帶有IEnumerable集合的Item模板內的ComboBox系結

我有一個繼承自AvailableMovies集合的類MovieSystem 。

public class MovieSystem  : IEnumerable<AvailableMovies >, IEnumerable
{
    public AvailableMovies this[int i] { get; }
    public AvailableMovies this[TheatreLocation location] { get; }
    public AvailableMovies [] ReleasedMovies { get; }
 }

TheatreLocation 是一個列舉，其值如下

public enum TheatreLocation 
{
        Citycentre = 0,
        CityNorth = 1,
        CitySouth = 2,
        CityEast = 3,
        CityWest = 4,
}

AvailableMovies 集合具有以下屬性

public class AvailableMovies 
{
        public AvailableMovies ();
        public int Index { get; }
        public TheatreLocation Location { get; set; }
        public string TheatreID { get; set; }
        public double Ticketprice{ get; }
}

我的 Xaml 代碼如下所示

<ItemsControl ItemsSource="{Binding MovieSystem  }">            
                <ItemsControl.ItemTemplate>
                    <DataTemplate>
                            <ComboBox 
                                      ItemsSource="{Binding Path= ""What should I bind here? ""}"
                                      DisplayMemberPath="{Binding Path = ???}"
                                      SelectedIndex="{Binding Path =Location , Mode=TwoWay, Converter={StaticResource MovieSystemLocationConverter}}">
                            </ComboBox>
                            <ComboBox
                                      ItemsSource="{Binding Path = ???}"
                                      SelectedIndex="{Binding Path=TheatreID , Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
                                      DisplayMemberPath="{Binding Path= ??}">
                            </ComboBox>
                            <TextBox Grid.Column="3"
                                     Text="{Binding Path= Ticketprice, Mode =TwoWay,StringFormat=F3, NotifyOnValidationError=True}"/>
                                    
                    </DataTemplate>
                </ItemsControl.ItemTemplate>
</ItemsControl>

我有一個視圖模型，xaml datacontext 設定為此視圖模型。

internal class MovieSystemPanelViewModel
{
        ///tried this collection but not worked.
        public ObservableCollection<LocationViewModel> Locations { get; } = new ObservableCollection<LocationViewModel>();
   
        public MovieSystem MovieSystem { get; }
              
        public MovieSystemPanelViewModel() {}
}

現在我的問題是 ComboBox 應該顯示劇院 id 和由于系結問題而未顯示的位置。如果嘗試在 ComboBox itemsource 中系結該 Locations 可觀察集合，則它不允許，在專案模板內部，只有 AvailableMovies 屬性處于可系結條件。Ticketprice 已正確系結并顯示。

uj5u.com熱心網友回復：

這里的問題是，由于您正在系結Items.Control一個集合，因此該集合的子元素Items.Control將只能訪問該集合的屬性。因此，如果您想使用另一個集合，您需要使用它relative source來獲得datacontext級別訪問權限。而且由于它是enum正確顯示的，因此您需要使用擴展方法顯示字典值，并使用另一個Itemtemplate內部方法ComboBox來獲得正確的顯示。

internal class MovieSystemPanelViewModel
{
        ///Use  dictionary instead of observable collection
        public Dictionary<TheatreLocation , string> Locations { get; } = new Dictionary<TheatreLocation , string>();
   
        public MovieSystem MovieSystem { get; };
              
        public MovieSystemPanelViewModel() 
        {
            // Fill up data in dictionary
            foreach (Enum item in Enum.GetValues(typeof(TheatreLocation)))
            {
                Locations.Add((TheatreLocation)item, ((TheatreLocation)item).GetDisplayName());
            }
        }
}

在某處的專案中寫一個擴展方法，根據要求顯示成員。

public static string GetDisplayName(this TheatreLocation location)
{
            switch (location)
            {
                case TheatreLocation.CityCentre:
                    return "Center city location";

                case TheatreLocation.CityNorth :
                    return "Northern city location";

                case TheatreLocation.CitySouth :
                    return "Southern city location";

                case TheatreLocation.CityEast :
                    return "Eastern city location";

                case CameraLocation.CityWest :
                    return "Western city location";

                 default:
                    return "Unknown";
            }
}

現在系結xaml這些屬性和方法。

<ComboBox 
         ItemsSource="{Binding Path= DataContext.Locations, RelativeSource={RelativeSource AncestorType={x:Type UserControl}}}"
          SelectedIndex="{Binding Path =Location , Mode=TwoWay, Converter={StaticResource MovieSystemLocationConverter}}">
            <ComboBox.ItemTemplate>
                  <DataTemplate>
                             <TextBlock Text="{Binding Path=Value}" />
                   </DataTemplate>
              </ComboBox.ItemTemplate>
</ComboBox>

標籤：C＃ wpf 虚拟机 组合框 物品控制

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