我有一个位于ElementHost中的WPF用户控件，因此它可以在WinForms应用程序中使用。在这个WPF用户控件上有一个ComboBox，我试图将一个相当简单的自定义类的ObservableCollection数据绑定到它。这个ObservableCollection是我的“视图模型”类（MVVM方法并不完美）的公共属性，我将其绑定到用户控件（视图），并且我有一个在设计时绑定的模拟子类。
ComboBox完全按照XAML设计器中的预期呈现，但在运行时，它完全是空的，下拉区域大约有3行高，无论我向其中添加多少项（在应用程序的生命周期中，项的数量从未改变）。还有其他控件，比如TextBlocks和自制的NumericUpDown，它们绑定到其他属性，在运行时运行得很好，但ComboBox不合作。
还有一件事，如果有关系的话--视图模型示例是从一个文件反序列化的。我还没有在序列化（反序列化）中包含我添加到它的属性，但这很重要，因为示例将被创建，然后我必须调用一个函数来完成初始化，因为构造函数被绕过，而这个完成包括初始化数据绑定项集合。我不知道这是否与问题有关，但我想我应该提到它，以防万一。
物料类。如果用户选择新语言，说明文本可能会更改：

namespace Company._DataBinding {
  
  public class FlavorOption {
    public event PropertyChangedEventHandler PropertyChanged;
    private string _descriptionText;

  public EnumFlavor Flavor { get; set; }

  public string DescriptionText {
    get { return _descriptionText; }
    set {
      if (_descriptionText != value) {
        _descriptionText = value;
        try {
          PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("DescriptionText"));
        } catch (Exception anException) {
          throw anException;
        }
      }
    }
  }
}

用户控件的简略XAML。代码隐藏在构造函数内部调用InitializeComponent并实现IProcessOrder。否则，它不会触及任何内容，包括JuiceChoicesText、JuiceFlavorOptions、ChosenJuice或此处的控件：

<UserControl x:Class="Company._Specifics.JuiceOrderView"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         xmlns:local="clr-namespace:Company"
         xmlns:bound="clr-namespace:Company._DataBinding"
         mc:Ignorable="d" 
         d:DesignHeight="405" d:DesignWidth="612">
<Grid Background="White" d:DataContext="{d:DesignInstance Type=bound:MockProtoVM, IsDesignTimeCreatable=True}">
    <StackPanel>
        <TextBlock Text="{Binding JuiceChoicesText}" Grid.Column="2" />
        <ComboBox Margin="5" ItemsSource="{Binding JuiceFlavorOptions}"
     SelectedValuePath="Flavor" DisplayMemberPath="DescriptionText"
     SelectedValue="{Binding ChosenJuice, Mode=TwoWay}" />
    </StackPanel>
</Grid>

相关“视图模型”代码：

namespace Maf._Specifics {
  public class ProtoVM : INotifyPropertyChanged {
    public event PropertyChangedEventHandler PropertyChanged;
    private string _juiceChoicesText;
    private EnumFlavor _chosenJuice;
    
    public ObservableCollection<FlavorOption> JuiceFlavorOptions { get; set; }

    public string JuiceChoicesText {
      get { return _juiceChoicesText; }
      set {
        if (_juiceChoicesText != value) {
          _juiceChoicesText = value;
          NotifyListeners();
        }
      }
    }

    public EnumFlavor ChosenJuice {
      get { return _chosenJuice; }
      set {
        if (_chosenJuice != value) {
          _chosenJuice = value;
          NotifyListeners();
        }
      }
    }

    public ProtoVM() {
      FinishInitialization();
    }

    public void FinishInitialization() {
      JuiceChoicesText = "Choose your juice flavor:";

      if (JuiceFlavorOptions == null) {
        JuiceFlavorOptions = new ObservableCollection<FlavorOption> {
         new FlavorOption { Flavor = EnumFlavor.CHERRY, DescriptionText = "Cherry" },
         new FlavorOption { Flavor = EnumFlavor.ORANGE, DescriptionText = "Orange" },
         new FlavorOption { Flavor = EnumFlavor.GRAPE, DescriptionText = "Grape" }
      };

      ChosenJuice = EnumFlavor.CHERRY;
    }

    protected void NotifyListeners([CallerMemberName] string propertyName = "") {
      try {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
      } catch (Exception anException) {
        throw anException;
      }
    }
  }
}

在其父控件中设置用户控件。在数据绑定之后，不会向ComboBox（的DataContext）添加或从ComboBox（的DataContext）删除任何选项：

var juiceOrderHost = new WPFWrapperUC();
var orderJuiceTab = new TabPage(tabName);
_juiceOrderView = new JuiceOrderView();
juiceOrderHost.SetChild(_juiceOrderView);
      orderJuiceTab.Controls.Add((UserControl)juiceOrderHost);
tbcThingsToOrder.TabPages.Add(orderJuiceTab);
...
_juiceOrderKindaVM.FinishInitialization();  // _juiceOrderKindaVM is a ProtoVM
_juiceOrderView.DataContext = _juiceOrderKindaVM;

WinForms UserControl，它上面只有一个System.Windows.Forms.Integration.ElementHost：

namespace Company {
  public partial class WPFWrapperUC : UserControl, IProcessOrder {
    public WPFWrapperUC(UIElement hosting = null) {
      InitializeComponent();

      if (hosting != null)
        SetChild(hosting);
    }

    public void SetChild(UIElement hosting) {
      elhHostForWPFControl.Child = hosting;
    }

    // ...various methods that forward calls to
    //  IProcessOrder methods to elhHostForWPFControl.Child,
    //  should it be a IProcessOrder, which JuiceOrderView is. 
  }
}

mock：

namespace Company._DataBinding {
  public class MockProtoVM : ProtoVM {
    public MockProtoVM() : base() {
      JuiceChoicesText = "User sees different text at runtime, like 'Choose your juice flavor:'";
      ChosenJuice = EnumFlavor.ORANGE;
    }
  }
}

我错过了什么？谢谢...