InvalidCastException的：无法投型“Mocks.Class _...”的对象为“类”

Question

在我的WPF MVVM项目中，我得到这个错误：

InvalidCastException: Unable to cast object of type 'Mocks.DDD_AutoRadio_General_Audio_AudioFile_130_13063066' to type 'DDD.AutoRadio.General.Audio.AudioFile'.

的WPF主窗口有一个自定义UserControl。

简化类AudioFile：

namespace DDD.AutoRadio.General.Audio 
{ 
    [DataContract] 
    public class AudioFile : INotifyPropertyChanged 
    { 
     private string name; 
     /// <summary> 
     /// Name of the Mp3 
     /// </summary> 
     [DataMember] 
     public string FilePath 
     { 
      get { return name; } 
      set 
      { 
       var oldvalue = name; 
       if (oldvalue != value) 
       { 
        name = value; 
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("FilePath")); 
       } 
      } 
     } 

     public event PropertyChangedEventHandler PropertyChanged; 
    } 
} 

但我不认为这是有关这一类。
我认为这更多的是自定义UserControl：

public partial class EditField : UserControl 
{ 
    public static DependencyProperty selectedList = 
     DependencyProperty.Register("DataGridSelectedItems", typeof(OC<AudioFile>), typeof(EditField)); 


    public OC<AudioFile> DataGridSelectedItems 
    { 
     get { return (OC<AudioFile>)GetValue(selectedList); } 
     set { SetValue(selectedList, value); } 
    } 

    public EditField() 
    { 
     InitializeComponent(); 
    } 

    private void Collection_SelectionChanged(object sender, SelectionChangedEventArgs e) 
    { 
     OC<AudioFile> l = new OC<AudioFile>(); 
     foreach (AudioFile i in Collection.SelectedItems) //'Collection' is a DataGrid 
      l.Add(i); 
     DataGridSelectedItems = l; 
    } 
} 

注：OC是一款基于ObservableColletion<>类

public class OC<T> : ObservableCollection<T> where T: INotifyPropertyChanged 

这里一类是堆栈跟踪

at DDD.AutoRadio.Database.Editor.View.EditField.Collection_SelectionChanged(Object sender, SelectionChangedEventArgs e) 
at System.Windows.Controls.SelectionChangedEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget) 
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target) 
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs) 
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised) 
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args) 
at System.Windows.UIElement.RaiseEvent(RoutedEventArgs e) 
at System.Windows.Controls.DataGrid.OnSelectionChanged(SelectionChangedEventArgs e) 
at System.Windows.Controls.Primitives.Selector.InvokeSelectionChanged(List`1 unselectedInfos, List`1 selectedInfos) 
at System.Windows.Controls.Primitives.Selector.SelectionChanger.End() 
at System.Windows.Controls.Primitives.Selector.SelectionChanger.SelectJustThisItem(ItemInfo info, Boolean assumeInItemsCollection) 
at System.Windows.Controls.Primitives.Selector.SetSelectedToCurrent() 
at System.Windows.Controls.Primitives.Selector.SetSynchronizationWithCurrentItem() 
at System.Windows.Controls.DataGrid.OnItemsSourceChanged(IEnumerable oldValue, IEnumerable newValue) 
at System.Windows.Controls.ItemsControl.OnItemsSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) 
at System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e) 
at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e) 
at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args) 
at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType) 
at System.Windows.DependencyObject.InvalidateProperty(DependencyProperty dp, Boolean preserveCurrentValue) 
at System.Windows.Data.BindingExpressionBase.Invalidate(Boolean isASubPropertyChange) 
at System.Windows.Data.BindingExpression.TransferValue(Object newValue, Boolean isASubPropertyChange) 
at System.Windows.Data.BindingExpression.Activate(Object item) 
at System.Windows.Data.BindingExpression.AttachToContext(AttachAttempt attempt) 
at System.Windows.Data.BindingExpression.MS.Internal.Data.IDataBindEngineClient.AttachToContext(Boolean lastChance) 
at MS.Internal.Data.DataBindEngine.Task.Run(Boolean lastChance) 
at MS.Internal.Data.DataBindEngine.Run(Object arg) 
at MS.Internal.Data.DataBindEngine.OnLayoutUpdated(Object sender, EventArgs e) 
at System.Windows.ContextLayoutManager.fireLayoutUpdateEvent() 
at System.Windows.ContextLayoutManager.UpdateLayout() 
at System.Windows.UIElement.UpdateLayout() 

Answer 1

我发现解决方案：

在自定义UserControlEditField中有一个DependentieProperty'DataGridItemsSource'，其中SelectedItems来自。

我需要做的就是从源选择对象，而不是从SelectedItems中选择。

（在我Class的AudioFile我也有一个属性“Songcode“）

public partial class EditField : UserControl 
{ 
    #region DataGridSelectedItems 
    public static DependencyProperty selectedList = 
     DependencyProperty.Register("DataGridSelectedItems", typeof(OC<AudioFile>), typeof(EditField)); 


    public OC<AudioFile> DataGridSelectedItems 
    { 
     get { return (OC<AudioFile>)GetValue(selectedList); } 
     set { SetValue(selectedList, value); } 
    } 
    #endregion 

    #region DataGridItemsSource 
    public static DependencyProperty datagriditemsource = 
     DependencyProperty.Register("DataGridItemsSource", typeof(OC<AudioFile>), typeof(EditField)); 

    public OC<AudioFile> DataGridItemsSource 
    { 
     get { return (OC<AudioFile>)GetValue(datagriditemsource); } 
     set { SetValue(datagriditemsource, value); } 
    } 
    #endregion 

    public EditField() 
    { 
     InitializeComponent(); 
} 

    private void Collection_SelectionChanged(object sender, SelectionChangedEventArgs e) 
    { 
     OC<AudioFile> l = new OC<AudioFile>(); 
     DataGridSelectedItems.Clear(); 
     foreach (AudioFile i in Collection.SelectedItems) //'Collection' is a DataGrid 
      l.Add(DataGridItemsSource.Where(x => x.Songcode == i.Songcode || x.FilePath == i.FilePath).First()); 
     If (l.Count > 0) 
      DataGridSelectedItems = l; 
    } 
}