ComboBox SelectedItem结合

Question

我在我的ComboBox视图中有一个

<ComboBox Name="comboBox1" ItemsSource="{Binding MandantList}" SelectedItem="{Binding CurrentMandant, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}">
    <ComboBox.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding Firma}"/>
        </DataTemplate>
    </ComboBox.ItemTemplate>
</ComboBox>

这是我的型号

public class MandantListItem : INotifyPropertyChanged
{
    public MandantListItem() { }

    string _Firma;
    bool _IsChecked;

    public string Firma
    {
        get { return _Firma; }
        set { _Firma = value; }
    }
    public bool IsChecked
    {
        get
        {
            return _IsChecked;
        }
        set
        {
            _IsChecked = value;
            OnPropertyChanged(nameof(IsChecked));
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

这是我的ViewModel

public class MaViewModel : INotifyPropertyChanged
{
    public ObservableCollection<MandantListItem> MandantList { get { return _MandantList; } }
    public ObservableCollection<MandantListItem> _MandantList = new ObservableCollection<MandantListItem>();

    private MandantListItem _CurrentMandant;
    public MandantListItem CurrentMandant
    {
        get { return _CurrentMandant; }
        set
        {
            if (value != _CurrentMandant)
            {
                _CurrentMandant = value;
                OnPropertyChanged("CurrentMandant");
            }
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

如何填充ComboBox：

public zTiredV2.ViewModel.MaViewModel MAList = new zTiredV2.ViewModel.MaViewModel();
this.comboBox1.ItemsSource = MAList.MandantList;
MAList.MandantList.Add(new zTiredV2.Model.MandantListItem { Firma = "A", Homepage = "a.com", IsChecked = false });
MAList.MandantList.Add(new zTiredV2.Model.MandantListItem { Firma = "B", Homepage = "b.com", IsChecked = false });

但我的物品没有更新..。也尝试过通过IsChecked，但也没有成功.当我遍历MAList时，IsChecked总是假的。如何将TextBlock绑定到所选的Firma？

很难处理MVVM，但我喜欢它。

Answer 1

您应该将DataContext的ComboBox设置为视图模型的实例。否则，绑定将无法工作：

this.comboBox1.DataContext = MAList;

还请注意，属性的_MandantList后备字段不应该是公共的。事实上，你根本不需要它：

public ObservableCollection<MandantListItem> MandantList { get; } = new ObservableCollection<MandantListItem>();

设置DataContext会导致在选择ComboBox中的项时设置CurrentMandant属性。不过，它不会设置IsChecked属性。