使用 ComboBox 加载具有外键的 DataGrid 行

Question

我正在尝试将一系列行加载到包含其他表的外键的 DataGrid 中。在这种特定情况下，行有一个 TransactionTypeID（TransactionTypes 表的外键），我希望我的 ComboBox（ItemsSource 是 Transactions 表中的 DataView 类型）正确显示并允许修改。

<DataGridTemplateColumn Header="Transaction Types">
    <DataGridTemplateColumn.CellTemplate>
        <DataTemplate>
            <TextBlock Text="Need ComboBox SelectedText here!"></TextBlock>
        </DataTemplate>
    </DataGridTemplateColumn.CellTemplate>
    <DataGridTemplateColumn.CellEditingTemplate>
        <DataTemplate>
            <ComboBox ItemsSource="{Binding DataContext.TransactionTypes, RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}}"
                DisplayMemberPath="Description"
                SelectedValuePath="ID"
                SelectedItem="{Binding TransactionTypeID}"></ComboBox>
        </DataTemplate>
    </DataGridTemplateColumn.CellEditingTemplate>
</DataGridTemplateColumn>

ComboBox SelectedItem 似乎不起作用，我不知道如何填充 TextBlock 文本。

Answer 1

我的理解是，您要设置列的值并根据下拉列表中的特定选择显示交易类型描述。此示例显示在从编辑模板的下拉列表中选择值后绑定文本块中的文本。

XAML：

<Grid DataContext="{x:Static local:dc.Instance}">
    <Grid.Resources>
        <DataTemplate x:Key="DisplayTemplate" >
            <TextBlock Text="{Binding TransactionType.Description}"></TextBlock>
        </DataTemplate>
        <DataTemplate x:Key="EditTemplate">
            <ComboBox ItemsSource="{x:Static local:dc.TransactionTypes}"
                DisplayMemberPath="Description"
                SelectedItem="{Binding TransactionType}">
            </ComboBox>
        </DataTemplate>
    </Grid.Resources>
    <DataGrid Name="DG1" ItemsSource="{Binding Path=DGItems}" AutoGenerateColumns="False" >
        <DataGrid.Columns>
            <DataGridTemplateColumn Header="Transaction Type" 
                                    CellTemplate="{StaticResource DisplayTemplate}" 
                                    CellEditingTemplate="{StaticResource EditTemplate}" />
        </DataGrid.Columns>
    </DataGrid>
</Grid>

数据上下文类：

public class dc
{
    private static readonly dc _dc = new dc();
    public static dc Instance { get { return _dc;  } }


    public class TransactionTypeItem
    {
        public int ID { get; set; }
        public string Description { get; set; }
    }

    public static List<TransactionTypeItem> TransactionTypes
    {
        get
        {
            return new List<TransactionTypeItem>() { new TransactionTypeItem() { ID = 0, Description = "Zero" },
                                                    new TransactionTypeItem() { ID = 1, Description = "One" },
                                                    new TransactionTypeItem() { ID = 2, Description = "Two" } };
        }
    }

    public class DataItem
    {
        public TransactionTypeItem TransactionType { get; set; }
        public string OtherData { get; set; }
    }


    private List<DataItem> _items;

    public List<DataItem> DGItems
    {
        get
        {
            return _items;
        }
    }




    private dc()
    {
        _items = new List<DataItem>()
        {
            new DataItem() { OtherData = "Test0", TransactionType = TransactionTypes[0] },
            new DataItem() { OtherData = "Test1", TransactionType = TransactionTypes[1] },
            new DataItem() { OtherData = "Test2", TransactionType = TransactionTypes[2] },
        };
    }

}