使用ViewModel的WPF嵌套ListBox数据绑定

时间:2009-09-17 04:40:19

标签: wpf data-binding listbox hierarchical-data

这是一个很长的问题。我正在添加代码,以便您可以看到我想要做的事情。如果有什么不清楚,请告诉我

我试图在multiselct模式下从嵌套列表框中获取所选项目。这是代码(删除了许多不需要的东西)

public class Item
{
    public string Name { get; set; }

    public IList<Item> SubItems { get; set; } // 

    public bool IsSelected { get; set; }
}
//Chicken Fried Chicken 
//A hearty boneless chicken breast, lightly breaded in our special seasonings and 
//golden fried. Served with garlic mashed potatoes, country gravy and seasonal vegetables
// from Applebees

//Item - Chicken Fried Chicken 
//SubItem- mashed potatoes
//SubItem- country gravy
//SubItem- seasonal vegetables
//SubItem- Fries
//SubItem- Sauted vegetables
//SubItem- House Salad

public class ItemViewModel : INotifyPropertyChanged, IItemViewModel
{


    ObservableCollection<Item> selectedData = new ObservableCollection<Item>();

    private ObservableCollection<Item> todaysItems;
    public ObservableCollection<Item> TodaysItems
    {
        get { return todaysItems; }
        private set
        {
            if (todaysItems != value)
            {
                todaysItems = value;
                PropertyChanged(this, new PropertyChangedEventArgs("todaysItems"));
            }
        }
    }



    public ItemViewModel(IItemView itemView)
    {
        this.View = itemView;
        this.View.Model = this;

        List<Item> items = service.GetAllTestItems();
        TodaysItems = new ObservableCollection<Item>(items);

        selectedData.CollectionChanged += (sender, e) => UpdateSummary();
    }



    #region INotifyPropertyChanged Members

    public event PropertyChangedEventHandler PropertyChanged = delegate { };
    private void NotifyPropertyChanged(string propertyName)
    {
        var handler = this.PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
    #endregion


    // How to get Selected Items from ListBox

    public ObservableCollection<Item> SelectedData
    {
        get { return selectedData; }
        set
        {
            selectedData = value;
        }
    }


    private void UpdateSummary()
    {
        // here I can get selected data , I can find which Item is selected and then update its SubItems IsSelected (CLR) Property
        // but something is not right here
    }
}

XAML

<UserControl x:Class="ItemView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:prism="clr-namespace:Microsoft.Practices.Composite.Presentation.Commands;assembly=Microsoft.Practices.Composite.Presentation"
             xmlns:ZCom="clr-namespace:MyProj.Infrastructure;assembly=Infrastructure">

    <Grid  >
        <ListBox ItemsSource="{Binding TodaysItems}">
            <ListBox.ItemTemplate>
                <DataTemplate >
                    <Border BorderThickness="1,1,1,1" CornerRadius="2,2,2,2" BorderBrush="Black">
                        <Grid   MinHeight="50" Width="150" Height="Auto" Margin="0,0,0,0">
                            <Grid.RowDefinitions>
                                <RowDefinition />
                                <RowDefinition/>
                                <RowDefinition />
                            </Grid.RowDefinitions>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="150"/>
                                <ColumnDefinition Width="0"/>
                            </Grid.ColumnDefinitions>
                            <TextBlock Margin="4,4,2,2" Grid.Row="0"  Width="Auto" TextWrapping="Wrap" Text="{Binding Path=Name}"  />
                            <Grid Grid.Row="2" Grid.Column="0" Grid.ColumnSpan="2" >
                                <Grid.Style>
                                    <Style>
                                        <Style.Triggers>
                                            <DataTrigger Binding="{Binding Path=IsSelected, RelativeSource=
                                                                    {RelativeSource Mode=FindAncestor,AncestorType={x:Type ListBoxItem}}
                                            }" Value="false">
                                                <Setter Property="Grid.Visibility" Value="Collapsed"/>
                                            </DataTrigger>
                                        </Style.Triggers>
                                    </Style>
                                </Grid.Style>
                                <Grid.RowDefinitions>
                                    <RowDefinition Height="35"/>
                                    <RowDefinition Height="*"/>
                                </Grid.RowDefinitions>
                                <TextBlock Margin="2,4,2,2"  Grid.Row="0" Width="Auto" FontSize="10" FontStyle="Italic"  TextWrapping="Wrap"  Text="{Binding Path=Note}"/>

                                <ListBox Style="{DynamicResource MyStyle}" Grid.Row="1"  ItemsSource="{Binding Path=Modifiers}"  SelectionMode="Multiple"
                                         ZCom:ListBoxHelper.SelectedItems="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.SelectedData}">
                                    <ListBox.ItemTemplate>
                                        <DataTemplate >
                                            <TextBlock Margin="2,2,2,2"  TextWrapping="Wrap" Text="{Binding Path=Name}"  />
                                        </DataTemplate>

                                    </ListBox.ItemTemplate>
                                </ListBox>
                            </Grid>

                        </Grid>
                    </Border>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</UserControl>

我正在使用ListBoxHelper(在Infrastructure中) http://marlongrech.wordpress.com/2009/06/02/sync-multi-select-listbox-with-viewmodel/

我使用Item和SubItems获取视图。

1)从嵌套ListBox

设置SubItems的IsSelected属性的更好方法是什么

我将添加一个命令,一旦双击就将所选项存储到数据库。 SubItems将根据其IsSelected值存储为子记录。

2)有没有办法使c#class的SubItems属性可观察。我不希望通过向对象添加Observable来进行更改,因为它将在另一个程序集中,并且可能被其他应用程序使用。

编辑1: 找到了一些有用的问题

  

WPF Databinding to composite class patterns

但为此,我将不得不继承INotifyPropertyChanged。

编辑2: 让我看看我是否可以更好地解释 - ListBox1是单选模式和父母&amp; ListBox 2是多选的。 ListBox1被绑定(项目源)到返回observablecollection的属性。 ListBox2绑定到Item Class(Item.SubItems)中的Property,返回IList。 Item Class具有IsSelected属性。我希望能够选择子项,这些子项应该将subItems的IsSelected属性设置为true。知道Item Class中没有INotifyPropertyChanged继承,我怎么能实现这一点。我假设除非子项目属于某些可观察的集合,否则任何更改都不会通知回源。使用selectedData属性我可以通过查找父项来更新子项,但是为了更新视图,我将需要firePropertChanged用于涉及所有项和子项的“项目”。我希望只有子项更改才能通过绑定机制进行通知。对不起,如果我还不清楚。

编辑3:

我猜是没有办法在Item类上实现INotifyPropertyChanged。另一种方法是实现一个viewmodel,它非常特定于视图需求,但这会增加很多代码。

1 个答案:

答案 0 :(得分:0)

这有点令人困惑,你的总体目标是什么。

如果您只是尝试从嵌套的ListBox中获取所选项目,您是否尝试过给ListBox x:Name并通过UserControl(ItemView)类中的属性公开SelectedItems?

public IList SelectedItems
{
  get { return nestedListBox.SelectedItems; }
}