time10kOperations->Reset();
            time10kOperations->Start();
         }
         else
         {
            // Update operation statistics
            // for iterations 1-10001.
            if ( maxTicks < ticksThisTime )
            {
               indexSlowest = i;
               maxTicks = ticksThisTime;
            }
            if ( minTicks > ticksThisTime )
            {
               indexFastest = i;
               minTicks = ticksThisTime;
            }
            numTicks += ticksThisTime;
            if ( numTicks < ticksThisTime )
            {
               // Keep track of rollovers.
               numRollovers++;
            }
         }
      }
      
      // Display the statistics for 10000 iterations.
      time10kOperations->Stop();
      milliSec = time10kOperations->ElapsedMilliseconds;
      Console::WriteLine();
      Console::WriteLine( "{0} Summary:", operationNames[ operation ] );
      Console::WriteLine( "  Slowest time:  #{0}/{1} = {2} ticks", indexSlowest, numIterations, maxTicks );
      Console::WriteLine( "  Fastest time:  #{0}/{1} = {2} ticks", indexFastest, numIterations, minTicks );
      Console::WriteLine( "  Average time:  {0} ticks = {1} nanoseconds", numTicks / numIterations, (numTicks * nanosecPerTick) / numIterations );
      Console::WriteLine( "  Total time looping through {0} operations: {1} milliseconds", numIterations, milliSec );

   }
}

int main()
{
   DisplayTimerProperties();
   Console::WriteLine();
   Console::WriteLine( "Press the Enter key to begin:" );
   Console::ReadLine();
   Console::WriteLine();
   TimeOperations();
}

using System;
using System.Diagnostics;

namespace StopWatchSample
{
    class OperationsTimer
    {
        public static void Main()
        {
            DisplayTimerProperties();

            Console.WriteLine();
            Console.WriteLine("Press the Enter key to begin:");
            Console.ReadLine();
            Console.WriteLine();

            TimeOperations();
        }

        public static void DisplayTimerProperties()
        {
            // Display the timer frequency and resolution.
            if (Stopwatch.IsHighResolution)
            {
                Console.WriteLine("Operations timed using the system's high-resolution performance counter.");
            }
            else
            {
                Console.WriteLine("Operations timed using the DateTime class.");
            }

            long frequency = Stopwatch.Frequency;
            Console.WriteLine("  Timer frequency in ticks per second = {0}",
                frequency);
            long nanosecPerTick = (1000L*1000L*1000L) / frequency;
            Console.WriteLine("  Timer is accurate within {0} nanoseconds",
                nanosecPerTick);
        }

        private static void TimeOperations()
        {
            long nanosecPerTick = (1000L*1000L*1000L) / Stopwatch.Frequency;
            const long numIterations = 10000;

            // Define the operation title names.
            String [] operationNames = {"Operation: Int32.Parse(\"0\")",
                                           "Operation: Int32.TryParse(\"0\")",
                                           "Operation: Int32.Parse(\"a\")",
                                           "Operation: Int32.TryParse(\"a\")"};

            // Time four different implementations for parsing
            // an integer from a string.

            for (int operation = 0; operation <= 3; operation++)
            {
                // Define variables for operation statistics.
                long numTicks = 0;
                long numRollovers = 0;
                long maxTicks = 0;
                long minTicks = Int64.MaxValue;
                int indexFastest = -1;
                int indexSlowest = -1;
                long milliSec = 0;

                Stopwatch time10kOperations = Stopwatch.StartNew();

                // Run the current operation 10001 times.
                // The first execution time will be tossed
                // out, since it can skew the average time.

                for (int i=0; i<=numIterations; i++)
                {
                    long ticksThisTime = 0;
                    int inputNum;
                    Stopwatch timePerParse;

                    switch (operation)
                    {
                        case 0:
                            // Parse a valid integer using
                            // a try-catch statement.

                            // Start a new stopwatch timer.
                            timePerParse = Stopwatch.StartNew();

                            try
                            {
                                inputNum = Int32.Parse("0");
                            }
                            catch (FormatException)
                            {
                                inputNum = 0;
                            }

                            // Stop the timer, and save the
                            // elapsed ticks for the operation.

                            timePerParse.Stop();
                            ticksThisTime = timePerParse.ElapsedTicks;
                            break;
                        case 1:
                            // Parse a valid integer using
                            // the TryParse statement.

                            // Start a new stopwatch timer.
                            timePerParse = Stopwatch.StartNew();

                            if (!Int32.TryParse("0", out inputNum))
                            {
                                inputNum = 0;
                            }

                            // Stop the timer, and save the
                            // elapsed ticks for the operation.
                            timePerParse.Stop();
                            ticksThisTime = timePerParse.ElapsedTicks;
                            break;
                        case 2:
                            // Parse an invalid value using
                            // a try-catch statement.

