INotifyPropertyChanged的不刷新列表視圖我在WPF MVVM實體

Question

我在我的視圖模型一個行動中的實體框架幹活添加記錄有一個動作在這樣的視圖來顯示記錄：

private void FillProspects() 

    { 
     var q = (from a in ctx2.Prospects// 'ctx' is the object of entity 
       select a).ToList(); 
     this.Prospects = q;    // 'Porspects' is a collection of entity class this I have bound with my List view in my view 
    } 

這將在構建我的視圖模型時調用。因此，我的視圖中的列表視圖將顯示記錄。 我已經在我看來model..I一個添加記錄行動已經在對應於實體類生成例如性能我視圖模型創建的屬性：

 private String _FirstName; 
     public String FirstName 
     { 
     get 
     { 
      return _FirstName; 
     } 
     set 
     { 
      _FirstName = value; 

     } 
    } 

並在視圖模型我添加記錄操作是：

public void Add1() 
    { 
     newprospect = new Prospect(); 
     newprospect.ID = Guid.NewGuid(); 
     newprospect.FirstName = FirstName; 
     newprospect.LastName = LastName; 
     newprospect.Address = Address; 
     newprospect.State = State; 
     newprospect.City = City; 
     newprospect.ZIP = ZIP; 
     prospect = newprospect; 
     ctx2.AddToProspects(prospect); 
     FillProspects(); 
     //RaisePropertyChanged("Prospects"); 
    } 

我繼承了：INotifyPropertyChanged和進口它的

using System.Windows.Input; 
public event PropertyChangedEventHandler PropertyChanged = delegate { }; 
private void RaisePropertyChanged(string property) { PropertyChanged(this, new PropertyChangedEventArgs(property)); } 

但我的通知不刷新我的查看Listview記錄後添加記錄。因此，我只是在addrecord行動中調用填充記錄方法'FillProspects'。這是做MVVM的正確方法。爲什麼我的Listview沒有刷新後，添加記錄行動，我失蹤了？我有試圖與 RaisePropertyChanged("Prospects");在添加記錄動作......但它不是令人耳目一新。所以我只是叫補法再次行動

我的完整視圖模型：

  using System; 
     using System.Collections.Generic; 
     using System.Linq; 
    using System.Text; 
     using System.ComponentModel; 
    using System.Windows.Input; 
    using System.Collections.ObjectModel; 

    namespace Wpfentity3 
    { 
public class frmProspects_VM : INotifyPropertyChanged 
{ 
    TestsEntities ctx2 = new TestsEntities(); 
    public ObservableCollection<Prospect> prospects { get; set; } 
    //This is the collection where records - er, entities - returned by a query are stored; 
    //Prospect is the generated class that defines a record - er, 
    //an entity as well as the query for that table. 

    private CommandMap _Commands; 
    public CommandMap Commands { get { return _Commands; } } 

    Prospect newprospect; 
    //This holds a new prospect that is created and then added to the prospects collection 
    private Prospect _prospect; 
    public Prospect prospect { 
           get 
           { 
            return _prospect; 
           } 
           set 
           { 
            _prospect = value; 
            RaisePropertyChanged("prospect"); 
           } 
           } 

    //prospect is the object that holds the current record from the Prospects table. 
    //MainWindow controls are bound to this object 


    public frmProspects_VM() 
    { 
     //FillProspects(); 
     ctx2 = new TestsEntities(); 
     //This instantiates the EntityManager class ; 
     prospects = new ObservableCollection<Prospect>(); 
     //This instantiates the prospects collection of Prospect records - er, entities; 

     _Commands = new CommandMap(); 
     _Commands.AddCommand("Add", x => Add1()); 
    } 

    private ObservableCollection<Prospect> _prospects; 
    public ObservableCollection<Prospect> Prospects 
    { 
     get 
     { 
     return _prospects; 
     } 
     set 
    { 
     _prospects = value; 
     RaisePropertyChanged("Prospects"); 
     } 
    } 

    private String _FirstName; 
    public String FirstName 
    { 
     get 
     { 
      return _FirstName; 
     } 
     set 
     { 
      _FirstName = value; 

     } 
    } 
    private String _LastName; 
    public String LastName 
    { 
     get 
     { 
      return _LastName; 
     } 
     set 
     { 
      _LastName = value; 

     } 
    } 
    private String _Address; 
    public String Address 
    { 
     get 
     { 
      return _Address; 
     } 
     set 
     { 
      _Address = value; 

     } 
    } 

    private String _State; 
    public String State 
    { 
     get 
     { 
      return _State; 
     } 
     set 
     { 
      _State = value; 

     } 
    } 

    private String _City; 
    public String City 
    { 
     get 
     { 
      return _City; 
     } 
     set 
     { 
      _City = value; 

