WindowsPhone开发笔记（1）—— ViewMoel

废话：前很长一段时间一直忙于写 GuoKr Reader 和喂饭。现在终于可以整理一下开发中的有点价值的东西。

额。。。ViewModel 这东西直面意思就是界面对象。。他里面描述的东西应该只有数据和业务逻辑，他里面不应该与任何与界面交互相关的东西（比如控制一个什么控件，动画、消息框什么的。。。。。）发生关系（别想歪了我故意的。。。）

但是我们在实际使用中VM 中的发生了一些事情总得让VIEW 知道啊所以MS 为我们提供了

System.ComponentModel.INotifyDataErrorInfo

System.ComponentModel.INotifyPropertyChanged

System.ComponentModel.InotifyPropertyChanging

等通知接口

我们以INotifyPropertyChanged 为例来看下结构：

里面有个事件：PropertyChanged

VM 通过这些通知接口里面的事件我们可以告知 View 发生了什么事情至于 View 管不关心或者关心什么那就不是 ViewModel的事情了

(注意：一般来说要绑定要界面的属性必须实现INotifyPropertyChanged 属性也就是说在属性被修改后必须触发 PropertyChanged事件，同时Notify 接口中的事件是在UI 现场中运行的在跨线程运行的时候一定要注意)

我们在回过头来说VM

一般来说或我都会实现一个 BaseViewModel 吧所需要的实现的接口和基础的方法都在里面实现好

using System;
using System.Net;
using System.Collections.Generic;
using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Windows.Threading;
using System.Windows.Navigation;
using Microsoft.Phone.Controls;
using System.Runtime.CompilerServices;
using WeiFan.Utility;

namespace WeiFan.UI.ViewModel
{
public abstract class BaseViewModel : INotifyPropertyChanged, INotifyPropertyChanging,INotifyDataErrorInfo
{

        Dispatcher _dispatcher;
        public BaseViewModel()
        {

            _dispatcher = Deployment.Current.Dispatcher;

        }

protected Dispatcher Dispatcher { get { return _dispatcher; } }
protected PhoneApplicationFrame PhoneApplicationFrame { get { return (Application.Current.RootVisual as Microsoft.Phone.Controls.PhoneApplicationFrame); } }

        private Dictionary<String, List<String>> m_errors =
           new Dictionary<string, List<string>>();

        public event PropertyChangedEventHandler PropertyChanged;

public event PropertyChangingEventHandler PropertyChanging;

public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged;

        public System.Collections.IEnumerable GetErrors(string propertyName)
        {
            if (String.IsNullOrEmpty(propertyName) ||
                !m_errors.ContainsKey(propertyName)) return null;
            return m_errors[propertyName];
        }

        public bool HasErrors
        {
            get { return m_errors.Count > 0; }
        }

        protected bool SetProperty<T>(ref T storage, T value,string propertyName)
        {
            if (object.Equals(storage, value)) return false;
            this.FirePropertyChanging(new PropertyChangingEventArgs(propertyName));
            storage = value;
            this.FirePropertyChanged(new PropertyChangedEventArgs(propertyName));
            return true;
        }

        protected virtual void FirePropertyChanging(PropertyChangingEventArgs args)
        {
            if (PropertyChanging != null)
            {
                PropertyChanging(this, args);
            }
        }

        protected virtual void FirePropertyChanged(PropertyChangedEventArgs args)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, args);
            }

        }

        protected virtual void FireErrorsChanged(DataErrorsChangedEventArgs args)
        {
            if (ErrorsChanged != null)
                ErrorsChanged(this, args);
        }

        protected virtual void AddError(string propertyName, string error, bool isWarning)
        {
            if (!m_errors.ContainsKey(propertyName))
                m_errors[propertyName] = new List<string>();

            if (!m_errors[propertyName].Contains(error))
            {
                if (isWarning) m_errors[propertyName].Add(error);
                else m_errors[propertyName].Insert(0, error);
              &n

补充：移动开发 , Windows Phone ,