Combobox和DisplayMemberBinding值

Question

我在线搜索过，但我无法找到问题的答案。可能是因为我不是100％熟悉XAML但是......

我希望能够通过代码设置组合框数据源。我做了什么。但是，此组合框选定值将更新以匹配列表视图中选择的值，并且在编辑组合框时，列表视图中的值也会更新。我认为这可以通过仅绑定来完成。我不想硬编码一些＆＃39;解决问题。因为我已经找到了解决方案。

XAML代码：

<ListView Name="ActionListView" ItemsSource="{Binding Actions, UpdateSourceTrigger=PropertyChanged}" SelectedItem="{Binding Path=FirstListViewSelectedItem, Mode=TwoWay}">
    <ListView.View>                
        <GridView>
            <GridViewColumn Header="Command" DisplayMemberBinding="{Binding Command}" />
        </GridView>
    </ListView.View>
</ListView>

<ComboBox IsEditable="True" Name="CommandCB" ItemsSource="{Binding Commands}" SelectedValue="{Binding Path=Command, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>

C＃CODE：

public partial class DetailsView : UserControl, INotifyPropertyChanged {

public event PropertyChangedEventHandler PropertyChanged;

private ObservableCollection<ActionObject> myActions;
public ObservableCollection<ActionObject> Actions
{
    get { return myActions; }
    set
    {
        if (myActions != value)
        {
            myActions = value;
            OnPropertyChanged("Actions");
        }
    }
}

private List<string> myCommands;
public List<string> Commands
{
    get { return myCommands; }
    set
    {
        if (myCommands != value)
        {
            myCommands = value;
            OnPropertyChanged("Commands");
        }
    }
}

private string myCommand;
public string Command
{
    get { return myCommand; }
    set
    {
        if (value != myCommand)
        {
            myCommand = value;
            OnPropertyChanged("Command");
        }
    }
}

protected void OnPropertyChanged(string name)
{
    PropertyChangedEventHandler handler = PropertyChanged;
    if (handler != null)
    {
        handler(this, new PropertyChangedEventArgs(name));
    }
}

public DetailsView()
{
    myCommands = GetCommandObjects().Select(x => x.Name).ToList();
    myActions = new ObservableCollection<ActionObject>();

    InitializeComponent();
    DataContext = this;
}

private List<CommandObject> GetCommandObjects()
{
    using (StreamReader r = new StreamReader("commands.json"))
    {
        return JsonConvert.DeserializeObject<List<CommandObject>>(r.ReadToEnd());
    }
}

private void MenuItem_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    if (ActionListView.SelectedIndex != -1)
    {
        if (ActionListView.SelectedItem == null)
            return;

        ActionObject _action = myActions.ElementAt(ActionListView.SelectedIndex);
        Command = _action.Command;
    }
}
}


public class ActionObject
{
    public string Command   { get; set; }
    public string Target    { get; set; }
    public string Value     { get; set; }
    public string Comment   { get; set; }
}

Answer 1

将List<string> Commands替换为ObservableCollection<string> Commands

此外，您不应该反复分配集合。从中移除和/或添加项目。

所以你的代码变成了这个

private ObservableCollection<ActionObject> myActions;
public ObservableCollection<ActionObject> Actions
{
    get 
    {
         if (myActions == null) 
             myActions = new ObservableCollection<ActionObject>();
         return myActions; 
    }
}

private ObservableCollection<string> myCommands;
public ObservableCollection<string> Commands
{
    get 
    {
        if (myCommands == null) 
            myCommands = new ObservableCollection<string>();
        return myCommands; 
    }
}

Answer 2

找到了解决方案。

一个：

ItemsSource="{Binding Commands}" SelectedValue="{Binding Path=Command, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"

答案：

ItemsSource="{Binding Commands}" SelectedValue="{Binding ElementName=ActionListView, Path=SelectedItem.Command, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"

我必须设置ElementName和Path以匹配Listview。