     } 
    } 
    private String _ZIP; 
    public String ZIP 
    { 
     get 
     { 
      return _ZIP; 
     } 
     set 
     { 
      _ZIP = value; 

     } 
    } 

     public void Add1() 
    { 

    newprospect = new Prospect(); 
    newprospect.ID = Guid.NewGuid(); 
    newprospect.FirstName = FirstName; 
    newprospect.LastName = LastName; 
    newprospect.Address = Address; 
    newprospect.State = State; 
    newprospect.City = City; 
    newprospect.ZIP = ZIP; 

    prospect = newprospect; 
    ctx2.AddToProspects(prospect); 
    Prospects.Add(newprospect); 
    } 

    public event PropertyChangedEventHandler PropertyChanged = delegate { }; 
    private void RaisePropertyChanged(string property) { PropertyChanged(this, new PropertyChangedEventArgs(property)); } 
} 

}

我的觀點xamal ：

<Window x:Class="Wpfentity3.MainWindow" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
WindowStartupLocation="CenterScreen" 

    Title="Prospects" 
    Height="482" Width="500" MaxWidth="500" MaxHeight="600" 
    xmlns:cusns="clr-namespace:Wpfentity3"> 



    <StackPanel Height="290" VerticalAlignment="Top"> 
    <StackPanel Orientation="Horizontal" > 
     <Label 
    Content="Prospects" 
    BorderBrush="Blue" BorderThickness="1" 
    HorizontalAlignment="Left" VerticalAlignment="Top" 
    FontSize="24" FontFamily="Comic Sans MS" 
    Padding="13,3,13,9" Margin="5" 
     Foreground="Purple" Background="LemonChiffon" /> 
      <Label 
    Content="{Binding Path=label}" Foreground="Red" FontSize="14" 
    HorizontalAlignment="Right" VerticalAlignment="Center" 
    Height="auto" Margin="180,0,10,0" /> 


    </StackPanel> 

    <Grid 
    HorizontalAlignment="Left" VerticalAlignment="Top" 
    Height="120" Width="475" > 
     <Grid.RowDefinitions> 
      <RowDefinition Height="25*" /> 
      <RowDefinition Height="25*" /> 
      <RowDefinition Height="25*" /> 
      <RowDefinition Height="25*" /> 

     </Grid.RowDefinitions> 
     <Grid.ColumnDefinitions> 
      <ColumnDefinition Width="90*" /> 
      <ColumnDefinition Width="135*" /> 
      <ColumnDefinition Width="45*" /> 
      <ColumnDefinition Width="32*" /> 
      <ColumnDefinition Width="57*" /> 
      <ColumnDefinition Width="118*" /> 
     </Grid.ColumnDefinitions> 

     <Label 
    Content="First name" 
    Grid.Row="0" Grid.Column="0" Margin="0,0,5,0" 
    HorizontalAlignment="Right" VerticalAlignment="Center" /> 
     <TextBox Name="txtFirstName" 
    Grid.Column="1" 
    HorizontalAlignment="Left" VerticalAlignment="Center" Text="{Binding Path=FirstName}" 
    Width="130" /> 

     <Label 
    Content="Last name" 
    Grid.Row="1" Grid.Column="0" Margin="0,0,5,0" 
    HorizontalAlignment="Right" VerticalAlignment="Center" /> 
     <TextBox Name="txtLastName" 
    Grid.Row="1" Grid.Column="1" 
    HorizontalAlignment="Left" VerticalAlignment="Center" Text="{Binding LastName}" 
    Width="130" /> 

     <Label 
    Content="Address" 
    Grid.Row="2" Grid.Column="0" Margin="0,0,5,0" 
    HorizontalAlignment="Right" VerticalAlignment="Center" /> 
     <TextBox Name="txtAddress" 
    Grid.Row="2" Grid.Column="1" 
    HorizontalAlignment="Left" VerticalAlignment="Center" Text="{Binding Address}" 
    Width="300" Grid.ColumnSpan="5" /> 

     <Label 
    Content="City" 
    Grid.Row="3" Grid.Column="0" Margin="0,0,5,0" 
    HorizontalAlignment="Right" VerticalAlignment="Center" /> 
     <TextBox Name="txtCity" 
    Grid.Row="3" Grid.Column="1" 
    HorizontalAlignment="Left" VerticalAlignment="Center" Text="{Binding City}" 
    Width="130" /> 

     <Label 
    Content="State" 
    Grid.Row="3" Grid.Column="2" Margin="0,0,5,0" 
    HorizontalAlignment="Right" VerticalAlignment="Center" /> 
     <TextBox Name="txtState" 
    Grid.Row="3" Grid.Column="3" Width="30" MaxLength="2" CharacterCasing="Upper" Text="{Binding State}" 
    HorizontalAlignment="Left" VerticalAlignment="Center" /> 

