GC.GetGeneration 方法

定義

命名空間:: System

組件:: mscorlib.dll, System.Runtime.dll

組件:: netstandard.dll, System.Runtime.dll

組件:: System.Runtime.dll

組件:: mscorlib.dll

組件:: netstandard.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

回傳物件當前的世代編號。

多載

名稱	Description
GetGeneration(Object)	回傳指定物件的當前世代數。
GetGeneration(WeakReference)	回傳指定弱參考目標的當前世代數。

GetGeneration(Object)

來源:: GC.CoreCLR.cs

來源:: GC.CoreCLR.cs

來源:: GC.cs

來源:: GC.cs

來源:: GC.cs

回傳指定物件的當前世代數。

public:
 static int GetGeneration(System::Object ^ obj);

public static int GetGeneration(object obj);

static member GetGeneration : obj -> int

Public Shared Function GetGeneration (obj As Object) As Integer

參數

obj: Object

就是產生資訊所取得的對象。

傳回

Int32

目前的世代編號 obj，或 Int32.MaxValue。

範例

以下範例示範如何使用此 GetGeneration 方法來判定物體的年齡。接著範例執行垃圾回收以清理記憶體，並比較主控台中收集前後的記憶體總數。

using System;

namespace GCCollectIntExample
{
    class MyGCCollectClass
    {
        private const long maxGarbage = 1000;

        static void Main()
        {
            MyGCCollectClass myGCCol = new MyGCCollectClass();

            // Determine the maximum number of generations the system
        // garbage collector currently supports.
            Console.WriteLine("The highest generation is {0}", GC.MaxGeneration);

            myGCCol.MakeSomeGarbage();

            // Determine which generation myGCCol object is stored in.
            Console.WriteLine("Generation: {0}", GC.GetGeneration(myGCCol));

            // Determine the best available approximation of the number
        // of bytes currently allocated in managed memory.
            Console.WriteLine("Total Memory: {0}", GC.GetTotalMemory(false));

            // Perform a collection of generation 0 only.
            GC.Collect(0);

            // Determine which generation myGCCol object is stored in.
            Console.WriteLine("Generation: {0}", GC.GetGeneration(myGCCol));

            Console.WriteLine("Total Memory: {0}", GC.GetTotalMemory(false));

            // Perform a collection of all generations up to and including 2.
            GC.Collect(2);

            // Determine which generation myGCCol object is stored in.
            Console.WriteLine("Generation: {0}", GC.GetGeneration(myGCCol));
            Console.WriteLine("Total Memory: {0}", GC.GetTotalMemory(false));
            Console.Read();
        }

        void MakeSomeGarbage()
        {
            Version vt;

            for(int i = 0; i < maxGarbage; i++)
            {
                // Create objects and release them to fill up memory
        // with unused objects.
                vt = new Version();
            }
        }
    }
}

open System

let maxGarbage = 1000

type MyGCCollectClass() =
    member _.MakeSomeGarbage() =
        for _ = 1 to maxGarbage do
            // Create objects and release them to fill up memory with unused objects.
            Version() |> ignore

[<EntryPoint>]
let main _ =
    let myGCCol = MyGCCollectClass()

    // Determine the maximum number of generations the system
    // garbage collector currently supports.
    printfn $"The highest generation is {GC.MaxGeneration}"

    myGCCol.MakeSomeGarbage()

    // Determine which generation myGCCol object is stored in.
    printfn $"Generation: {GC.GetGeneration myGCCol}"

    // Determine the best available approximation of the number
    // of bytes currently allocated in managed memory.
    printfn $"Total Memory: {GC.GetTotalMemory false}"

    // Perform a collection of generation 0 only.
    GC.Collect 0

    // Determine which generation myGCCol object is stored in.
    printfn $"Generation: {GC.GetGeneration myGCCol}"

    printfn $"Total Memory: {GC.GetTotalMemory false}"

    // Perform a collection of all generations up to and including 2.
    GC.Collect 2

    // Determine which generation myGCCol object is stored in.
    printfn $"Generation: {GC.GetGeneration myGCCol}"
    printfn $"Total Memory: {GC.GetTotalMemory false}"

    0

Namespace GCCollectInt_Example
    Class MyGCCollectClass
        Private maxGarbage As Long = 10000

