Interlocked.Exchange 方法

定義

命名空間:

System.Threading

組件:

System.Threading.dll

把變數設定為特定值，成為不可部分完成的作業。

多載

Exchange(UInt32, UInt32)	將 32 位元不帶正負號的整數設定為指定值，然後傳回原始值，成為不可部分完成的作業。
Exchange(Single, Single)	將單精確度浮點數設定為指定值，然後傳回原始值，成為不可部分完成的作業。
Exchange(UIntPtr, UIntPtr)	將平台特定的控制代碼或指標設定為指定值，然後傳回原始值，成為不可部分完成的作業。
Exchange(UInt64, UInt64)	將 64 位元不帶正負號的整數設定為指定值，然後傳回原始值，成為不可部分完成的作業。
Exchange(IntPtr, IntPtr)	將平台特定的控制代碼或指標設定為指定值，然後傳回原始值，成為不可部分完成的作業。
Exchange(Int64, Int64)	將 64 位元帶正負號的整數設定為指定值，然後傳回原始值，成為不可部分完成的作業。
Exchange(Int32, Int32)	將 32 位元帶正負號的整數設定為指定值，然後傳回原始值，成為不可部分完成的作業。
Exchange(Double, Double)	將雙精確度浮點數設定為指定值，然後傳回原始值，成為不可部分完成的作業。
Exchange(Object, Object)	將物件設定為指定值，然後傳回原始物件的參考，成為不可部分完成的作業。
Exchange<T>(T, T)	將指定類型 T 的變數設定為指定值，然後傳回原始值，成為不可部分完成的作業。

Exchange(UInt32, UInt32)

Source:

Interlocked.cs

重要

此 API 不符合 CLS 規範。

將 32 位元不帶正負號的整數設定為指定值，然後傳回原始值，成為不可部分完成的作業。

public:
 static System::UInt32 Exchange(System::UInt32 % location1, System::UInt32 value);

[System.CLSCompliant(false)]
public static uint Exchange (ref uint location1, uint value);

[<System.CLSCompliant(false)>]
static member Exchange : uint32 * uint32 -> uint32

Public Shared Function Exchange (ByRef location1 As UInteger, value As UInteger) As UInteger

參數

location1

UInt32

要設定為特定值的變數。

value

UInt32

location1 參數要設定的值。

傳回

UInt32

location1 的原始值。

屬性

CLSCompliantAttribute

例外狀況

NullReferenceException

location1 的位址為 null 指標。

Exchange(Single, Single)

Source:

Interlocked.cs

將單精確度浮點數設定為指定值，然後傳回原始值，成為不可部分完成的作業。

public:
 static float Exchange(float % location1, float value);

public static float Exchange (ref float location1, float value);

static member Exchange : single * single -> single

Public Shared Function Exchange (ByRef location1 As Single, value As Single) As Single

參數

location1

Single

要設定為特定值的變數。

value

Single

location1 參數要設定的值。

傳回

Single

location1 的原始值。

例外狀況

NullReferenceException

location1 的位址為 null 指標。

另請參閱

• Managed 執行緒處理
• 同步處理原始物件概觀

Exchange(UIntPtr, UIntPtr)

Source:

Interlocked.cs

重要

此 API 不符合 CLS 規範。

將平台特定的控制代碼或指標設定為指定值，然後傳回原始值，成為不可部分完成的作業。

public:
 static UIntPtr Exchange(UIntPtr % location1, UIntPtr value);

[System.CLSCompliant(false)]
public static UIntPtr Exchange (ref UIntPtr location1, UIntPtr value);

[<System.CLSCompliant(false)>]
static member Exchange : unativeint * unativeint -> unativeint

Public Shared Function Exchange (ByRef location1 As UIntPtr, value As UIntPtr) As UIntPtr

參數

location1

UIntPtr

unativeint

要設定為特定值的變數。

value

UIntPtr

unativeint

location1 參數要設定的值。

傳回

UIntPtr

unativeint

location1 的原始值。

屬性

CLSCompliantAttribute

例外狀況

NullReferenceException

location1 的位址為 null 指標。

Exchange(UInt64, UInt64)

Source:

Interlocked.cs

重要

此 API 不符合 CLS 規範。

將 64 位元不帶正負號的整數設定為指定值，然後傳回原始值，成為不可部分完成的作業。

public:
 static System::UInt64 Exchange(System::UInt64 % location1, System::UInt64 value);

[System.CLSCompliant(false)]
public static ulong Exchange (ref ulong location1, ulong value);

[<System.CLSCompliant(false)>]
static member Exchange : uint64 * uint64 -> uint64

Public Shared Function Exchange (ByRef location1 As ULong, value As ULong) As ULong

參數

location1

UInt64

要設定為特定值的變數。

value

UInt64

location1 參數要設定的值。

傳回

UInt64

location1 的原始值。

屬性

CLSCompliantAttribute

例外狀況

NullReferenceException

location1 的位址為 null 指標。

Exchange(IntPtr, IntPtr)

Source:

