Question

所以我正在研究一个使用MVVM结构向用户显示数据并让他们修改数据的应用程序。我目前面临的问题是：

从RadGridView中选择实体后，我将用户查看的那个成员添加到ObservableCollection中。然后我看到RadListBox得到了填充（意味着我可以将鼠标悬停在项目上），但没有显示任何内容。 Object是我从服务引用的DataContract。我尝试了很多修复，但无济于事。

有一次我开始使用Snoop并注意到无论我将DisplayMemberPath设置为什么值，DisplayMemberPath都将始终为“Name”。当我在Snoop中时，如果我将DisplayMemberPath值更改为FirstName，则会在我的WPF应用程序中弹出名称。

我一直盯着这一段时间，可能只需要一双新的眼睛。以下是相关代码：

XAML代码：

<Grid MinHeight="70">
  <TextBlock Text="No Members viewed"
             FontWeight="Bold"
             HorizontalAlignment="Center"
             VerticalAlignment="Center"
             Visibility="{Binding TextBlockVisibility, FallbackValue=Visible, Mode=OneWay}">
  </TextBlock>
  <telerik:RadListBox Name="uRecenetlyViewMembersListBox"
          DataContext="{Binding MemberInfo}"
                      SelectionMode="Single"
          DisplayMemberPath="{Binding FirstName}"
                      ItemsSource="{Binding RecentlyViewedMembers}"
                      SelectedItem="{Binding SelectedRecentlyViewedMember,Mode=TwoWay}"
                      Visibility="{Binding WorkingListNoRecordsVisibility, FallbackValue=Visible, Mode=OneWay}" 
                      MouseDoubleClick="uRecenetlyViewMembersListBox_MouseDoubleClick"> 
     <i:Interaction.Triggers>
       <i:EventTrigger EventName="SelectionChanged">
         <i:InvokeCommandAction Command="{Binding RecentlyViewedSelectionChanged}">
         </i:InvokeCommandAction>
       </i:EventTrigger>
     </i:Interaction.Triggers>
  </telerik:RadListBox>
</Grid>

2/11编辑：所以我删除了DataContext，因为它不清楚是否因为上下文指向正确的ViewModel而工作。并更改了DisplayMemberPath并删除了绑定。

<Grid MinHeight="70">
  <TextBlock Text="No Members viewed"
             FontWeight="Bold"
             HorizontalAlignment="Center"
             VerticalAlignment="Center"
             Visibility="{Binding TextBlockVisibility, FallbackValue=Visible, Mode=OneWay}">
  </TextBlock>
  <telerik:RadListBox Name="uRecenetlyViewMembersListBox"
                      SelectionMode="Single"
                      DisplayMemberPath="FirstName"
                      ItemsSource="{Binding RecentlyViewedMembers}"
                      SelectedItem="{Binding SelectedRecentlyViewedMember,Mode=TwoWay}"
                      Visibility="{Binding WorkingListNoRecordsVisibility, FallbackValue=Visible, Mode=OneWay}" 
                      MouseDoubleClick="uRecenetlyViewMembersListBox_MouseDoubleClick"> 
     <i:Interaction.Triggers>
       <i:EventTrigger EventName="SelectionChanged">
         <i:InvokeCommandAction Command="{Binding RecentlyViewedSelectionChanged}">
         </i:InvokeCommandAction>
       </i:EventTrigger>
     </i:Interaction.Triggers>
  </telerik:RadListBox>
</Grid>

和c＃代码：

private const UInt16 recentlyViewedMemberCapacity = 10;
private ObservableCollection<Member> recentlyViewedMembers;
public ObservableCollection<Member> RecentlyViewedMembers
{
    get { return this.recentlyViewedMembers; }
    set
    {
        if (value != recentlyViewedMembers)
        {
            this.recentlyViewedMembers = value;
            //ugly & inefficient: needs refactoring
            //recentlyViewedMembers = (ObservableCollection<RecentlyViewedMember>)recentlyViewedMembers.OrderByDescending(item => item.DateAdded);
            while (recentlyViewedMembers.Count > recentlyViewedMemberCapacity)
                recentlyViewedMembers.RemoveAt(recentlyViewedMemberCapacity);
            this.RaisePropertyChanged(() => this.RecentlyViewedMembers);
            ValidateWorkingListVisibility();
        }
    }
}

这是从服务返回的DataContract，只有必要的部分：

[DataContract(Name = "Member")]
public class Member : INotifyPropertyChanged
{
    public Member();

    [DataMember(Order = 0)]
    public string FirstName { get; set; }

    public event PropertyChangedEventHandler PropertyChanged;
}

Answer 1

尝试将DisplayMemberPath设置为硬编码属性名称而不是绑定：

DisplayMemberPath="FirstName"

在标准WPF的ListBox中，DisplayMemberPath应设置为要显示的路径（表示属性名称），而不是值。因此，根据我的理解，即使绑定有效，它也会将DisplayMemberPath设置为FirstName属性的值而不是属性名称。

希望这也适用于telerik的RadListBox。

设置为其他内容后，DisplayMemberPath将恢复为Name

1 个答案: