c# - WPF双向数据绑定(bind)列表框在WPF中建模无法获取选定值

Question

我正在为 WPF 中的数据绑定(bind)而苦苦挣扎，在四处搜索之后，我仍然看不到我缺少什么来让模型更新列表中的选定项目。我有 2 个实体，一个 Slot 和一个 SlotType

public class Slot : BindableObject, INotifyPropertyChanged
{
    private int slotID;
    public int SlotID
    {
        get { return slotID; }
        set
        {
            if (slotID != value)
            {
                slotID = value;
                RaisePropertyChanged("SlotID");
            }
        }
    }
    private string user;
    public string SlotUser
    {
        get { return user; }
        set
        {
            if (user != value)
            {
                user = value;
                RaisePropertyChanged("SlotUser");
            }
        }
    }

    private int slotUserID;
    public int SlotUserID
    {
        get { return slotUserID; }
        set
        {
            if (slotUserID != value)
            {
                slotUserID = value;
                RaisePropertyChanged("SlotUserID");
            }
        }
    }

    private int slotType;
    public int SlotType
    {
        get { return slotType; }
        set
        {
            if (slotType != value)
            {
                slotType = value;
                RaisePropertyChanged("SlotType");
            }
        }
    }

    private DateTime slotStartDateTime;
    public DateTime SlotStartDateTime
    {
        get { return slotStartDateTime; }
        set
        {
            if (slotStartDateTime != value)
            {
                slotStartDateTime = value;
                RaisePropertyChanged("SlotStartDateTime");
            }
        }
    }
public class SlotType : BindableObject, INotifyPropertyChanged
{
    private int slotTypeID;
    public int SlotTypeID
    {
        get { return slotTypeID; }
        set
        {
            if (slotTypeID != value)
            {
                slotTypeID = value;
                RaisePropertyChanged("SlotTypeID");
            }
        }
    }
    private string slotTypeDesc;
    public string SlotTypeDesc
    {
        get { return slotTypeDesc; }
        set
        {
            if (slotTypeDesc != value)
            {
                slotTypeDesc = value;
                RaisePropertyChanged("SlotTypeDesc");
            }
        }
    }
    public override string ToString()
    {
        return SlotTypeDesc;
    }
}

然后我创建了一个包含两者的类，并将我的窗口上下文设置为此类。

public class SlotWithTypes 
{
    public ObservableCollection<SlotType> slotTypes { get; set; }
    public Slot slot { get; set; }
}

我从我的主窗口进行测试，如果需要，打开新窗口显示 SlotTypes 列表，供用户选择与正在创建的插槽相关的类型。

Slot slot = new Slot();
slot.SlotStartDateTime = item.SlotStartDateTime;
if (item.SlotType == 0)
{
    SlotWithTypes swtype = new SlotWithTypes();
    swtype.slotTypes = slotTypes;
    swtype.slot = slot;

    SelectSlotType stype = new SelectSlotType();
    stype.DataContext = swtype;
    stype.ShowDialog();
}

终于在我的 XAML 中有了我的列表框

<Grid>
    <ListBox Name="lstSlotTypes" 
             HorizontalAlignment="Left" 
             Height="200" 
             Margin="0,10,0,0" 
             VerticalAlignment="Top" 
             Width="194"                 
             ItemsSource="{Binding slotTypes}" 
             SelectedItem="{Binding Path=slot.Type, Mode=TwoWay}"
             SelectedValue="{Binding slotTypes.SlotTypeID, Mode=TwoWay}" 
             SelectedValuePath="{Binding slot.Type, Mode=TwoWay}" 
             DisplayMemberPath="{Binding slotTypes.SlotTypeDesc}"                  
             SelectionChanged="lstSlotTypes_SelectionChanged">
    </ListBox>
    <TextBox HorizontalAlignment="Left" 
             Height="23" 
             Margin="10,246,0,0" 
             TextWrapping="Wrap" 
             Text="{Binding slot.SlotStartDateTime, Mode=TwoWay}" 
             VerticalAlignment="Top" 
             Width="74"/>
</Grid>

为了测试，我放入了一个绑定(bind)到 slotstartdatetime 的文本框，它可以工作并更新回我的模型。我在列表框上尝试了多种绑定(bind)格式，并且可以获得要显示的 SlotTypes 列表，但无法使 Slot 实体更新为所选值。

我意识到这已经成为一个很长的问题，但如果有人能看出我做错了什么，请问一下？

Answer 1

代码有几个问题:

1. visual studio OUTPUT 窗口中有两个绑定(bind)错误(在定义列表框源并包含元素的情况下)，原因是 SelectedValuePath 的错误绑定(bind)和源类型冲突。以下是适合我的解决方案。

2. 数据上下文收集初始化:

   private void InitDataContext()
   {
       DataContext = new SlotWithTypes
       {
           slot = new Slot(),
           slotTypes = new ObservableCollection<SlotType>(new List<SlotType>
           {
               new SlotType
               {
                   SlotTypeDesc = "Bla Bla 1",
                   SlotTypeID = 1,
               },
               new SlotType
               {
                   SlotTypeDesc = "Bla Bla 2",
                   SlotTypeID = 2,
               }
           })
       };
   }
   

3. Xaml 代码:

   <Grid>
   <ListBox Name="lstSlotTypes" HorizontalAlignment="Left" 
            Height="200" Margin="0,10,0,0" 
            VerticalAlignment="Top" Width="194" 
            ItemsSource="{Binding slotTypes}" 
            SelectedValue="{Binding SelectedSlotType, Mode=TwoWay}" 
            SelectedValuePath="SlotTypeID" DisplayMemberPath="SlotTypeDesc" 
            SelectionChanged="lstSlotTypes_SelectionChanged">
   </ListBox></Grid>
   

4. SlotWithTypes 代码:

   public ObservableCollection<SlotType> slotTypes { get; set; }
   
   public Slot slot
   {
       get { return _slot; }
       set
       {
           _slot = value;
           OnPropertyChanged();
       }
   }
   
   public int SelectedSlotType
   {
       get { return _selectedSlotType; }
       set
       {
           _selectedSlotType = value;
           OnPropertyChanged();
           UpdateSlot(SelectedSlotType);
       }
   }
   
   private void UpdateSlot(int selectedSlotType)
   {
       slot.SlotType = selectedSlotType;
   }
   

5. 因此，每次我进行选择时，插槽的 SlotType 属性都会更改，并使用新值定义广告。在这里做你的逻辑。

问候，