        Public Shared Sub Main()
            Dim myGCCol As New MyGCCollectClass

            'Determine the maximum number of generations the system
            'garbage collector currently supports.
            Console.WriteLine("The highest generation is {0}", GC.MaxGeneration)

            myGCCol.MakeSomeGarbage()

            'Determine which generation myGCCol object is stored in.
            Console.WriteLine("Generation: {0}", GC.GetGeneration(myGCCol))

            'Determine the best available approximation of the number 
            'of bytes currently allocated in managed memory.
            Console.WriteLine("Total Memory: {0}", GC.GetTotalMemory(False))

            'Perform a collection of generation 0 only.
            GC.Collect(0)

            'Determine which generation myGCCol object is stored in.
            Console.WriteLine("Generation: {0}", GC.GetGeneration(myGCCol))

            Console.WriteLine("Total Memory: {0}", GC.GetTotalMemory(False))

            'Perform a collection of all generations up to and including 2.
            GC.Collect(2)

            'Determine which generation myGCCol object is stored in.
            Console.WriteLine("Generation: {0}", GC.GetGeneration(myGCCol))
            Console.WriteLine("Total Memory: {0}", GC.GetTotalMemory(False))
            Console.Read()

        End Sub


        Sub MakeSomeGarbage()
            Dim vt As Version

            Dim i As Integer
            For i = 0 To maxGarbage - 1
                'Create objects and release them to fill up memory
                'with unused objects.
                vt = New Version
            Next i
        End Sub
    End Class
End Namespace

備註

使用此方法判斷物件的年齡，然後利用該資訊 Collect 強制垃圾回收器收集同一世代的物件。例如，當你有一組物件作為群組建立，但同時變得無法存取時，可以使用這個方法。

從 .NET 8 開始，此方法可能會回傳配置在非 GC 堆積上的物件 MaxValue。欲了解更多資訊，請參閱 GC。GetGeneration 可能會回傳 Int32.MaxValue。

另請參閱

MaxGeneration

適用於

GetGeneration(WeakReference)

來源:: GC.CoreCLR.cs

來源:: GC.CoreCLR.cs

來源:: GC.CoreCLR.cs

來源:: GC.CoreCLR.cs

來源:: GC.CoreCLR.cs

回傳指定弱參考目標的當前世代數。

public:
 static int GetGeneration(WeakReference ^ wo);

public static int GetGeneration(WeakReference wo);

static member GetGeneration : WeakReference -> int

Public Shared Function GetGeneration (wo As WeakReference) As Integer

參數

wo: WeakReference

A WeakReference 指的是要確定其生成次數的目標物件。

傳回

Int32

目標的當前世代數 wo為，或 MaxValue。

例外狀況

ArgumentException

垃圾回收已經在 wo.

ArgumentNullException

弱參考的目標已經被垃圾回收了。

範例

以下範例展示了使用此 GetGeneration 方法來判定弱參考物體年齡的方法。

using System;

namespace GCGetGenerationWeakExample
{
    public class MyGCCollectClass
    {
        private const long maxGarbage = 1000;

        static void Main()
        {
            // Create a strong reference to an object.
            MyGCCollectClass myGCCol = new MyGCCollectClass();

            // Put some objects in memory.
            myGCCol.MakeSomeGarbage();

            // Get the generation of managed memory where myGCCol is stored.
            Console.WriteLine("The object is in generation: {0}", GC.GetGeneration(myGCCol));
                        
            // Perform a full garbage collection.
            // Because there is a strong reference to myGCCol, it will
            // not be garbage collected.
            GC.Collect();
            
            // Get the generation of managed memory where myGCCol is stored.
            Console.WriteLine("The object is in generation: {0}", GC.GetGeneration(myGCCol));
            
            // Create a WeakReference to myGCCol.
            WeakReference wkref = new WeakReference(myGCCol);
            // Remove the strong reference to myGCCol.
            myGCCol = null;

            // Get the generation of managed memory where wkref is stored.
            Console.WriteLine("The WeakReference to the object is in generation: {0}", GC.GetGeneration(wkref));
            
            // Perform another full garbage collection.
            // A WeakReference will not survive a garbage collection.
            GC.Collect();
        
