System.GC.GetGeneration 方法 (WeakReference)

System.GC.GetGeneration 方法 (WeakReference)例子

下面的示例演示如何使用 GetGeneration 方法来确定弱引用对象的存现时期。

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();
            }
        }
    }
}

相关资源

GC 类

GetGeneration 重载

System 命名空间

MaxGeneration

MSDN