我如何更新ListView中的項目與Caliburn.Micro在C＃中？

Question

我寫了一個簡單的程序與MVVM（C＃）和XAML使用Caliburn.Micro庫， 但有些動作沒有工作：

• 更新項目內容
• 獲得所選項目
• 得到具體項目
• 移和下移記錄
• 啓用或禁用按鈕時添加按鈕，點擊

任何幫助，將不勝感激。

我的GUI代碼：

// Views\MainView.xaml 
<Window x:Class="ListBox_CaliburnMicro.MainView" 
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
     xmlns:cal="clr-namespace:Caliburn.Micro;assembly=Caliburn.Micro" 
     xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity" 
     xmlns:vm="clr-namespace:ListBox_CaliburnMicro" 
     WindowStartupLocation="CenterScreen" 
     Title="MainWindow" Height="300" Width="600"> 
    <Grid> 
     <Grid.DataContext> 
      <vm:MainViewModel/> 
     </Grid.DataContext> 

     <Grid.ColumnDefinitions> 
      <ColumnDefinition Width="153*"/> 
     </Grid.ColumnDefinitions> 

     <Button Content="Add" Command="{Binding AddCommand}" Grid.Column="1" HorizontalAlignment="Left" Margin="10,37,0,0" VerticalAlignment="Top" Width="75" ToolTip="Add item end of list" Background="White" Foreground="Black" Height="22"/> 
     <Button Content="Delete" Command="{Binding DeleteCommand}" Grid.Column="1" HorizontalAlignment="Left" Margin="96,37,0,0" VerticalAlignment="Top" Width="75" ToolTip="Delete first item from list" Background="White" Foreground="Black" Height="22"/> 
     <Button Content="Update" Command="{Binding UpdateCommand}" Grid.Column="1" HorizontalAlignment="Left" Margin="184,37,0,0" VerticalAlignment="Top" Width="75" ToolTip="Update first item from list" Background="White" Foreground="Black" Height="22"/> 
     <Button Content="GetSelectedItem" Command="{Binding GetSelectedItemCommand}" Grid.Column="1" HorizontalAlignment="Left" Margin="271,37,0,0" VerticalAlignment="Top" Width="95" ToolTip="get selected item from list" Background="White" Foreground="Black" Height="22"/> 
     <Button Content="GetItem:" Command="{Binding GetItemXCommand}" Grid.Column="1" HorizontalAlignment="Left" Margin="377,37,0,0" VerticalAlignment="Top" Width="75" ToolTip="get item x, from list" Background="White" Foreground="Black" Height="22"/> 

     <TextBox Grid.Column="1" x:Name="ItemX" Text="0" HorizontalAlignment="Left" Height="24" Margin="457,35,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="70"/> 

     <ListView Grid.Column="1" x:Name="FileListView" ItemsSource="{Binding Path=Files}" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" Margin="10,65,10,10" Foreground="Black" Background="#FFE6EEF7"> 
      <ListView.View> 
       <GridView> 
        <GridViewColumn Header="Status" Width="Auto" 
        DisplayMemberBinding="{Binding FileStatus}"/> 
        <GridViewColumn Header="Name" Width="Auto" 
        DisplayMemberBinding="{Binding FileName}"/> 
        <GridViewColumn Header="Size" Width="Auto" 
        DisplayMemberBinding="{Binding FileSize}"/> 
        <GridViewColumn Header="System Type" Width="Auto" 
        DisplayMemberBinding="{Binding FileType}"/> 
        <GridViewColumn Header="Email Count" Width="Auto" 
        DisplayMemberBinding="{Binding FileEmailCount}"/> 
        <GridViewColumn Header="Info Count" Width="Auto" 
        DisplayMemberBinding="{Binding FileInfoCount}"/> 
       </GridView> 
      </ListView.View> 
     </ListView> 

    </Grid> 
</Window> 

我的模式是：

// Model\File.cs 
using System; 

namespace ListBox_CaliburnMicro.Model 
{ 
    public class File 
    { 
     private Guid _FileID; 
     public Guid FileID 
     { 
      get 
      { 
       return _FileID; 
      } 
      set 
      { 
       _FileID = value; 
      } 
     } 
     public string FileStatus { get; set; } 
     public string FileName { get; set; } 
     public string FileSize { get; set; } 
     public string FileType { get; set; } 
     public string FileEmailCount { get; set; } 
     public string FileInfoCount { get; set; } 

     public File() 
     { 
      FileID = Guid.NewGuid(); 
     } 
     public File(string s1 = "", string s2 = "", string s3 = "", string s4 = "", string s5 = "", string s6 = "") 
     { 
      FileID = Guid.NewGuid(); 