            // Try to get the generation of managed memory where wkref is stored.
            // Because it has been collected, an exception will be thrown.
            try
            {
                Console.WriteLine("The WeakReference to the object is in generation: {0}", GC.GetGeneration(wkref));
                Console.Read();
            }
            catch(Exception e)
            {
                Console.WriteLine("The WeakReference to the object has been garbage collected: '{0}'", e);
                Console.Read();
            }
        }

        void MakeSomeGarbage()
        {
            Version vt;

            for(int i = 0; i < maxGarbage; i++)
            {
                // Create objects and release them to fill up memory
                // with unused objects.
                vt = new Version();
            }
        }
    }
}

open System

let maxGarbage = 1000

[<AllowNullLiteral>]
type MyGCCollectClass() =
    member _.MakeSomeGarbage() =
        for i = 1 to maxGarbage do
            // Create objects and release them to fill up memory
            // with unused objects.
            Version() |> ignore

// Create a strong reference to an object.
let mutable myGCCol = MyGCCollectClass()

// Put some objects in memory.
myGCCol.MakeSomeGarbage()

// Get the generation of managed memory where myGCCol is stored.
printfn $"The object is in generation: {GC.GetGeneration myGCCol}"
            
// Perform a full garbage collection.
// Because there is a strong reference to myGCCol, it will
// not be garbage collected.
GC.Collect()

// Get the generation of managed memory where myGCCol is stored.
printfn $"The object is in generation: {GC.GetGeneration myGCCol}"

// Create a WeakReference to myGCCol.
let wkref = WeakReference myGCCol
// Remove the strong reference to myGCCol.
myGCCol <- null

// Get the generation of managed memory where wkref is stored.
printfn $"The WeakReference to the object is in generation: {GC.GetGeneration wkref}"

// Perform another full garbage collection.
// A WeakReference will not survive a garbage collection.
GC.Collect()

// Try to get the generation of managed memory where wkref is stored.
// Because it has been collected, an exception will be thrown.
try
    printfn $"The WeakReference to the object is in generation: {GC.GetGeneration wkref}"
    stdin.Read() |> ignore
with e ->
    printfn $"The WeakReference to the object has been garbage collected: '{e}'"
    stdin.Read() |> ignore

Namespace GCGetGenerationWeakExample

   Class MyGCCollectClass
      Private maxGarbage As Long = 1000

      Public Shared Sub Main()
         ' Create a strong reference to an object.
         Dim myGCCol As New MyGCCollectClass

         ' Put some objects in memory.
         myGCCol.MakeSomeGarbage()

         ' Get the generation of managed memory where myGCCol is stored.
         Console.WriteLine("The object is in generation: {0}", _
                            GC.GetGeneration(myGCCol))

         ' Perform a full garbage collection.
         ' Because there is a strong reference to myGCCol, it will
         ' not be garbage collected.
         GC.Collect()

         ' Get the generation of managed memory where myGCCol is stored.
         Console.WriteLine("The object is in generation: {0}", _
                            GC.GetGeneration(myGCCol))

         ' Create a WeakReference to myGCCol.
         Dim wkref As New WeakReference(myGCCol)
         ' Remove the strong reference to myGCCol.
         myGCCol = Nothing

         ' Get the generation of managed memory where wkref is stored.
         Console.WriteLine("The WeakReference to the object is in generation: {0}", _
                           GC.GetGeneration(wkref))

         ' Perform another full garbage collection.
         ' A WeakReference will not survive a garbage collection.
         GC.Collect()

         ' Try to get the generation of managed memory where wkref is stored.
         ' Because it has been collected, an exception will be thrown.
         Try
            Console.WriteLine("The WeakReference to the object is in generation: {0}", _
                               GC.GetGeneration(wkref))
            Console.Read()
         Catch e As Exception
            Console.WriteLine("The WeakReference to the object " & _
                              "has been garbage collected: '{0}'", e)
            Console.Read()
         End Try
      End Sub


      Sub MakeSomeGarbage()
         Dim vt As Version

         Dim i As Integer
         For i = 0 To maxGarbage - 1
            ' Create objects and release them to fill up memory
            ' with unused objects.
            vt = New Version
         Next i
      End Sub
   End Class
End Namespace

備註

從 .NET 8 開始，此方法可能會回傳配置在非 GC 堆積上的物件 MaxValue。欲了解更多資訊，請參閱 GC。GetGeneration 可能會回傳 Int32.MaxValue。

另請參閱

MaxGeneration

適用於

意見反應

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