MVVM之View和ViewModel的关联

概要：

将所有的VM在加载到Application的Static Resource中，然后在Ｖｉｅｗ中用标签指定。

实现：

１）采用特性指定要添加到ＳｔａｔｉｃＲｅｓｏｕｒｃｅ中的对象

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publicclassStaticResourceAttribute : Attribute

    {

        publicstringKey { get; set; }

        publicStaticResourceAttribute(stringkey)

        {

            this.Key = key;

        }

    }

２）从当前的程序集中，把所有标记了StaticResourceAttribute的VM加载到AppResource中

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publicclassViewModelManager

    {

        privatestaticApplication app = Application.Current;

        publicstaticvoidInjectViewModelsToResources()

        {

            Assembly executingAssembly = Assembly.GetCallingAssembly();

            foreach(Type type inexecutingAssembly.GetTypes())

            {

                var attributes = type.GetCustomAttributes(false);

                foreach(var attribute inattributes)

                {

                    if(attribute isStaticResourceAttribute)

                    {

                        var obj = Activator.CreateInstance(type);

                        if(!app.Resources.Contains(type.Name))

                            app.Resources.Add(type.Name, obj);

                    }

                }

            }

        }

        publicstaticT GetViewModelFromResources<T>()

        {

            var key = typeof(T).Name;

            if(app.Resources.Contains(key))

                return(T)app.Resources[key];

            else

                returndefault(T);

        }

    }

在主窗体中调用：

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publicpartialclassMainPage : UserControl

    {

        publicMainPage()

        {

            ViewModelManager.InjectViewModelsToResources();

            InitializeComponent();         

        }

    }

3）View写法

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<UserControlx:Class="XXX .LoginView"〉

 <UserControl.DataContext>

        <BindingSource="{StaticResource LoginViewModel}"/>

    </UserControl.DataContext>

</UserControl>

结论：

这样处理后，实现了VM的"单例",多个View关联同一个VM时可以共享数据。