                            // Start a new stopwatch timer.
                            timePerParse = Stopwatch.StartNew();

                            try
                            {
                                inputNum = Int32.Parse("a");
                            }
                            catch (FormatException)
                            {
                                inputNum = 0;
                            }

                            // Stop the timer, and save the
                            // elapsed ticks for the operation.
                            timePerParse.Stop();
                            ticksThisTime = timePerParse.ElapsedTicks;
                            break;
                        case 3:
                            // Parse an invalid value using
                            // the TryParse statement.

                            // Start a new stopwatch timer.
                            timePerParse = Stopwatch.StartNew();

                            if (!Int32.TryParse("a", out inputNum))
                            {
                                inputNum = 0;
                            }

                            // Stop the timer, and save the
                            // elapsed ticks for the operation.
                            timePerParse.Stop();
                            ticksThisTime = timePerParse.ElapsedTicks;
                            break;

                        default:
                            break;
                    }

                    // Skip over the time for the first operation,
                    // just in case it caused a one-time
                    // performance hit.
                    if (i == 0)
                    {
                        time10kOperations.Reset();
                        time10kOperations.Start();
                    }
                    else
                    {

                        // Update operation statistics
                        // for iterations 1-10000.
                        if (maxTicks < ticksThisTime)
                        {
                            indexSlowest = i;
                            maxTicks = ticksThisTime;
                        }
                        if (minTicks > ticksThisTime)
                        {
                            indexFastest = i;
                            minTicks = ticksThisTime;
                        }
                        numTicks += ticksThisTime;
                        if (numTicks < ticksThisTime)
                        {
                            // Keep track of rollovers.
                            numRollovers ++;
                        }
                    }
                }

                // Display the statistics for 10000 iterations.

                time10kOperations.Stop();
                milliSec = time10kOperations.ElapsedMilliseconds;

                Console.WriteLine();
                Console.WriteLine("{0} Summary:", operationNames[operation]);
                Console.WriteLine("  Slowest time:  #{0}/{1} = {2} ticks",
                    indexSlowest, numIterations, maxTicks);
                Console.WriteLine("  Fastest time:  #{0}/{1} = {2} ticks",
                    indexFastest, numIterations, minTicks);
                Console.WriteLine("  Average time:  {0} ticks = {1} nanoseconds",
                    numTicks / numIterations,
                    (numTicks * nanosecPerTick) / numIterations );
                Console.WriteLine("  Total time looping through {0} operations: {1} milliseconds",
                    numIterations, milliSec);
            }
        }
     }
}

Imports System.Diagnostics

Class OperationsTimer
   
   Public Shared Sub Main()
      DisplayTimerProperties()
      
      Console.WriteLine()
      Console.WriteLine("Press the Enter key to begin:")
      Console.ReadLine()
      Console.WriteLine()
      
      TimeOperations()
   End Sub
   
   
   Public Shared Sub DisplayTimerProperties()

      ' Display the timer frequency and resolution.
      If Stopwatch.IsHighResolution Then
         Console.WriteLine("Operations timed using the system's high-resolution performance counter.")
      Else
         Console.WriteLine("Operations timed using the DateTime class.")
      End If
      
      Dim frequency As Long = Stopwatch.Frequency
      Console.WriteLine("  Timer frequency in ticks per second = {0}", frequency)
      Dim nanosecPerTick As Long = 1000000000 / frequency
      Console.WriteLine("  Timer is accurate within {0} nanoseconds", nanosecPerTick)

   End Sub
   
   Private Shared Sub TimeOperations()

      Dim nanosecPerTick As Long = 1000000000 / Stopwatch.Frequency
      Const numIterations As Long = 10000
      
      ' Define the operation title names.
      Dim operationNames As String() =  _
        {"Operation: Int32.Parse(""0"")", _
         "Operation: Int32.TryParse(""0"")", _
         "Operation: Int32.Parse(""a"")", _
         "Operation: Int32.TryParse(""a"")"}
      
      ' Time four different implementations for parsing 
      ' an integer from a string. 

      Dim operation As Integer
      For operation = 0 To 3
         ' Define variables for operation statistics.
         Dim numTicks As Long = 0
         Dim numRollovers As Long = 0
         Dim maxTicks As Long = 0
         Dim minTicks As Long = Int64.MaxValue
         Dim indexFastest As Integer = - 1
         Dim indexSlowest As Integer = - 1
         Dim milliSec As Long = 0
         
         Dim time10kOperations As Stopwatch = Stopwatch.StartNew()
         
         ' Run the current operation 10001 times.
         ' The first execution time will be tossed
         ' out, since it can skew the average time.
         Dim i As Integer
         For i = 0 To numIterations
            Dim ticksThisTime As Long = 0
            Dim inputNum As Integer
            Dim timePerParse As Stopwatch
            
            Select Case operation
               Case 0
                  ' Parse a valid integer using
                  ' a try-catch statement.
                  ' Start a new stopwatch timer.
                  timePerParse = Stopwatch.StartNew()
                  
                  Try
                     inputNum = Int32.Parse("0")
                  Catch e As FormatException
                     inputNum = 0
                  End Try
                  
