C# WeakFunc类代码示例

 /// <summary>
 /// Initializes a new instance of the RelayCommand class.
 /// </summary>
 /// <param name="execute">The execution logic.</param>
 /// <param name="canExecute">The execution status logic.</param>
 /// <exception cref="T:System.ArgumentNullException">If the execute argument is null.</exception>
 public RelayCommand(Action execute, Func<bool> canExecute)
 {
     if (execute == null)
     {
         throw new ArgumentNullException("execute");
     }
     this._execute = new WeakAction(execute);
     if (canExecute != null)
     {
         this._canExecute = new WeakFunc<bool>(canExecute);
     }
 }

        /// <summary>
        /// Initializes a new instance of the RelayCommand class.
        /// </summary>
        /// <param name="execute">The execution logic.</param>
        /// <param name="canExecute">The execution status logic.</param>
        /// <exception cref="ArgumentNullException">If the execute argument is null.</exception>
        public RelayCommand(Action execute, Func<bool> canExecute)
        {
            Idle = true;

            if (execute == null)
            {
                throw new ArgumentNullException("execute");
            }

            ExecuteAction = new WeakAction(execute);

            if (canExecute != null)
            {
                _canExecute = new WeakFunc<bool>(canExecute);
            }
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="ActionCommand"/> class.
        /// </summary>
        /// <param name="target">The target.</param>
        /// <param name="methodName">Name of the method.</param>
        public ActionCommand(object target, string methodName) {
            if (target == null)
                throw new ArgumentNullException("target");

            targetReference = new WeakReference(target);
            method = target.GetType().GetMethod(methodName);
            if (method == null)
                throw new ArgumentException(@"Specified method cannot be found.", "methodName");

            guardName = "Can" + method.Name;
            var guard = target.GetType().GetMethod("get_" + guardName);
            var inpc = target as INotifyPropertyChanged;
            if (inpc == null || guard == null) return;

            WeakEventHandler.Register<PropertyChangedEventArgs>(inpc, "PropertyChanged", OnPropertyChanged);
            canExecute = new WeakFunc<bool>(inpc, guard);
        }

        public PublicTestClassWithResult(WeakActionTestCase testCase)
        {
            switch (testCase)
            {
                case WeakActionTestCase.PublicNamedMethod:
                    Func = new WeakFunc<string>(
                        this,
                        DoStuffPublically);
                    break;
                case WeakActionTestCase.PrivateNamedMethod:
                    Func = new WeakFunc<string>(
                        this,
                        DoStuffPrivately);
                    break;
                case WeakActionTestCase.PublicStaticMethod:
                    Func = new WeakFunc<string>(
                        this,
                        DoStuffPublicallyAndStatically);
                    break;
                case WeakActionTestCase.PrivateStaticMethod:
                    Func = new WeakFunc<string>(
                        this,
                        DoStuffPrivatelyAndStatically);
                    break;
                case WeakActionTestCase.AnonymousStaticMethod:
                    Func = new WeakFunc<string>(
                        this,
                        () =>
                        {
                            Result = Expected;
                            return Result;
                        });
                    break;
                case WeakActionTestCase.AnonymousMethod:
                    Func = new WeakFunc<string>(
                        this,
                        () =>
                        {
                            Result = Expected + _index;
                            return Result;
                        });
                    break;
            }

        }

        public void TestStaticMethodWithNonNullTarget()
        {
            Reset();

            _common = new CommonTestClass();
            _reference = new WeakReference(_common);
            Assert.IsTrue(_reference.IsAlive);

            var func = new WeakFunc<string>(_common, DoStuffStaticWithResult);
            Assert.IsTrue(func.IsAlive);

            _common = null;
            GC.Collect();

