MVVM框架搭建

以下是概要的目录结构，其中View，ViewModel，Model正代表的是MVVM的标识。

View：页面window或者UserControl

Model：数据模型对象

ViewModel：与View交互binding，逻辑业务处理。

当然可以根据自己项目的具体情况，再进行拆分，包括业务逻辑，

服务数据分离，日志分离等。

其中主要的两个文件：

ViewModelBase.cs

ViewModel的绑定

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Threading;

namespace Common
{
    public abstract class ViewModelBase : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        public virtual void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }

    public static class ViewModelBaseEx
    {
        public static void OnPropertyChanged<T, TProperty>(this T PropetyChangedBase, Expression<Func<T, TProperty>> propertyName)
            where T : ViewModelBase
        {
            var propertyNameExpression = propertyName.Body as MemberExpression;
            if (propertyNameExpression != null)
            {
                if (Dispatcher.CurrentDispatcher.Thread == Thread.CurrentThread)
                {
                    PropetyChangedBase.OnPropertyChanged(propertyNameExpression.Member.Name);
                }
                else
                {
                    Application.Current.Dispatcher.BeginInvoke(new Action(() =>
                    {
                        PropetyChangedBase.OnPropertyChanged(propertyNameExpression.Member.Name);
                    }));
                }
            }
        }
    }
}

事件binding

DeletgateCommand.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;

