Aktualisieren von ComboBox in XAML ohne SomeGrid.Items.Refresh()

Question

Ich bin neu in WPF + C# und fängt an, es in den Griff zu bekommen.

Ich möchte ComboBox in DataGrid aktualisieren, wenn das Programm ausgeführt wird. ComboBox zeigt leider nie ein ausgewähltes Element, wenn ich SOMEGRID.Item.Refresh() verwenden, um DataGrid zu aktualisieren.

---

Hier ist die XAML

<Window x:Class="WpfApplication1.MainWindow" 
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
     Title="MainWindow" Height="350" Width="525"> 
    <Grid> 
     <DataGrid Name="Somegrid" HorizontalAlignment="Left" AutoGenerateColumns="False" CanUserAddRows="False" CanUserDeleteRows="False"> 
      <DataGrid.Columns> 

       <DataGridTemplateColumn> 
        <DataGridTemplateColumn.Header> 
         <TextBlock Text="SomebodY" /> 
        </DataGridTemplateColumn.Header> 
        <DataGridTemplateColumn.CellTemplate> 
         <DataTemplate> 
          <ComboBox ItemsSource="{Binding Somebody}" SelectionChanged="ComboBox_SelectionChanged_Somebody" /> 
         </DataTemplate> 
        </DataGridTemplateColumn.CellTemplate> 
       </DataGridTemplateColumn> 

       <DataGridTemplateColumn> 
        <DataGridTemplateColumn.Header> 
         <TextBlock Text="SomethinG" /> 
        </DataGridTemplateColumn.Header> 
        <DataGridTemplateColumn.CellTemplate> 
         <DataTemplate> 
          <ComboBox ItemsSource="{Binding Something}" SelectionChanged="ComboBox_SelectionChanged_Something" /> 
         </DataTemplate> 
        </DataGridTemplateColumn.CellTemplate> 
       </DataGridTemplateColumn> 

       <DataGridTemplateColumn> 
        <DataGridTemplateColumn.Header> 
         <TextBlock Text="SomewherE" /> 
        </DataGridTemplateColumn.Header> 
        <DataGridTemplateColumn.CellTemplate> 
         <DataTemplate> 
          <ComboBox ItemsSource="{Binding Somewhere}" SelectionChanged="ComboBox_SelectionChanged_Somewhere" /> 
         </DataTemplate> 
        </DataGridTemplateColumn.CellTemplate> 
       </DataGridTemplateColumn> 

      </DataGrid.Columns> 
     </DataGrid> 
    </Grid> 
</Window> 

---

Hinter Code

using System.Collections.Generic; 
using System.Collections.ObjectModel; 
using System.Windows; 

namespace WpfApplication1 
{ 
    /// <summary> 
    /// Interaction logic for MainWindow.xaml 
    /// </summary> 
    public partial class MainWindow : Window 
    { 

     public MainWindow() 
     { 
      InitializeComponent(); 

      someclassFoo.Somebody = new List<string>() { "Alan", "Benjamin" }; 

      observableSomeclassFoo.Add(someclassFoo); 
      Somegrid.ItemsSource = observableSomeclassFoo; 

     } 


     public SomeclassFoo someclassFoo = new SomeclassFoo(); 
     private ObservableCollection<SomeclassFoo> _observableSomeclassFoo = new ObservableCollection<SomeclassFoo>(); 
     public ObservableCollection<SomeclassFoo> observableSomeclassFoo { get { return _observableSomeclassFoo; } } 


     private void ComboBox_SelectionChanged_Somebody(object sender, RoutedEventArgs e) 
     { 
      System.Windows.Controls.ComboBox cb1 = (System.Windows.Controls.ComboBox)sender; 

      if (cb1.SelectedItem.ToString() == "Alan") 
      { 
       someclassFoo.Something = new List<string>() { "Apple" }; 
      } 
      else if (cb1.SelectedItem.ToString() == "Benjamin") 
      { 
       someclassFoo.Something = new List<string>() { "Banana" }; 
      } 

      //Somegrid.Items.Refresh(); 
     } 


     private void ComboBox_SelectionChanged_Something(object sender, RoutedEventArgs e) 
     { 
      System.Windows.Controls.ComboBox cb2 = (System.Windows.Controls.ComboBox)sender; 

      if (cb2.SelectedItem.ToString() == "Apple") 
      { 
       someclassFoo.Somewhere = new List<string>() { "Antartica" }; 
      } 
      else if (cb2.SelectedItem.ToString() == "Banana") 
      { 
       someclassFoo.Somewhere = new List<string>() { "Bedrock" }; 
      } 

      //Somegrid.Items.Refresh(); 
     } 


     private void ComboBox_SelectionChanged_Somewhere(object sender, RoutedEventArgs e) 
     { 
      System.Windows.Controls.ComboBox cb3 = (System.Windows.Controls.ComboBox)sender; 

      MessageBox.Show(cb3.SelectedItem.ToString().ToUpper() + " selected"); 
     } 


    } 
} 

---

Eine andere Klasse

using System.Collections.Generic; 

namespace WpfApplication1 
{ 
    public class SomeclassFoo 
    { 
     public IList<string> Somebody { get; set; } 

     public IList<string> Something { get; set; } 

     public IList<string> Somewhere { get; set; } 
    } 
} 

---

Wie kann ich die ComboBox aktualisieren kann etwas und ComboBox IRGENDWO ohne Somegrid.Item.Refresh() verwendet?

Answer 1

Der SomeclassFoo Typ sollte die INotifyPropertyChanged-Schnittstelle implementieren und Änderungsbenachrichtigungen erhöhen:

public class SomeclassFoo : INotifyPropertyChanged 
{ 
    private IList<string> _somebody; 
    public IList<string> Somebody 
    { 
     get { return _somebody; } 
     set { _somebody = value; NotifyPropertyChanged(); } 
    } 

    private IList<string> _something; 
    public IList<string> Something 
    { 
     get { return _something; } 
     set { _something = value; NotifyPropertyChanged(); } 
    } 

    private IList<string> _someWhere; 
    public IList<string> Somewhere 
    { 
     get { return _someWhere; } 
     set { _someWhere = value; NotifyPropertyChanged(); } 
    } 

    public event PropertyChangedEventHandler PropertyChanged; 
    private void NotifyPropertyChanged([CallerMemberName] string propertyName = "") 
    { 
     if (PropertyChanged != null) 
      PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); 
    } 
} 

Vorgehensweise: Implementieren der Benachrichtigung über die Änderung von Eigenschaften:https://msdn.microsoft.com/en-us/library/ms743695(v=vs.110).aspx

Answer 2

Statt das Gitter an erfrischenden, die Stromquelle entfernen und eine neue Quelle gesetzt:

yourGrid.ItemsSource = null;

yourGrid.ItemsSource = yourDataSource;