Interlocked.cs

將平台特定的控制代碼或指標設定為指定值，然後傳回原始值，成為不可部分完成的作業。

public:
 static IntPtr Exchange(IntPtr % location1, IntPtr value);

public static IntPtr Exchange (ref IntPtr location1, IntPtr value);

static member Exchange : nativeint * nativeint -> nativeint

Public Shared Function Exchange (ByRef location1 As IntPtr, value As IntPtr) As IntPtr

參數

location1

IntPtr

nativeint

要設定為特定值的變數。

value

IntPtr

nativeint

location1 參數要設定的值。

傳回

IntPtr

nativeint

location1 的原始值。

例外狀況

NullReferenceException

location1 的位址為 null 指標。

另請參閱

• Managed 執行緒處理
• 同步處理原始物件概觀

Exchange(Int64, Int64)

Source:

Interlocked.cs

將 64 位元帶正負號的整數設定為指定值，然後傳回原始值，成為不可部分完成的作業。

public:
 static long Exchange(long % location1, long value);

public static long Exchange (ref long location1, long value);

static member Exchange : int64 * int64 -> int64

Public Shared Function Exchange (ByRef location1 As Long, value As Long) As Long

參數

location1

Int64

要設定為特定值的變數。

value

Int64

location1 參數要設定的值。

傳回

Int64

location1 的原始值。

例外狀況

NullReferenceException

location1 的位址為 null 指標。

另請參閱

• Managed 執行緒處理
• 同步處理原始物件概觀

Exchange(Int32, Int32)

Source:

Interlocked.cs

將 32 位元帶正負號的整數設定為指定值，然後傳回原始值，成為不可部分完成的作業。

public:
 static int Exchange(int % location1, int value);

public static int Exchange (ref int location1, int value);

static member Exchange : int * int -> int

Public Shared Function Exchange (ByRef location1 As Integer, value As Integer) As Integer

參數

location1

Int32

要設定為特定值的變數。

value

Int32

location1 參數要設定的值。

傳回

Int32

location1 的原始值。

例外狀況

ArgumentNullException

location1 的位址為 null 指標。

NullReferenceException

location1 的位址為 null 指標。

範例

下列程式代碼範例顯示安全線程的資源鎖定機制。

using namespace System;
using namespace System::Threading;

const int numThreads = 10;
const int numThreadIterations = 5;
ref class MyInterlockedExchangeExampleClass
{
public:
   static void MyThreadProc()
   {
      for ( int i = 0; i < numThreadIterations; i++ )
      {
         UseResource();
         
         //Wait 1 second before next attempt.
         Thread::Sleep( 1000 );

      }
   }


private:
   //A simple method that denies reentrancy.
   static bool UseResource()
   {
      
      //0 indicates that the method is not in use.
      if ( 0 == Interlocked::Exchange( usingResource, 1 ) )
      {
         Console::WriteLine( " {0} acquired the lock", Thread::CurrentThread->Name );
         
         //Code to access a resource that is not thread safe would go here.
         //Simulate some work
         Thread::Sleep( 500 );
         Console::WriteLine( " {0} exiting lock", Thread::CurrentThread->Name );
         
         //Release the lock
         Interlocked::Exchange( usingResource, 0 );
         return true;
      }
      else
      {
         Console::WriteLine( " {0} was denied the lock", Thread::CurrentThread->Name );
         return false;
      }
   }


   //0 for false, 1 for true.
   static int usingResource;
};

int main()
{
   Thread^ myThread;
   Random^ rnd = gcnew Random;
   for ( int i = 0; i < numThreads; i++ )
   {
      myThread = gcnew Thread( gcnew ThreadStart( MyInterlockedExchangeExampleClass::MyThreadProc ) );
      myThread->Name = String::Format( "Thread {0}", i + 1 );
      
      //Wait a random amount of time before starting next thread.
      Thread::Sleep( rnd->Next( 0, 1000 ) );
      myThread->Start();

   }
}

using System;
using System.Threading;

namespace InterlockedExchange_Example
{
    class MyInterlockedExchangeExampleClass
    {
        //0 for false, 1 for true.
        private static int usingResource = 0;

        private const int numThreadIterations = 5;
        private const int numThreads = 10;

        static void Main()
        {
            Thread myThread;
            Random rnd = new Random();

            for(int i = 0; i < numThreads; i++)
            {
                myThread = new Thread(new ThreadStart(MyThreadProc));
                myThread.Name = String.Format("Thread{0}", i + 1);
            
                //Wait a random amount of time before starting next thread.
                Thread.Sleep(rnd.Next(0, 1000));
                myThread.Start();
            }
        }

        private static void MyThreadProc()
        {
            for(int i = 0; i < numThreadIterations; i++)
            {
                UseResource();
            
                //Wait 1 second before next attempt.
                Thread.Sleep(1000);
            }
        }

        //A simple method that denies reentrancy.
        static bool UseResource()
        {
            //0 indicates that the method is not in use.
            if(0 == Interlocked.Exchange(ref usingResource, 1))
            {
                Console.WriteLine("{0} acquired the lock", Thread.CurrentThread.Name);
            
                //Code to access a resource that is not thread safe would go here.
            
