Silverlight之MVVM：模型－视图－视图模型（Model-View-ViewModel）（16）

Silverlight之MVVM：模型－视图－视图模型（Model-View-ViewModel）（16）

 

概述
组成部分Model、View、ViewModel，程序=数据结构+算法。Model就是数据结构，ViewModel实现算法数据处理，View实现数据展现。
View：UI界面
ViewModel：它是View的抽象，负责View与Model之间信息转换，将View的Command传送到Model；
Model：数据层

View与ViewModule连接可以通过下面的方式

Binding Data：实现数据的传递
Command：实现操作的调用
AttachBehavior：实现控件加载过程中的操作

View没有大量代码逻辑。结合WPF、Silverlight绑定机制，MVP演变出了MVVM，充分利用了WPF、Silverlight的优势，将大量代码逻辑、状态转到ViewModel，
可以说MVVM是专门为WPF、Silverlight打造的。

View绑定到ViewModel，然后执行一些命令在向它请求一个动作。而反过来，ViewModel跟Model通讯，告诉它更新来响应UI。
这样便使得为应用构建UI非常的容易。往一个应用程序上贴一个界面越容易，外观设计师就越容易使用Blend来创建一个漂亮的界面。
同时，当UI和功能越来越松耦合的时候，功能的可测试性就越来越强。

下面是一个具体的代码实现例子：

1.Model

using System;
using System.Net;
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;

namespace MVVM模式.Model
{
    public class AddModel : DependencyObject
    {
        public static readonly DependencyProperty Num1Property = DependencyProperty.Register("Num1", typeof(int), typeof(AddModel), null);
        public int Num1
        {
            get { return (int)GetValue(Num1Property); }
            set { SetValue(Num1Property, value); }
        }

 

        public int Num2
        {
            get { return (int)GetValue(Num2Property); }
            set { SetValue(Num2Property, value); }
        }

        // Using a DependencyProperty as the backing store for Num2.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty Num2Property =
            DependencyProperty.Register("Num2", typeof(int), typeof(AddModel), null);

        public static readonly DependencyProperty ResoultProperty = DependencyProperty.Register("Resoult", typeof(int), typeof(AddModel), null);
        public int Resoult
        {
            get { return (int)GetValue(ResoultProperty); }
            set { SetValue(ResoultProperty, value); }
        }

    

    }
}

2.ViewModel

using System;
using System.Net;
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 MVVM模式.Model;
namespace MVVM模式.ViewModel
{
    public class AddViewModel
    {

        public AddModel MyModel
        {
            get { return new AddModel(); }
        }

        public ICommand AddCommand
        {
            get
            {
                return new AddParams();
            }
        }
    }

    public class AddParams : ICommand
    {
        public bool CanExecute(object parameter)
        {
           return true;
        }

        public event EventHandler CanExecuteChanged;

        public void Execute(object parameter)
        {
          AddModel  am=parameter as AddModel;
          am.Resoult = am.Num1 + am.Num2;
        }
    }
}

3.View
后台代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using MVVM模式.ViewModel;
namespace MVVM模式
{
    public partial class MainPage : UserControl
    {
        private AddViewModel am = new AddViewModel();
        public MainPage()
        {
            InitializeComponent();
            this.DataContext = am.MyModel;
            this.button1.Command = am.AddCommand;
        }

     

    }
}
前台代码：

<UserControl x:Class="MVVM模式.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400">

    <Grid x:Name="LayoutRoot" Background="White">
        <TextBox Height="23" HorizontalAlignment="Left" Margin="42,70,0,0" Name="textBox1" VerticalAlignment="Top" Width="120" Text="{Binding Num1,Mode=TwoWay}" />
        <TextBox Height="23" HorizontalAlignment="Left" Margin="213,70,0,0" Name="textBox2" VerticalAlignment="Top" Width="120" Text="{Binding Num2,Mode=TwoWay}" />
 
        <TextBox Height="23" HorizontalAlignment="Left" Margin="127,120,0,0" Name="textBox3" VerticalAlignment="Top" Width="120" Text="{Binding Resoult,Mode=TwoWay}"/>
        <TextBlock Height="23" HorizontalAlignment="Left" Margin="178,71,0,0" Name="textBlock1" Text="+" VerticalAlignment="Top" />
        <Button Content="计算" Height="23" HorizontalAlignment="Left" Margin="149,150,0,0" CommandParameter="{Binding}" Name="button1" VerticalAlignment="Top" Width="75" />
    </Grid>
</UserControl>

4.注意附加属性应用

  public int Num1
        {
            get { return (int)GetValue(Num1Property); }
            set { SetValue(Num1Property, value); }
        }

        // Using a DependencyProperty as the backing store for Num1.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty Num1Property =
            DependencyProperty.Register("Num1", typeof(int), typeof(TestModel), new PropertyMetadata(0, new PropertyChangedCallback(xxx)));

        static void xxx(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            MessageBox.Show("sss");
        }