c# - ListBox SelectedItem 不工作

Question

我正在尝试将对象列表加载为包含多个数据的网格，并且我已为其选择了 ListBox，如您在此处所见:

<ListBox ItemsSource="{Binding People, Mode=TwoWay}" SelectedItem="{Binding Person, Mode=TwoWay}" >
  <ListBox.ItemContainerStyle>
     <Style TargetType="ListBoxItem">
        <Setter Property="HorizontalContentAlignment" Value="Stretch" />
     </Style>
  </ListBox.ItemContainerStyle>
  <ListBox.ItemTemplate>
     <DataTemplate>
         <Grid>
             <Grid.ColumnDefinitions>
                  <ColumnDefinition Width="200"></ColumnDefinition>
                  <ColumnDefinition Width="50"></ColumnDefinition>
                  <ColumnDefinition Width="30"></ColumnDefinition>
                  <ColumnDefinition Width="50"></ColumnDefinition>
                  <ColumnDefinition Width="20"></ColumnDefinition>
             </Grid.ColumnDefinitions>
             <TextBlock VerticalAlignment="Center" Text="{Binding name}" Grid.Column="0" TextAlignment="Right"></TextBlock>
             <TextBox Grid.Column="1" Margin="5,0,0,0" Height="Auto" VerticalAlignment="Center" HorizontalAlignment="Stretch" Text="{Binding age}"></TextBox>
             <TextBlock Grid.Column="2" Text="yo" VerticalAlignment="Center" Margin="5,0,0,0"></TextBlock>
             <TextBox Grid.Column="3" Margin="5,0,0,0" Height="Auto" VerticalAlignment="Center" HorizontalAlignment="Stretch" Text="{Binding baremo}"></TextBox>
             <TextBlock Grid.Column="4" Text="€" VerticalAlignment="Center" Margin="5,0,0,0"></TextBlock>
         </Grid>
    </DataTemplate>
 </ListBox.ItemTemplate>

当我将数据加载到 People ObservableCollection 时，一切正常并且显示完美。

我第一次选择一个人时，它起作用并在 VM 中设置属性值。

问题第二次出现 我选择了一个不同的“人”。该属性不会改变并且...每次我选择一个不同的属性时，它都会花费更长的时间(在 10 ó 20 之后它会更长)。 p>

这是我的 ViewModel 代码:

#region People
        public const string PeoplePropertyName = "People";

        private ObservableCollection<Player> _People;

        public ObservableCollection<Player> People
        {
            get
            {
                return _People;
            }

            set
            {
                _People = value;
                RaisePropertyChanged(People);
            }
        }
        #endregion

        #region Person
        public const string PersonPropertyName = "Person";

        private Player _Person;

        public Player Person
        {
            get
            {
                return _Person;
            }

            set
            {
                _Person = value;
                RaisePropertyChanged(PersonPropertyName);
            }
        }
        #endregion

我正在像这样加载人员列表:

void LoadPeople(GetPlayersEventArgs e)
{
     if (this.People == null) this.People = new ObservableCollection<Player>();

        foreach (Player Person in e.Result)
        {
            Player newPerson = new Player();
            ...
            this.People.Add(newPerson);
        }

        this.SetUnBusy();
}

我错过了什么吗？？提前致谢。

在我每次尝试选择另一个值时看到的@Ryan 问题之后，我得到很多:

A first chance exception of type 'System.InvalidCastException' occurred in Solution

Answer 1

根据您分享的 Person 的实现情况属性(property)不错。我会推荐一些东西。

按照vinod8812的建议，将绑定(bind)模式改为OneWay ，或将其删除为 OneWay是默认值:

<ListBox ItemsSource="{Binding People}" SelectedItem="{Binding Person, Mode=TwoWay}" >

更改填充 ObservableCollection<Player> 的顺序在你的 ViewModel 中:

public class ViewModel
{
    private readonly ObservableCollection<Player>();

    public ViewModel()
    {
        _People = new ObservableCollection<Player>();
    }

    public ObservableCollection<Player> People
    {
        get
        {
            return _People;
        }
    }
    /* rest of class */
}

最后，清除_People在填充它之前收集。否则，您可能只是在添加重复项:

void LoadPeople(GetPlayersEventArgs e)
{
    _People.Clear();

    foreach (Player Person in e.Result)
    {
        Player newPerson = new Player();
        ...
        this.People.Add(newPerson);
    }

    this.SetUnBusy();
}

你知道有什么是绑定(bind)到 INotifyPropertyChanged.PropertyChanged 的吗？您的 ViewModel 上的事件？从您分享的代码中，我们并不清楚到底是什么导致了应用程序变慢。