Stopwatch.StartNew 方法

定义

命名空间:

System.Diagnostics

程序集:

System.Runtime.dll

Source:

Stopwatch.cs

初始化新的 Stopwatch 实例，将运行时间属性设置为零，然后开始测量运行时间。

public:
 static System::Diagnostics::Stopwatch ^ StartNew();

public static System.Diagnostics.Stopwatch StartNew ();

static member StartNew : unit -> System.Diagnostics.Stopwatch

Public Shared Function StartNew () As Stopwatch

返回

Stopwatch

刚刚开始测量运行时间的 Stopwatch。

示例

下面的示例使用 Stopwatch 类来测量四个不同实现的性能，以便分析字符串中的整数。 此代码示例是为 Stopwatch 类提供的一个更大示例的一部分。

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;
}

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;
}

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

注解

此方法等效于调用构造函数， Stopwatch 然后在新实例上调用 Start 。

另请参阅

• Start()
• Stop()
• IsRunning
• Reset()