            Assert.IsFalse(_reference.IsAlive);
            Assert.IsFalse(func.IsAlive);
        }

 public void TestStaticMethodWithNullTarget()
 {
     Reset();
     var func = new WeakFunc<string>(null, DoStuffStaticWithResult);
     Assert.IsTrue(func.IsAlive);
 }

            public WeakFunc<string> GetFunc(WeakActionTestCase testCase)
            {
                WeakFunc<string> action = null;

                switch (testCase)
                {
                    case WeakActionTestCase.PublicNamedMethod:
                        action = new WeakFunc<string>(
                            this,
                            DoStuffPublicallyWithResult);
                        break;
                    case WeakActionTestCase.InternalNamedMethod:
                        action = new WeakFunc<string>(
                            this,
                            DoStuffInternallyWithResult);
                        break;
                    case WeakActionTestCase.PrivateNamedMethod:
                        action = new WeakFunc<string>(
                            this,
                            DoStuffPrivatelyWithResult);
                        break;
                    case WeakActionTestCase.PublicStaticMethod:
                        action = new WeakFunc<string>(
                            this,
                            DoStuffPublicallyAndStaticallyWithResult);
                        break;
                    case WeakActionTestCase.InternalStaticMethod:
                        action = new WeakFunc<string>(
                            this,
                            DoStuffInternallyAndStaticallyWithResult);
                        break;
                    case WeakActionTestCase.PrivateStaticMethod:
                        action = new WeakFunc<string>(
                            this,
                            DoStuffPrivatelyAndStaticallyWithResult);
                        break;
                    case WeakActionTestCase.AnonymousStaticMethod:
                        action = new WeakFunc<string>(
                            this,
                            () =>
                                {
                                    Result = Expected;
                                    return Result;
                                });
                        break;
                    case WeakActionTestCase.AnonymousMethod:
                        action = new WeakFunc<string>(
                            this,
                            () =>
                                {
                                    Result = Expected + _index;
                                    return Result;
                                });
                        break;
                }

                return action;
            }

 public void TestNonStaticMethodWithNullTarget()
 {
     Reset();
     WeakFunc<string> func = new WeakFunc<string>(null, DoStuffWithResult);
     Assert.IsFalse(func.IsAlive);
 }

        public void TestInternalNestedClassAnonymousStaticMethod()
        {
            Reset();

            _itemInternal = new InternalNestedTestClass();
            _reference = new WeakReference(_itemInternal);

            _action = _itemInternal.GetFunc(WeakActionTestCase.AnonymousStaticMethod);

            Assert.IsTrue(_reference.IsAlive);
            Assert.IsTrue(_action.IsAlive);

            string result = _action.Execute();

            Assert.AreEqual(
                InternalNestedTestClass.Expected,
                InternalNestedTestClass.Result);
            Assert.AreEqual(
                InternalNestedTestClass.Expected,
                result);

            _itemInternal = null;
            GC.Collect();

            Assert.IsFalse(_reference.IsAlive);
        }

        public void TestPublicClassPublicStaticMethod()
        {
            Reset();

            _itemPublic = new PublicTestClass();
            _reference = new WeakReference(_itemPublic);

            _action = _itemPublic.GetFunc(WeakActionTestCase.PublicStaticMethod);

            Assert.IsTrue(_reference.IsAlive);
            Assert.IsTrue(_action.IsAlive);

            var result = _action.Execute();

            Assert.AreEqual(
                PublicTestClass.Expected + PublicTestClass.PublicStatic,
                PublicTestClass.Result);
            Assert.AreEqual(
                PublicTestClass.Expected + PublicTestClass.PublicStatic,
                result);

            _itemPublic = null;
            GC.Collect();

            Assert.IsFalse(_reference.IsAlive);
        }

        public void TestInternalClassAnonymousStaticMethod()
        {
            Reset();

            const string parameter = "My parameter";

            _itemInternal = new InternalTestClass<string>();
            _reference = new WeakReference(_itemInternal);

            _action = _itemInternal.GetFunc(WeakActionTestCase.AnonymousStaticMethod);

            Assert.IsTrue(_reference.IsAlive);
            Assert.IsTrue(_action.IsAlive);

            string result = _action.Execute(parameter);

