windows phone7—MVVM事件綁定

接著之前的demo；接下來做個重新整理按鈕，用來更新好友名單；這裡需要綁定一個Command給Button；當然這個Command是一個實現了ICommand介面的MainViewModel一個屬性；

1、在ViewModel裡添加RefreshCommand類

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 HelloWp7.ViewModel{    public class RefreshCommand:ICommand    {        private readonly MainViewModel _viewModel;        public RefreshCommand(MainViewModel viewModel)        {            _viewModel = viewModel;        }        public bool CanExecute(object parameter)        {            return true;        }        public event EventHandler CanExecuteChanged;        public void Execute(object parameter)        {                        _viewModel.Refresh();        }    }}

2、在ModelViewModel裡添加重新整理Command屬性

 public ICommand RefreshCommand        {            get;            private set;        }

 

3、在ModelViewModel添加Refresh資料處理

   public void Refresh()        {            ObservableCollection<Friend> friends=new ObservableCollection<Friend>( friendService.GetFriendsSet());            this.Friends = friends;      // 更新好友名單              }               

4、頁面添加重新整理按鈕，並添加事件綁定

<Button Canvas.Left="24" Canvas.Top="556" Command="{Binding RefreshCommand}" Content="Refersh" Height="72"

 Name="btnRefresh" Width="160" />

 

運行後單擊Refresh按鈕後資料列表會更新

 

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