Stopwatch.ElapsedMilliseconds 屬性

定義

命名空間:

System.Diagnostics

組件:

System.Runtime.dll

來源:

Stopwatch.cs

取得目前執行個體所測量的已耗用時間總和，以毫秒為單位。

C#

public long ElapsedMilliseconds { get; }

屬性值

Int64

表示目前執行個體所測量之毫秒總數的唯讀長整數 (Long Integer)。

範例

下列範例會 Stopwatch 使用 類別來測量四個不同實作的效能，以剖析字串中的整數。 此程式代碼範例是提供給 類別之較大範例的 Stopwatch 一部分。

C#

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);
    }
}

備註

這個屬性代表四捨五入到最接近整數毫秒值的經過時間。 如需較高的精確度測量，請使用 Elapsed 或 ElapsedTicks 屬性。

您可以在實體執行或停止時Stopwatch查詢屬性Elapsed、 ElapsedMilliseconds與 ElapsedTicks 。 執行 時 Stopwatch ，經過的時間屬性會穩定增加;當實例停止時，它們會維持不變。

根據預設，實例的經過時間值 Stopwatch 等於所有測量時間間隔的總計。 每個呼叫 Start 都會在累計經過的時間開始計算;每個呼叫 Stop 結束目前的間隔度量，並凍結累計耗用的時間值。 Reset使用方法來清除現有Stopwatch實例中累積經過的時間。

適用於

另請參閱

• Elapsed
• ElapsedTicks