      FileStatus = s1; 
      FileName = s2; 
      FileSize = s3; 
      FileType = s4; 
      FileEmailCount = s5; 
      FileInfoCount = s6; 
     } 
    } 
} 

我的命令處理程序代碼：

// ViewModels\CommandHandler.cs 
using System; 
using System.Windows.Input; 

namespace ListBox_CaliburnMicro.ViewModels 
{ 
    public class CommandHandler : ICommand 
    { 
     private System.Action _action; 
     private bool _canExecute; 
     public CommandHandler(System.Action action, bool canExecute) 
     { 
      _action = action; 
      _canExecute = canExecute; 
     } 
     public bool CanExecute(object parameter) 
     { 
      return _canExecute; 
     } 

     public event EventHandler CanExecuteChanged; 
     public void Execute(object parameter) 
     { 
      _action(); 
     } 
    } 
} 

我的視圖模型：

// ViewModels\MainViewModel.cs 
using Caliburn.Micro; 
using ListBox_CaliburnMicro.Model; 
using ListBox_CaliburnMicro.ViewModels; 
using System; 
using System.Collections.Generic; 
using System.Collections.ObjectModel; 
using System.ComponentModel; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
using System.Windows.Input; 

namespace ListBox_CaliburnMicro 
{ 
    public class MainViewModel : Screen, INotifyPropertyChanged 
    { 
     public MainViewModel() 
     { 
      FillDataFile(); 

      _canAddCommandExecute = true; 
      _canDeleteCommandExecute = false; 
      _canUpdateCommandExecute = false; 
      _canGetSelectedItemCommandExecute = false; 
      _canGetItemXCommandExecute = false; 
     } 

     #region File listView 
     private ObservableCollection<File> _Files; 
     public ObservableCollection<File> Files 
     { 
      get { return _Files; } 
      set 
      { 
       _Files = value; 
       OnPropertyChanged("Files"); 
      } 
     } 

     private void FillDataFile() 
     { 
      _Files = new ObservableCollection<File>(); 
      for (int i = 0; i < 0; i++) 
      { 
       _Files.Add(new File() { FileStatus = "status", FileName = "name", FileSize = "size", FileType = "type", FileEmailCount = "email_count", FileInfoCount = "info_count" }); 
      } 
     } 

     public event PropertyChangedEventHandler PropertyChanged; 
     public void OnPropertyChanged(string propertyName) 
     { 
      if (PropertyChanged != null) 
       PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); 
     } 
     #endregion 

     #region ItemX textbox 
     private string _ItemX = "0"; 
     public string ItemX 
     { 
      get 
      { 
       return _ItemX; 
      } 
      set 
      { 
       _ItemX = value; 
      } 
     } 
     #endregion 

     #region command button 

     #region Add button with Command 
     private ICommand _AddCommand; 
     public ICommand AddCommand 
     { 
      get 
      { 
       return _AddCommand ?? (_AddCommand = new CommandHandler(() => AddAction(), _canAddCommandExecute)); 
      } 
     } 

     static int nIndex = 0; 

     private bool _canAddCommandExecute; 
     public void AddAction() 
     { 
      string strName = string.Format("{0}", nIndex++); 
      _Files.Add(new File() { FileStatus = "status", FileName = strName, FileSize = "size", FileType = "type", FileEmailCount = "email_count", FileInfoCount = "info_count" }); 

      // enabled action buttons, 
      // !!! but not worded !!! 
      _canAddCommandExecute = true; 
      _canDeleteCommandExecute = true; 
      _canUpdateCommandExecute = true; 
      _canGetSelectedItemCommandExecute = true; 
      _canGetItemXCommandExecute = true; 


     } 
     #endregion 

     #region Delete button with Command 
     private ICommand _DeleteCommand; 
     public ICommand DeleteCommand 
     { 
      get 
      { 
       return _DeleteCommand ?? (_DeleteCommand = new CommandHandler(() => DeleteAction(), _canDeleteCommandExecute)); 
      } 
     } 

     private bool _canDeleteCommandExecute; 
     public void DeleteAction() 
     { 
      if (_Files.Count > 0) 
       _Files.RemoveAt(0); 
     } 
     #endregion 

     #region Update button with Command 
     private ICommand _UpdateCommand; 
     public ICommand UpdateCommand 
     { 
      get 
      { 
       return _UpdateCommand ?? (_UpdateCommand = new CommandHandler(() => UpdateAction(), _canUpdateCommandExecute)); 
      } 
     } 

     private bool _canUpdateCommandExecute; 
     public void UpdateAction() 
     { 
      if (_Files.Count > 0) 
      { 
       // update FileName field 
       _Files[0].FileName = "+"; // !!! but didn't work !!! 