namespace Common
{
    public class DelegateCommand : System.Windows.Input.ICommand
    {
        public DelegateCommand(Action executeMethod)
            : this(executeMethod, null, false)
        {
        }
        public DelegateCommand(Action executeMethod, Func<bool> canExecuteMethod)
            : this(executeMethod, canExecuteMethod, false)
        {
        }
        public DelegateCommand(Action executeMethod, Func<bool> canExecuteMethod, bool isAutomaticRequeryDisabled)
        {
            if (executeMethod == null)
            {
                throw new ArgumentNullException("executeMethod");
            }
            _executeMethod = executeMethod;
            _canExecuteMethod = canExecuteMethod;
            _isAutomaticRequeryDisabled = isAutomaticRequeryDisabled;
        }
        public bool CanExecute()
        {
            if (_canExecuteMethod != null)
            {
                return _canExecuteMethod();
            }
            return true;
        }
        public void Execute()
        {
            if (_executeMethod != null)
            {
                _executeMethod();
            }
        }
        public bool IsAutomaticRequeryDisabled
        {
            get
            {
                return _isAutomaticRequeryDisabled;
            }
            set
            {
                if (_isAutomaticRequeryDisabled != value)
                {
                    if (value)
                    {
                        CommandManagerHelper.RemoveHandlersFromRequerySuggested(_canExecuteChangedHandlers);
                    }
                    else
                    {
                        CommandManagerHelper.AddHandlersToRequerySuggested(_canExecuteChangedHandlers);
                    }
                    _isAutomaticRequeryDisabled = value;
                }
            }
        }
        public void RaiseCanExecuteChanged()
        {
            OnCanExecuteChanged();
        }
        protected virtual void OnCanExecuteChanged()
        {
            CommandManagerHelper.CallWeakReferenceHandlers(_canExecuteChangedHandlers);
        }
        public event EventHandler CanExecuteChanged
        {
            add
            {
                if (!_isAutomaticRequeryDisabled)
                {
                    CommandManager.RequerySuggested += value;
                }
                CommandManagerHelper.AddWeakReferenceHandler(ref _canExecuteChangedHandlers, value, );
            }
            remove
            {
                if (!_isAutomaticRequeryDisabled)
                {
                    CommandManager.RequerySuggested -= value;
                }
                CommandManagerHelper.RemoveWeakReferenceHandler(_canExecuteChangedHandlers, value);
            }
        }
        bool System.Windows.Input.ICommand.CanExecute(object parameter)
        {
            return CanExecute();
        }
        void System.Windows.Input.ICommand.Execute(object parameter)
        {
            Execute();
        }
        private readonly Action _executeMethod = null;
        private readonly Func<bool> _canExecuteMethod = null;
        private bool _isAutomaticRequeryDisabled = false;
        private List<WeakReference> _canExecuteChangedHandlers;
    }
    public class DelegateCommand<T> : System.Windows.Input.ICommand
    {
        public DelegateCommand(Action<T> executeMethod)
            : this(executeMethod, null, false)
        {
        }
        public DelegateCommand(Action<T> executeMethod, Func<T, bool> canExecuteMethod)
            : this(executeMethod, canExecuteMethod, false)
        {
        }
        public DelegateCommand(Action<T> executeMethod, Func<T, bool> canExecuteMethod, bool isAutomaticRequeryDisabled)
        {
            if (executeMethod == null)
            {
                throw new ArgumentNullException("executeMethod");
            }
            _executeMethod = executeMethod;
            _canExecuteMethod = canExecuteMethod;
            _isAutomaticRequeryDisabled = isAutomaticRequeryDisabled;
        }
        public bool CanExecute(T obj)
        {
            if (_canExecuteMethod != null)
            {
                return _canExecuteMethod(obj);
            }
            return true;
        }
        public void Execute(T obj)
        {
            if (_executeMethod != null)
            {
                _executeMethod(obj);
            }
        }
        public bool IsAutomaticRequeryDisabled
        {
            get
            {
                return _isAutomaticRequeryDisabled;
            }
            set
            {
                if (_isAutomaticRequeryDisabled != value)
                {
                    if (value)
                    {
                        CommandManagerHelper.RemoveHandlersFromRequerySuggested(_canExecuteChangedHandlers);
                    }
                    else
                    {
                        CommandManagerHelper.AddHandlersToRequerySuggested(_canExecuteChangedHandlers);
                    }
                    _isAutomaticRequeryDisabled = value;
                }
            }
        }
        public void RaiseCanExecuteChanged()
        {
            OnCanExecuteChanged();
        }
        protected virtual void OnCanExecuteChanged()
        {
            CommandManagerHelper.CallWeakReferenceHandlers(_canExecuteChangedHandlers);
        }
        public event EventHandler CanExecuteChanged
        {
            add
            {
                if (!_isAutomaticRequeryDisabled)
                {
                    CommandManager.RequerySuggested += value;
                }
                CommandManagerHelper.AddWeakReferenceHandler(ref _canExecuteChangedHandlers, value, );
            }
            remove
            {
                if (!_isAutomaticRequeryDisabled)
                {
                    CommandManager.RequerySuggested -= value;
                }
                CommandManagerHelper.RemoveWeakReferenceHandler(_canExecuteChangedHandlers, value);
            }
        }
        bool System.Windows.Input.ICommand.CanExecute(object parameter)
        {
            return CanExecute((T)parameter);
        }
        void System.Windows.Input.ICommand.Execute(object parameter)
        {
            Execute((T)parameter);
        }
        private readonly Action<T> _executeMethod = null;
        private readonly Func<T, bool> _canExecuteMethod = null;
        private bool _isAutomaticRequeryDisabled = false;
        private List<WeakReference> _canExecuteChangedHandlers;
    }
    //采用弱引用，避免内存泄漏
    internal class CommandManagerHelper
    {
        internal static void CallWeakReferenceHandlers(List<WeakReference> handlers)
        {
            if (handlers != null)
            {
                // Take a snapshot of the handlers before we call out to them since the handlers
                // could cause the array to me modified while we are reading it.
                EventHandler[] callees = new EventHandler[handlers.Count];
                int count = ;
                for (int i = handlers.Count - ; i >= ; i--)
                {
                    WeakReference reference = handlers[i];
                    EventHandler handler = reference.Target as EventHandler;
                    if (handler == null)
                    {
                        // Clean up old handlers that have been collected
                        handlers.RemoveAt(i);
                    }
                    else
                    {
                        callees[count] = handler;
                        count++;
                    }
                }
                // Call the handlers that we snapshotted
                for (int i = ; i < count; i++)
                {
                    EventHandler handler = callees[i];
                    handler(null, EventArgs.Empty);
                }
            }
        }
        internal static void AddHandlersToRequerySuggested(List<WeakReference> handlers)
        {
            if (handlers != null)
            {
                foreach (WeakReference handlerRef in handlers)
                {
                    EventHandler handler = handlerRef.Target as EventHandler;
                    if (handler != null)
                    {
                        CommandManager.RequerySuggested += handler;
                    }
                }
            }
        }
        internal static void RemoveHandlersFromRequerySuggested(List<WeakReference> handlers)
        {
            if (handlers != null)
            {
                foreach (WeakReference handlerRef in handlers)
                {
                    EventHandler handler = handlerRef.Target as EventHandler;
                    if (handler != null)
                    {
                        CommandManager.RequerySuggested -= handler;
                    }
                }
            }
        }
        internal static void AddWeakReferenceHandler(ref List<WeakReference> handlers, EventHandler handler)
        {
            AddWeakReferenceHandler(ref handlers, handler, -);
        }
        internal static void AddWeakReferenceHandler(ref List<WeakReference> handlers, EventHandler handler, int defaultListSize)
        {
            if (handlers == null)
            {
                handlers = (defaultListSize >  ? new List<WeakReference>(defaultListSize) : new List<WeakReference>());
            }
            handlers.Add(new WeakReference(handler));
        }
        internal static void RemoveWeakReferenceHandler(List<WeakReference> handlers, EventHandler handler)
        {
            if (handlers != null)
            {
                for (int i = handlers.Count - ; i >= ; i--)
                {
                    WeakReference reference = handlers[i];
                    EventHandler existingHandler = reference.Target as EventHandler;
                    if ((existingHandler == null) || (existingHandler == handler))
                    {
                        // Clean up old handlers that have been collected
                        // in addition to the handler that is to be removed.
                        handlers.RemoveAt(i);
                    }
                }
            }
        }
    }
}

这样基本的内容就齐了，简单的MVVM可以实现binding等功能了。