Silverlight MVVM

MVVM是Model-View-ViewModel的简写。

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s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。

 

下面来看一个简单的实例

MainPage.xaml 文件

<Grid x:Name="LayoutRoot" Background="White">
        <my:BookManageControl HorizontalAlignment="Stretch"  x:Name="bookManageControl1" VerticalAlignment="Stretch" />
    </Grid>

BookManageControl.xaml

  <Grid x:Name="LayoutRoot" Background="White">
        <Grid.ColumnDefinitions>
            <ColumnDefinition/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>
        <ListBox ItemsSource="{Binding Path=BookInfos}" x:Name="lst">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel>
                        <TextBlock Text="{Binding Name}"></TextBlock>
                        <TextBlock Text="{Binding Count}"></TextBlock>
                        <TextBlock Text="{Binding PublishDate}"></TextBlock>
                        <Button  Content="删除" Width="60" Height="30" Command="{Binding  Path=DataContext.DeleteCommad, ElementName=root}" CommandParameter="{Binding Path=DataContext, RelativeSource={RelativeSource TemplatedParent}}"></Button>
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
        <Grid  Grid.Column="1">
            <StackPanel DataContext="{Binding Path=SelectedItem, ElementName=lst}">
                <TextBlock Text="书名"></TextBlock>
                <TextBox Text="{Binding Name}"></TextBox>
                <TextBlock Text="数量"></TextBlock>
                <TextBox Text="{Binding Count}"></TextBox>
                <TextBlock Text="出版日期"></TextBlock>
                <sdk:DatePicker SelectedDate="{Binding PublishDate}"/>
            </StackPanel>
        </Grid>
    </Grid>


public partial class BookManageControl : UserControl
    {
        public BookManageControl()
        {
            InitializeComponent();
            this.DataContext = new BookManageViewModel();
        }
    }

BookManageViewModel.cs

public class BookManageViewModel : ViewModel
    {
        private List<BookInfo> _bookInfos;
        private ICommand _deleteCommad;
        public List<BookInfo> BookInfos
        {
            get
            {
                if (this._bookInfos == null)
                {
                    this._bookInfos = new List<BookInfo>();
                    this._bookInfos.Add(new BookInfo()
                    {
                        Name = "WPF 4.0 揭秘",
                        Count = 5400,
                        PublishDate = new DateTime(2010, 7, 21)
                    });

                    this._bookInfos.Add(new BookInfo()
                    {
                        Name = "大话设计模式",
                        Count = 3000,
                        PublishDate = new DateTime(2009, 6, 12)
                    });

                    this._bookInfos.Add(new BookInfo()
                    {
                        Name = "征服 Ajax",
                        Count = 4000,
                        PublishDate = new DateTime(2007, 3, 9)
                    });
                }

                return this._bookInfos;
            }
            set
            {
                this._bookInfos = value;
                this.RaisePropertyChanged("BookInfos");
            }
        }

        public ICommand DeleteCommad
        {
            get
            {
                if (this._deleteCommad == null)
                {
                    this._deleteCommad = new DeleteCommad();
                }

                return this._deleteCommad;
            }
        }
    }

ViewModel.cs

 public class ViewModel : IViewModel
    {
        public event System.ComponentModel.PropertyChangedEventHandler PropertyChanged;

        protected void RaisePropertyChanged(string propertyName)
        {
            if (this.PropertyChanged != null)
            {
                this.PropertyChanged(this, new System.ComponentModel.PropertyChangedEventArgs(propertyName));
            }
        }
    }

 

IViewModel.cs

    public interface IViewModel : System.ComponentModel.INotifyPropertyChanged
    {
    }

 

DeleteCommad.cs

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

        public event EventHandler CanExecuteChanged;

        public void Execute(object parameter)
        {
            if (parameter == null)
            {
                MessageBox.Show("NULL");
            }
            else
            {
                BookInfo book = parameter as BookInfo;

                MessageBox.Show(book.Name);
            }
        }
    }