                  ' Stop the timer, and save the
                  ' elapsed ticks for the operation.
                  timePerParse.Stop()
                  ticksThisTime = timePerParse.ElapsedTicks
               Case 1
                  ' Parse a valid integer using
                  ' the TryParse statement.
                  ' Start a new stopwatch timer.
                  timePerParse = Stopwatch.StartNew()
                  
                  If Not Int32.TryParse("0", inputNum) Then
                     inputNum = 0
                  End If
                  
                  ' Stop the timer, and save the
                  ' elapsed ticks for the operation.
                  timePerParse.Stop()
                  ticksThisTime = timePerParse.ElapsedTicks
               Case 2
                  ' Parse an invalid value using
                  ' a try-catch statement.
                  ' Start a new stopwatch timer.
                  timePerParse = Stopwatch.StartNew()
                  
                  Try
                     inputNum = Int32.Parse("a")
                  Catch e As FormatException
                     inputNum = 0
                  End Try
                  
                  ' Stop the timer, and save the
                  ' elapsed ticks for the operation.
                  timePerParse.Stop()
                  ticksThisTime = timePerParse.ElapsedTicks
               Case 3
                  ' Parse an invalid value using
                  ' the TryParse statement.
                  ' Start a new stopwatch timer.
                  timePerParse = Stopwatch.StartNew()
                  
                  If Not Int32.TryParse("a", inputNum) Then
                     inputNum = 0
                  End If
                  
                  ' Stop the timer, and save the
                  ' elapsed ticks for the operation.
                  timePerParse.Stop()
                  ticksThisTime = timePerParse.ElapsedTicks
               
               Case Else
            End Select
            
            ' Skip over the time for the first operation,
            ' just in case it caused a one-time
            ' performance hit.
            If i = 0 Then
               time10kOperations.Reset()
               time10kOperations.Start()
            Else
               
               ' Update operation statistics
               ' for iterations 1-10001.
               If maxTicks < ticksThisTime Then
                  indexSlowest = i
                  maxTicks = ticksThisTime
               End If
               If minTicks > ticksThisTime Then
                  indexFastest = i
                  minTicks = ticksThisTime
               End If
               numTicks += ticksThisTime
               If numTicks < ticksThisTime Then
                  ' Keep track of rollovers.
                  numRollovers += 1
               End If
            End If
         Next i
         
         ' Display the statistics for 10000 iterations.
         time10kOperations.Stop()
         milliSec = time10kOperations.ElapsedMilliseconds
         
         Console.WriteLine()
         Console.WriteLine("{0} Summary:", operationNames(operation))
         Console.WriteLine("  Slowest time:  #{0}/{1} = {2} ticks", _
            indexSlowest, numIterations, maxTicks)
         Console.WriteLine("  Fastest time:  #{0}/{1} = {2} ticks", _
            indexFastest, numIterations, minTicks)
         Console.WriteLine("  Average time:  {0} ticks = {1} nanoseconds", _
            numTicks / numIterations, numTicks * nanosecPerTick / numIterations)
         Console.WriteLine("  Total time looping through {0} operations: {1} milliseconds", _
            numIterations, milliSec)
      Next operation

   End Sub
End Class

注解

实例 Stopwatch 可以测量一个间隔的已用时间，或跨多个间隔的总已用时间。 在典型Stopwatch方案中，调用 Start 方法，最终调用 Stop 方法，然后使用 属性检查运行时间Elapsed。

Stopwatch实例正在运行或已停止;使用 IsRunning 确定 的Stopwatch当前状态。 使用 Start 开始测量已用时间;使用 Stop 停止测量已用时间。 通过属性 Elapsed、 ElapsedMilliseconds或 ElapsedTicks查询已用时间值。 可以在实例正在运行或停止时查询已用时间属性。 运行时间属性在 Stopwatch 运行时稳步增加;当实例停止时，它们保持不变。

默认情况下，实例的已用时间值 Stopwatch 等于所有测量时间间隔的总和。 对 的每个调用 Start 在累积运行时间开始计数;对 的每次调用 Stop 将结束当前间隔度量并冻结累积已用时间值。 Reset使用 方法清除现有Stopwatch实例中的累积运行时间。

通过 Stopwatch 对基础计时器机制中的计时器计时周期进行计数来测量运行时间。 如果安装的硬件和操作系统支持高分辨率性能计数器，则 Stopwatch 类使用该计数器来测量运行时间。 否则， Stopwatch 类使用系统计时器来测量已用时间。 Frequency使用 和 IsHighResolution 字段确定计时实现的Stopwatch精度和分辨率。

类 Stopwatch 有助于在托管代码中操作与计时相关的性能计数器。 具体而言， Frequency 字段和 GetTimestamp 方法可用于代替非托管 Windows API QueryPerformanceFrequency 和 QueryPerformanceCounter。

构造函数

字段

属性

方法

适用于

另请参阅

• TimeSpan