            Assert.AreEqual(
                InternalTestClass<string>.Expected + parameter,
                InternalTestClass<string>.Result);
            Assert.AreEqual(
                InternalTestClass<string>.Expected + parameter,
                result);

            _itemInternal = null;
            GC.Collect();

            Assert.IsFalse(_reference.IsAlive);
        }

        public void TestPublicClassPublicStaticMethod()
        {
            Reset();

            const string parameter = "My parameter";

            _itemPublic = new PublicTestClass<string>();
            _reference = new WeakReference(_itemPublic);

            _action = _itemPublic.GetFunc(WeakActionTestCase.PublicStaticMethod);

            Assert.IsTrue(_reference.IsAlive);
            Assert.IsTrue(_action.IsAlive);

            var result = _action.Execute(parameter);

            Assert.AreEqual(
                PublicTestClass<string>.Expected + PublicTestClass<string>.PublicStatic + parameter,
                PublicTestClass<string>.Result);
            Assert.AreEqual(
                PublicTestClass<string>.Expected + PublicTestClass<string>.PublicStatic + parameter,
                result);

            _itemPublic = null;
            GC.Collect();

            Assert.IsFalse(_reference.IsAlive);
        }

        public void TestPublicNestedClassPublicNamedMethod()
        {
            Reset();

            const int index = 99;

            _itemPublic = new PublicNestedTestClass(index);

            _action = _itemPublic.GetFunc(WeakActionTestCase.PublicNamedMethod);

            _reference = new WeakReference(_itemPublic);
            Assert.IsTrue(_reference.IsAlive);
            Assert.IsTrue(_action.IsAlive);

            var result = _action.Execute();

            Assert.AreEqual(
                PublicNestedTestClass.Expected + PublicNestedTestClass.Public + index,
                PublicNestedTestClass.Result);
            Assert.AreEqual(
                PublicNestedTestClass.Expected + PublicNestedTestClass.Public + index,
                result);

            _itemPublic = null;
            GC.Collect();

            Assert.IsFalse(_reference.IsAlive);
        }

        public void TestPublicClassInternalNamedMethod()
        {
            Reset();

            const int index = 99;

            _itemPublic = new PublicTestClass(index);
            _reference = new WeakReference(_itemPublic);

            _action = _itemPublic.GetFunc(WeakActionTestCase.InternalNamedMethod);

            Assert.IsTrue(_reference.IsAlive);
            Assert.IsTrue(_action.IsAlive);

            var result = _action.Execute();

            Assert.AreEqual(
                PublicTestClass.Expected + PublicTestClass.Internal + index,
                PublicTestClass.Result);
            Assert.AreEqual(
                PublicTestClass.Expected + PublicTestClass.Internal + index,
                result);

            _itemPublic = null;
            GC.Collect();

#if SILVERLIGHT
            Assert.IsTrue(_reference.IsAlive); // Anonymous, private and internal methods cannot be GCed
            _action = null;
            GC.Collect();
            Assert.IsFalse(_reference.IsAlive);
#else
            Assert.IsFalse(_reference.IsAlive);
#endif
        }

        public void TestPublicClassInternalNamedMethod()
        {
            Reset();

            const string parameter = "My parameter";
            const int index = 99;

            _itemPublic = new PublicTestClass<string>(index);
            _reference = new WeakReference(_itemPublic);

            _action = _itemPublic.GetFunc(WeakActionTestCase.InternalNamedMethod);

            Assert.IsTrue(_reference.IsAlive);
            Assert.IsTrue(_action.IsAlive);

            string result = _action.Execute(parameter);

            Assert.AreEqual(
                PublicTestClass<string>.Expected + PublicTestClass<string>.Internal + index + parameter,
                PublicTestClass<string>.Result);
            Assert.AreEqual(
                PublicTestClass<string>.Expected + PublicTestClass<string>.Internal + index + parameter,
                result);

            _itemPublic = null;
            GC.Collect();

            Assert.IsFalse(_reference.IsAlive);
        }