c# - 继承 WeakReference 在 Silverlight 中抛出 ReflectionTypeLoadException

Question

我正在尝试在我的 Silverlight 应用程序中使用类型安全的 WeakReference。我正在按照本网站上的食谱进行操作:http://ondevelopment.blogspot.com/2008/01/generic-weak-reference.html仅使用 System.WeakReference 并省略引用序列化的内容。

当我尝试运行它时它抛出 ReflectionTypeLoadException，并显示以下消息:

"{System.TypeLoadException: Inheritance security rules violated whileoverriding member:'Coatue.Silverlight.Shared.Cache.WeakReference`1..ctor()'. Securityaccessibility of the overriding method must match the securityaccessibility of the method being overriden.}"

这是我使用的代码:

using System;

namespace Frank
{
    public class WeakReference<T>
        : WeakReference where T : class
    {
        public WeakReference(T target)
            : base(target) { }

        public WeakReference(T target, bool trackResurrection)
            : base(target, trackResurrection) { }

        protected WeakReference() : base() { }

        public new T Target
        {
            get
            {
                return (T)base.Target;
            }
            set
            {
                base.Target = value;
            }
        }
    }
}

Answer 1

正如 Thomas 所提到的，您不能从 silverlight 中的弱引用继承，但您可以包装它:

using System;

namespace Frank
{
    public class WeakReference<T> where T : class
    {
        private readonly WeakReference inner;

        public WeakReference(T target)
            : this(target, false)
        { }

        public WeakReference(T target, bool trackResurrection)
        {
            if(target == null) throw new ArgumentNullException("target");
            this.inner = new WeakReference(target, trackResurrection);
        }

        public T Target
        {
            get
            {
                return (T)this.inner.Target;
            }
            set
            {
                this.inner.Target = value;
            }
        }

        public bool IsAlive {
            get {
                 return this.inner.IsAlive;
            }
        }
    }
}