                //Simulate some work
                Thread.Sleep(500);

                Console.WriteLine("{0} exiting lock", Thread.CurrentThread.Name);
            
                //Release the lock
                Interlocked.Exchange(ref usingResource, 0);
                return true;
            }
            else
            {
                Console.WriteLine("   {0} was denied the lock", Thread.CurrentThread.Name);
                return false;
            }
        }
    }
}

Imports System.Threading

Namespace InterlockedExchange_Example
    Class MyInterlockedExchangeExampleClass
        '0 for false, 1 for true.
        Private Shared usingResource As Integer = 0

        Private Const numThreadIterations As Integer = 5
        Private Const numThreads As Integer = 10

        <MTAThread> _
        Shared Sub Main()
            Dim myThread As Thread
            Dim rnd As New Random()

            Dim i As Integer
            For i = 0 To numThreads - 1
                myThread = New Thread(AddressOf MyThreadProc)
                myThread.Name = String.Format("Thread{0}", i + 1)

                'Wait a random amount of time before starting next thread.
                Thread.Sleep(rnd.Next(0, 1000))
                myThread.Start()
            Next i
        End Sub

        Private Shared Sub MyThreadProc()
            Dim i As Integer
            For i = 0 To numThreadIterations - 1
                UseResource()

                'Wait 1 second before next attempt.
                Thread.Sleep(1000)
            Next i
        End Sub 

        'A simple method that denies reentrancy.
        Shared Function UseResource() As Boolean
            '0 indicates that the method is not in use.
            If 0 = Interlocked.Exchange(usingResource, 1) Then
                Console.WriteLine("{0} acquired the lock", Thread.CurrentThread.Name)

                'Code to access a resource that is not thread safe would go here.
                'Simulate some work
                Thread.Sleep(500)

                Console.WriteLine("{0} exiting lock", Thread.CurrentThread.Name)

                'Release the lock
                Interlocked.Exchange(usingResource, 0)
                Return True
            Else
                Console.WriteLine("   {0} was denied the lock", Thread.CurrentThread.Name)
                Return False
            End If
        End Function 
    End Class 
End Namespace

另請參閱

• Managed 執行緒處理
• 同步處理原始物件概觀

Exchange(Double, Double)

Source:

Interlocked.cs

將雙精確度浮點數設定為指定值，然後傳回原始值，成為不可部分完成的作業。

public:
 static double Exchange(double % location1, double value);

public static double Exchange (ref double location1, double value);

static member Exchange : double * double -> double

Public Shared Function Exchange (ByRef location1 As Double, value As Double) As Double

參數

location1

Double

要設定為特定值的變數。

value

Double

location1 參數要設定的值。

傳回

Double

location1 的原始值。

例外狀況

NullReferenceException

location1 的位址為 null 指標。

另請參閱

• Managed 執行緒處理
• 同步處理原始物件概觀

Exchange(Object, Object)

Source:

Interlocked.cs

將物件設定為指定值，然後傳回原始物件的參考，成為不可部分完成的作業。

public:
 static System::Object ^ Exchange(System::Object ^ % location1, System::Object ^ value);

public static object? Exchange (ref object? location1, object? value);

static member Exchange : obj * obj -> obj

Public Shared Function Exchange (ByRef location1 As Object, value As Object) As Object

參數

location1

Object

要設定為特定值的變數。

value

Object

location1 參數要設定的值。

傳回

Object

location1 的原始值。

例外狀況

ArgumentNullException

location1 的位址為 null 指標。

NullReferenceException

location1 的位址為 null 指標。

備註

重要

從 .NET Framework 2.0 開始，Exchange<T>(T, T) 方法多載會為參考型別提供型別安全的替代方法。 建議您呼叫它，而不是這個多載。

另請參閱

• Managed 執行緒處理
• 同步處理原始物件概觀

Exchange<T>(T, T)

Source:

Interlocked.CoreCLR.cs

將指定類型 T 的變數設定為指定值，然後傳回原始值，成為不可部分完成的作業。

public:
generic <typename T>
 where T : class static T Exchange(T % location1, T value);

public static T Exchange<T> (ref T location1, T value) where T : class;

static member Exchange : 'T * 'T -> 'T (requires 'T : null)

Public Shared Function Exchange(Of T As Class) (ByRef location1 As T, value As T) As T

類型參數

T

要用於 location1 和 value 的類型。 此類型必須是參考類型。

參數

location1

T

要設定為特定值的變數。 此為參考參數 (在 C# 中為 ref，在 Visual Basic 中為 ByRef)。

value

T

location1 參數要設定的值。

傳回

T

location1 的原始值。

例外狀況

NullReferenceException

location1 的位址為 null 指標。

備註

這個方法只支持參考型別。 、、、 和 Double 實值型別的方法Int32有多載Exchange，但不支援其他實值型Single別。 IntPtrInt64

注意

此方法多載最好是 Exchange(Object, Object) 方法多載，因為後者需要對目的地物件進行晚期綁定存取。