       // List<File> FilesSelect = _Files.Where(p => p.FileID == _Files[0].FileID).ToList(); 
      } 
     } 
     #endregion 

     #region GetSelectedItem button with Command 
     private ICommand _GetSelectedItemCommand; 
     public ICommand GetSelectedItemCommand 
     { 
      get 
      { 
       return _GetSelectedItemCommand ?? (_GetSelectedItemCommand = new CommandHandler(() => GetSelectedItemAction(), _canGetSelectedItemCommandExecute)); 
      } 
     } 

     private bool _canGetSelectedItemCommandExecute; 
     public void GetSelectedItemAction() 
     { 
      if (_Files.Count > 0) 
      { 
       // ... get selected item in ListView 
      } 
     } 
     #endregion 

     #region GetItemX button with Command 
     private ICommand _GetItemXCommand; 
     public ICommand GetItemXCommand 
     { 
      get 
      { 
       return _GetItemXCommand ?? (_GetItemXCommand = new CommandHandler(() => GetItemXAction(), _canGetItemXCommandExecute)); 
      } 
     } 

     private bool _canGetItemXCommandExecute; 
     public void GetItemXAction() 
     { 
      if (_Files.Count > 0) 
      { 
       // ... get item 'X' that enter in TextBox control 
      } 
     } 
     #endregion 

     #endregion 
    } 
} 

Answer 1

更新項目內容。 要在您的視圖中查看模型的更新項目，則應在您的模型的EACH屬性中實施INotifyPropertyChanged事件。例如：

public class File:INotifyPropertyChanged 
{ 
    private Guid _FileID; 
    public Guid FileID 
    { 
     get 
     { 
      return _FileID; 
     } 
     set 
     { 
      _FileID = value; 
      OnPropertyChanged("FileID"); 
     } 
    } 

    public event PropertyChangedEventHandler PropertyChanged; 
    public void OnPropertyChanged(string propertyName) 
    { 
     if (PropertyChanged != null) 
     { 
      PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); 
     } 
    }   
} 

獲取所選項目。 保存所選項目創建視圖模型的屬性，例如File：

public File SelectedFile { get; set; } 

然後綁定ListView的SelectedItem這個屬性：

<ListView Name="UserGrid" SelectedItem="{Binding SelectedFile}" 
ItemsSource="{Binding Path=Files}"/> 

你已經實現SelectedFile屬性後，你可以採取這樣的值：

if(SelectedFile!=null) 
    var exactFile=SelectedFile; 

單擊添加按鈕時啓用或禁用按鈕。 有兩種方法：隨着卡利和不卡利

隨着CaliburnMicro： CaliburnMicro有自己的機制來處理按鈕Click事件。例如：

<Button Content="ShowPageTwo"> 
    <i:Interaction.Triggers> 
     <i:EventTrigger EventName="Click"> 
       <cal:ActionMessage MethodName="ShowPageTwo" /> 
     </i:EventTrigger> 
    </i:Interaction.Triggers> 
</Button> 

要查看更多關於實現的細節，請參閱official guide at CodePlex。

沒有CaliburnMicro：

首先，你應該創建RelayCommand類通過調用委託給它的中繼功能給其他對象：

public class RelayCommand : ICommand 
{ 
    #region Fields 

    readonly Action<object> _execute; 
    readonly Predicate<object> _canExecute; 

    #endregion // Fields 

    #region Constructors 

    public RelayCommand(Action<object> execute) 
     : this(execute, null) 
    { 
    } 

    public RelayCommand(Action<object> execute, Predicate<object> canExecute) 
    { 
     if (execute == null) 
      throw new ArgumentNullException("execute"); 

     _execute = execute; 
     _canExecute = canExecute; 
    } 
    #endregion // Constructors 

    #region ICommand Members 

    public bool CanExecute(object parameter) 
    { 
     return _canExecute == null ? true : _canExecute(parameter); 
    } 

    public event EventHandler CanExecuteChanged 
    { 
     add { CommandManager.RequerySuggested += value; } 
     remove { CommandManager.RequerySuggested -= value; } 
    } 

    public void Execute(object parameter) 
    { 
     _execute(parameter); 
    } 

    #endregion // ICommand Members 
} 

然後創建您的視圖模型的屬性。例如：

public class YourViewModel 
{ 
    public RelayCommand YourCommand { get; set; } 
    public YourViewModel() 
    { 
     YourCommand = new RelayCommand(DoSmth, CanDoSmth); 
    } 

    private void DoSmth(object obj) 
    { 
     Message.Box("Hello from viewModel"); 
    } 

    private bool CanDoSmth(object obj) 
    { 
     //you could implement your logic here. But by default it should be 
     //set to true 
     return true; 
    } 
} 

和XAML應該是這樣的：

<Button Content="Click me!" Command="{Binding LoginCommand}"/>