Verwenden von ObservableCollection <Dictionary <String, Object >> als DataGrid Itemsource in WPF

Question

Ich habe eine DataGrid und ich setze ItemsSource ist ein ObservableCollection<Dictionary<String, object>> Objekt.

Normalerweise definiere ich einfach einen ClassA und setze ObservableCollection<ClassA> auf ItemsSource, dann kann ich den Namen der Eigenschaften an Spalten (DataGridTextColumn) von ClassA binden.

Aber ich weiß nicht, wie man einen Schlüssel/Wert eines Dictionary bindet.

Haben Sie Unterstützung?

Answer 1

Was youre fragen, ist ziemlich komplex, um ObservableDictionary<TKey, TValue> zu erstellen sollte man eine Klasse erstellen, implementiert:

IDictionary 
INotifyCollectionChanged 
INotifyPropertyChanged 
ICollection<KeyValuePair<TKey,TValue>> 
IEnumerable<KeyValuePair<TKey,TValue>> 
IEnumerable 

Schnittstellen. More in depth hier drin. Ein Beispiel einer solchen implemntion ist:

class ObservableDictionary<TKey, TValue> : IDictionary, INotifyCollectionChanged, INotifyPropertyChanged 
{ 
    private Dictionary<TKey, TValue> mDictionary; 

    //Methods & Properties for IDictionary implementation would defer to mDictionary: 
    public void Add(TKey key, TValue value) 
    { 
     mDictionary.Add(key, value); 
     OnCollectionChanged(NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, value) 
     return; 
    } 

    //Implementation of INotifyCollectionChanged: 
    public event NotifyCollectionChangedEventHandler CollectionChanged; 
    protected void OnCollectionChanged(NotifyCollectionChangedEventArgs args) 
    { 
     //event fire implementation 
    } 

    //Implementation of INotifyProperyChanged: 
    public event ProperyChangedEventHandler ProperyChanged; 
    protected void OnPropertyChanged(PropertyChangedEventArgs args) 
    { 
     //event fire implementation 
    } 
} 

---

Ein alterntive ist dies nice solution eines bindungsfähigen dynamischen Wörterbuch, dass jedes Wörterbucheintrag als eine Eigenschaft aus.

public sealed class BindableDynamicDictionary : DynamicObject, INotifyPropertyChanged 
{ 
    /// <summary> 
    /// The internal dictionary. 
    /// </summary> 
    private readonly Dictionary<string, object> _dictionary; 

    /// <summary> 
    /// Creates a new BindableDynamicDictionary with an empty internal dictionary. 
    /// </summary> 
    public BindableDynamicDictionary() 
    { 
     _dictionary = new Dictionary<string, object>(); 
    } 

    /// <summary> 
    /// Copies the contents of the given dictionary to initilize the internal dictionary. 
    /// </summary> 
    public BindableDynamicDictionary(IDictionary<string, object> source) 
    { 
     _dictionary = new Dictionary<string, object>(source); 
    } 

    /// <summary> 
    /// You can still use this as a dictionary. 
    /// </summary> 
    public object this[string key] 
    { 
     get { return _dictionary[key]; } 
     set 
     { 
      _dictionary[key] = value; 
      RaisePropertyChanged(key); 
     } 
    } 

    /// <summary> 
    /// This allows you to get properties dynamically. 
    /// </summary> 
    public override bool TryGetMember(GetMemberBinder binder, out object result) 
    { 
     return _dictionary.TryGetValue(binder.Name, out result); 
    } 

    /// <summary> 
    /// This allows you to set properties dynamically. 
    /// </summary> 
    public override bool TrySetMember(SetMemberBinder binder, object value) 
    { 
     _dictionary[binder.Name] = value; 
     RaisePropertyChanged(binder.Name); 
     return true; 
    } 

    /// <summary> 
    /// This is used to list the current dynamic members. 
    /// </summary> 
    public override IEnumerable<string> GetDynamicMemberNames() 
    { 
     return _dictionary.Keys; 
    } 

    public event PropertyChangedEventHandler PropertyChanged; 

    private void RaisePropertyChanged(string propertyName) 
    { 
     var propChange = PropertyChanged; 
     if (propChange == null) return; 
     propChange(this, new PropertyChangedEventArgs(propertyName)); 
    } 
} 

Dann können Sie es wie folgt verwenden:

private void testButton1_Click(object sender, RoutedEventArgs e) 
{ 
    var dd = new BindableDynamicDictionary(); // Creating a dynamic dictionary. 
    dd["Age"] = 32; //access like any dictionary 

    dynamic person = dd; //or as a dynamic 
    person.FirstName = "Alan"; // Adding new dynamic properties. The TrySetMember method is called. 
    person.LastName = "Evans"; 

    //hacky for short example, should have a view model and use datacontext 
    var collection = new ObservableCollection<object>(); 
    collection.Add(person); 
    dataGrid1.ItemsSource = collection; 
} 

Datagrid braucht individuelle Code für die Spalten Aufbau:

XAML:

<DataGrid AutoGenerateColumns="True" Name="dataGrid1" AutoGeneratedColumns="dataGrid1_AutoGeneratedColumns" /> 

AutoGeneratedColumns Veranstaltung:

private void dataGrid1_AutoGeneratedColumns(object sender, EventArgs e) 
{ 
    var dg = sender as DataGrid; 
    var first = dg.ItemsSource.Cast<object>().FirstOrDefault() as DynamicObject; 
    if (first == null) return; 
    var names = first.GetDynamicMemberNames(); 
    foreach(var name in names) 
    { 
     dg.Columns.Add(new DataGridTextColumn { Header = name, Binding = new Binding(name) });    
    }    
}