Stopwatch.ElapsedMilliseconds 属性

定义

获取当前实例测量得出的总运行时间(以毫秒为单位)。Gets the total elapsed time measured by the current instance, in milliseconds.

public:
 property long ElapsedMilliseconds { long get(); };
public long ElapsedMilliseconds { get; }
member this.ElapsedMilliseconds : int64
Public ReadOnly Property ElapsedMilliseconds As Long

属性值

一个只读长整型,表示当前实例测量得出的总毫秒数。A read-only long integer representing the total number of milliseconds measured by the current instance.

示例

下面的示例使用Stopwatch类来测量四个不同实现的性能, 用于分析字符串中的整数。The following example uses the Stopwatch class to measure the performance of four different implementations for parsing an integer from a string. 此代码示例是为Stopwatch类提供的更大示例的一部分。This code example is part of a larger example provided for the Stopwatch class.

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 );

   }
}
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 1-10001.
                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);
    }
}
   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

此属性表示将运行时间向下舍入到最接近的整数毫秒值。This property represents elapsed time rounded down to the nearest whole millisecond value. 对于更高的精度度量, Elapsed使用ElapsedTicks或属性。For higher precision measurements, use the Elapsed or ElapsedTicks properties.

可以在Elapsed Stopwatch实例正在运行或ElapsedMilliseconds已停止ElapsedTicks时查询属性、和。You can query the properties Elapsed, ElapsedMilliseconds, and ElapsedTicks while the Stopwatch instance is running or stopped. 运行的Stopwatch时间属性在运行时将持续增加; 当实例停止时, 属性将保持不变。The elapsed time properties steadily increase while the Stopwatch is running; they remain constant when the instance is stopped.

默认情况下, Stopwatch实例的运行时间值等于所有测量的时间间隔的总计。By default, the elapsed time value of a Stopwatch instance equals the total of all measured time intervals. 每次调用Start都会在累计运行时间进行计数; 每次Stop调用都将结束当前间隔度量, 并冻结累计运行时间值。Each call to Start begins counting at the cumulative elapsed time; each call to Stop ends the current interval measurement and freezes the cumulative elapsed time value. 使用方法清除现有Stopwatch实例中的累计运行时间。 ResetUse the Reset method to clear the cumulative elapsed time in an existing Stopwatch instance.

适用于

另请参阅