Bound DataGrid沒有更新集合變更

Question

我是WPF的noob。希望我能找到答案。

例如，我有一個List<Customer>，它綁定到dataGrid。如果我添加一個新的客戶到列表中，並且我沒有看到datagrid在那裏添加一個新行。

<DataGrid ItemsSource="{Binding Customers}" AutoGenerateColumns="False" Height="318"> 
    <DataGrid.Columns> 
     <DataGridTextColumn Header="First Name" Binding="{Binding FirstName, Mode=TwoWay}" /> 
     <DataGridTemplateColumn Header="Image" Width="SizeToCells" IsReadOnly="True"> 
      <DataGridTemplateColumn.CellTemplate> 
       <DataTemplate> 
        <Image Height="80" Source="{Binding Image,Mode=TwoWay}" /> 
       </DataTemplate> 
      </DataGridTemplateColumn.CellTemplate> 
     </DataGridTemplateColumn> 
    </DataGrid.Columns> 
</DataGrid> 

。

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.ComponentModel; 
using System.Windows.Data; 

namespace DataGrid 
{ 
    public class MainWindowViewModel 
    { 
     public ICollectionView Customers { get; private set; } 
     public ICollectionView GroupedCustomers { get; private set; } 
     public List<Customer> _customers { get; set; } 

     public MainWindowViewModel() 
     { 
      _customers = new List<Customer> 
          { 
           new Customer 
            { 
             FirstName = "Christian", 
             LastName = "Moser", 
             Gender = Gender.Male, 
             WebSite = new Uri("http://www.wpftutorial.net"), 
             ReceiveNewsletter = true, 
             Image = "Images/christian.jpg" 
            }, 
           new Customer 
            { 
             FirstName = "Peter", 
             LastName = "Meyer", 
             Gender = Gender.Male, 
             WebSite = new Uri("http://www.petermeyer.com"), 
             Image = "Images/peter.jpg" 
            }, 
           new Customer 
            { 
             FirstName = "Lisa", 
             LastName = "Simpson", 
             Gender = Gender.Female, 
             WebSite = new Uri("http://www.thesimpsons.com"), 
             Image = "Images/lisa.jpg" 
            }, 
           new Customer 
            { 
             FirstName = "Betty", 
             LastName = "Bossy", 
             Gender = Gender.Female, 
             WebSite = new Uri("http://www.bettybossy.ch"), 
             Image = "Images/betty.jpg" 
            } 
          }; 
      Customers = CollectionViewSource.GetDefaultView(_customers); 
      GroupedCustomers = new ListCollectionView(_customers); 
      GroupedCustomers.GroupDescriptions.Add(new PropertyGroupDescription("Gender"));   
     } 
    } 
} 

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Windows; 
using System.Windows.Controls; 
using System.Windows.Data; 
using System.Windows.Documents; 
using System.Windows.Input; 
using System.Windows.Media; 
using System.Windows.Media.Imaging; 
using System.Windows.Navigation; 
using System.Windows.Shapes; 
using System.Reflection; 

namespace DataGrid 
{ 
    /// <summary> 
    /// Interaction logic for MainWindow.xaml 
    /// </summary> 
    public partial class MainWindow : Window 
    { 
     private new MainWindowViewModel view { get; set; } 
     public MainWindow() 
     { 
      InitializeComponent(); 
      view = new MainWindowViewModel(); 
      DataContext = view; 
     } 

     private void button1_Click(object sender, RoutedEventArgs e) 
     { 
      view._customers.Add(new Customer 
           { 
            FirstName = "Lei", 
            LastName = "Moser", 
            Gender = Gender.Male, 
            WebSite = new Uri("http://www.wpftutorial.net"), 
            ReceiveNewsletter = true, 
            Image = "Images/christian.jpg" 
           }); 
     } 
    } 
} 

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.ComponentModel; 

namespace DataGrid 
{  
    public enum Gender 
    { 
     Male, 
     Female 
    } 

    public class Customer : INotifyPropertyChanged 
    { 
     private string _firstName; 
     private string _lastName; 
     private Gender _gender; 
     private Uri _webSite; 
     private bool _newsletter; 
     private string _image; 

     public string FirstName 
     { 
      get { return _firstName; } 
      set 
      { 
       _firstName = value; 
       NotifyPropertyChanged("FirstName"); 
      } 
     } 

     public string LastName 
     { 
      get { return _lastName; } 
      set 
      { 
       _lastName = value; 
       NotifyPropertyChanged("LastName"); 
      } 
     } 

     public Gender Gender 
     { 
      get { return _gender; } 
      set 
      { 
       _gender = value; 
       NotifyPropertyChanged("Gender"); 
      } 
     } 

     public Uri WebSite 
     { 
      get { return _webSite; } 
      set 
      { 
       _webSite = value; 
       NotifyPropertyChanged("WebSite"); 
      } 
     } 

     public bool ReceiveNewsletter 
     { 
      get { return _newsletter; } 
      set 
      { 
       _newsletter = value; 
       NotifyPropertyChanged("Newsletter"); 
      } 
     } 

     public string Image 
     { 
      get { return _image; } 
      set 
      { 
       _image = value; 
       NotifyPropertyChanged("Image"); 
      } 
     } 

     #region INotifyPropertyChanged Members 
     public event PropertyChangedEventHandler PropertyChanged; 
     #endregion 

     #region Private Helpers 
     private void NotifyPropertyChanged(string propertyName) 
     { 
      if (PropertyChanged != null) 
      { 
       PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); 
      } 
     } 
     #endregion 
    } 
} 

我設置bindingMode到雙向，我有一個button_onClick，只是增加一個新客戶綁定的列表，但事情我沒有看到數據網格添加一個新行吧。
任何人都可以幫忙嗎？

Answer 1

問題是List<T>沒有執行INotifyCollectionChanged。沒有這些，沒有任何東西告訴WPF已經添加了一個新項目。

這裏最好的選擇是將您的班級更改爲使用ObservableCollection<T>而不是List<T>。這將導致WPF自動收到通知，無論何時添加或從集合中刪除項目，都會進行適當的更新。

Answer 2

您的List對象可能不是從INotiftyPropertyChanged繼承，因此它不會告訴您的程序更新對象。

如果您可以發佈一些代碼，我們可能可以確定是否是這種情況或導致問題的原因。