c# - 两个表的 Wpf DatagridComboBoxColumn 绑定(bind)？

Question

我必须上课 Books and Publishing Houses:

public partial class Books
{
    public Books()
    {
        this.Authors = new ObservableCollection<Authors>();
    }

    public int bID { get; set; }
    public string Title { get; set; }
    public int phID { get; set; }
    public Nullable<short> PubYear { get; set; }
    public Nullable<short> Edition { get; set; }

    public virtual PublishingHouse PublishingHouse { get; set; }
    public virtual ObservableCollection<Authors> Authors { get; set; }
}
public partial class PublishingHouse
{
    public PublishingHouse()
    {
        this.Books = new ObservableCollection<Books>();
    }

    public int phID { get; set; }
    public string Title { get; set; }
    public string City { get; set; }    

    public virtual ObservableCollection<Books> Books { get; set; }
}

所以我有 Datagrid，它显示了我所有的书:

<Window.Resources>
    <CollectionViewSource x:Key="booksViewSource" d:DesignSource="{d:DesignInstance {x:Type local:Books}, CreateList=True}"/>
    <CollectionViewSource x:Key="booksAuthorsViewSource" Source="{Binding Authors, Source={StaticResource booksViewSource}}"/>
    <CollectionViewSource x:Key="authorsViewSource" d:DesignSource="{d:DesignInstance {x:Type local:Authors}, CreateList=True}"/>
    <CollectionViewSource x:Key="publishingHouseViewSource" d:DesignSource="{d:DesignInstance {x:Type local:PublishingHouse}, CreateList=True}"/>
</Window.Resources>
<Grid DataContext="{StaticResource booksViewSource}" Margin="0,0,2,0">
    <DataGrid ItemsSource="{Binding}">
        <DataGrid.Columns>
            <DataGridTextColumn Header="b ID" Binding="{Binding bID}"/>
            <DataGridTextColumn Header="Title" Binding="{Binding Title}"/>
            <DataGridTextColumn Header="#" Binding="{Binding Edition}"/>
            <DataGridTextColumn Header="Year" Binding="{Binding PubYear}"/>
            <DataGridComboBoxColumn x:Name="phIDComboBoxColumn" SelectedItemBinding="{Binding phID}" />
        </DataGrid.Columns>
    </DataGrid>

我想要的是将我的 phIDComboBoxColumn 的默认值设置为取自一本书，但是当我想编辑它时，我想查看 phId 的列表 所有可用的 PublishingHouses。我必须以某种方式为两个数据源绑定(bind)“DataGridComboBoxColumn”吗？

Answer 1

您的 Book 类应该有一个 Property，其中包含所有可用 PublishingHouses 的 phId 列表，如下所示:

public ObservableCollection<int> PhIdList {get; set;}

然后你的 DataGridComboBoxColumn 改变如下:

<DataGridComboBoxColumn Header="PhIDs" SelectedItemBinding="{Binding phID}">
    <DataGridComboBoxColumn.ElementStyle>
        <Style TargetType="ComboBox">
            <Setter Property="ItemsSource" Value="{Binding PhIdList}"/>
            <Setter Property="IsReadOnly" Value="True"/>
        </Style>
    </DataGridComboBoxColumn.ElementStyle>
    <DataGridComboBoxColumn.EditingElementStyle>
        <Style TargetType="ComboBox">
            <Setter Property="ItemsSource" Value="{Binding PhIdList}"/>
        </Style>
    </DataGridComboBoxColumn.EditingElementStyle>
</DataGridComboBoxColumn>

编辑

If i do so, every object of Book will contain identical collections of avaliable PublishingHouses. That's very unefficient by memory. Is it any other solution?

为了防止数据冗余，您可以在父类 中定义PhIdList(例如，如果您使用的是 mvvm，则为书单容器 View 模型)并获取 ComboBox 数据如下:

            <DataGridComboBoxColumn 
                SelectedItemBinding="{Binding phID}" DisplayMemberPath="" >
                <DataGridComboBoxColumn.ElementStyle>
                    <Style TargetType="{x:Type ComboBox}">
                        <Setter Property="ItemsSource" Value="{Binding Path=DataContext.BooksContainerVM.PhIdList, RelativeSource={RelativeSource AncestorType={x:Type Window}}}" />
                    </Style>
                </DataGridComboBoxColumn.ElementStyle>
                <DataGridComboBoxColumn.EditingElementStyle>
                    <Style TargetType="{x:Type ComboBox}">
                        <Setter Property="ItemsSource" Value="{Binding Path=DataContext.BooksContainerVM.PhIdList, RelativeSource={RelativeSource AncestorType={x:Type Window}}}" />
                    </Style>
                </DataGridComboBoxColumn.EditingElementStyle>
            </DataGridComboBoxColumn>