     <Label 
     Content="ZIP code" 
    Grid.Row="3" Grid.Column="4" Margin="0,0,5,0" 
    HorizontalAlignment="Right" VerticalAlignment="Center" /> 
     <TextBox Name="txtZIP" 
    Grid.Row="3" Grid.Column="5" MaxLength="10" 
    HorizontalAlignment="Left" VerticalAlignment="Center" Text="{Binding ZIP}" 
    Width="90" /> 

    </Grid> 

    <StackPanel Orientation="Horizontal" Margin="0,10,0,0"> 

     <Button Name="btnFind" 
    Content="_Find" 
    Width="auto" Margin="5,0,5,0" Padding="10,0,10,0" /> 
     <Button Name="btnAdd" 
    Content="_Add" Command="{Binding Commands.Add}" 
    Width="auto" Margin="5,0,5,0" Padding="10,0,10,0" /> 
     <Button Name="btnEdit" 
    Content="_Edit" 
    Width="auto" Margin="5,0,5,0" Padding="10,0,10,0" /> 
     <Button Name="btnDelete" 
    Content="_Delete" 
    Width="auto" Margin="5,0,5,0" Padding="10,0,10,0" /> 
     <Button Name="btnSave" 
    Content="_Save" 
    Width="auto" Margin="5,0,5,0" Padding="10,0,10,0" /> 
     <Button Name="btnCancel" 
    Content="_Cancel" 
    Width="auto" Margin="5,0,5,0" Padding="10,0,10,0" /> 
     <Button Name="btnClose" 
    Content="Cl_ose" 
    Width="auto" Margin="5,0,5,0" Padding="10,0,10,0" 
    /> 



    </StackPanel> 

    <StackPanel Height="34" Margin="10"> 
     <Grid Margin="10"> 
      <ListView Name="lvprospects" ItemsSource="{Binding Prospects}" Margin="0,0,0,-200"> 
       <ListView.View> 
        <GridView> 
         <GridViewColumn Header="FirstName" Width="120" DisplayMemberBinding="{Binding FirstName}" /> 
         <GridViewColumn Header="LastName" Width="50" DisplayMemberBinding="{Binding LastName}" /> 
         <GridViewColumn Header="Address" Width="50" DisplayMemberBinding="{Binding Address}" /> 
         <GridViewColumn Header="City" Width="50" DisplayMemberBinding="{Binding City}" /> 
         <GridViewColumn Header="State" Width="50" DisplayMemberBinding="{Binding State}" /> 
         <GridViewColumn Header="ZIP" Width="50" DisplayMemberBinding="{Binding ZIP}" /> 
        </GridView> 
       </ListView.View> 
      </ListView> 
     </Grid> 




    </StackPanel> 

</StackPanel> 

Answer 1

變化從List<Prospect>的Prospects屬性來ObservableCollection<Prospect>類型：

private ObservableCollection<Prospect> _prospects = new ObservableCollection<Prospect>(); 
public ObservableCollection<Prospect> Prospects 
{ 
    get 
    { 
     return _prospects; 
    } 
    set 
    { 
     _prospects = value; 
     RaisePropertyChanged("Prospects"); 
    } 
} 

並添加新的Prospect對象在此集合，以及在​​方法：

public void Add1() 
{ 

    newprospect = new Prospect(); 
    newprospect.ID = Guid.NewGuid(); 
    newprospect.FirstName = FirstName; 
    newprospect.LastName = LastName; 
    newprospect.Address = Address; 
    newprospect.State = State; 
    newprospect.City = City; 
    newprospect.ZIP = ZIP; 

    prospect = newprospect; 
    ctx2.AddToProspects(prospect); 
    Prospects.Add(newprospect); 
} 

只需將它添加到DbContext不影響ListView。

Answer 2

如果你要綁定以便在您的視圖模型集合，我建議使用一個ObservableCollection。
ObservableCollection實現INotifyCollectionChanged，它在添加或刪除元素時通知視圖。
有了這個，你不應該需要你的「FillProspects」方法和你的「RaisePropertyChanged（」Prospects「）」。

如果您想了解更多信息，我建議您發佈如何綁定到您的XAML中，以及如何構建您的「Prospects」對象（我們甚至不知道它是什麼類型，我只是假設它不是ObservableCollection） 。

編輯： 您將您的ListView綁定到「前景」，但在您的ViewModel中，我看到「前景」是類型「列表」，它需要是「ObservableCollection」。我看到你有一個名爲「前景」的ObservableCollection，但你不會在任何地方使用它。這可能是問題嗎？

Answer 3

這是好的新項目添加到數據庫，然後用同樣的刷新方法FillProspects再次檢索集合：

你在做什麼是基本正確。