尝试在 WPF 中设置子数据网格的项源时获取异常，例如"Items collection must be empty before using ItemsSource."

Question

我有一个datagrid和另一个数据杂志嵌套在父数据杂题内。我需要将Child DataGrid的项目资源设置为Parent DataContext的属性。我已经尝试使用reactracteRce将儿童物品库来获取父datacontext。

XAML代码

<DataGrid Grid.Row ="1" x:Name="Grid1" ItemsSource="{Binding Path=md,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" AutoGenerateColumns="False">
    <DataGrid.Columns>
      <DataGridTextColumn Header="Categogy" Width="100"  Binding="{Binding Path =CateName,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
      <DataGridTemplateColumn Header="Characterictics" Width="300">
           <DataGridTemplateColumn.CellTemplate>
             <DataTemplate>
               <DataGrid ItemsSource="{Binding DataContext.list, RelativeSource={RelativeSource AncestorType=DataGrid}}">
                 <DataGridTextColumn Binding="{Binding DataContext.list.Name, RelativeSource={RelativeSource AncestorType=DataGrid}}" />
               </DataGrid>
             </DataTemplate>
           </DataGridTemplateColumn.CellTemplate>
      </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>

ViewModel

Model m = new Model();
m.CateName = "CategoryName";
m.list.Add(new Characteristics() { Name="XX", Value="00"});
m.list.Add(new Characteristics() { Name = "XX", Value = "00" });
m.list.Add(new Characteristics() { Name = "XX", Value = "00" });
md.Add(m);
Model m1 = new Model();
m1.CateName = "CategoryName1";
m1.list.Add(new Characteristics() { Name = "XX", Value = "00" });
m1.list.Add(new Characteristics() { Name = "XX", Value = "00" });
m1.list.Add(new Characteristics() { Name = "XX", Value = "00" });
md.Add(m1);
list = new ObservableCollection<Characteristics>();
list.Add(new Characteristics() { Name = "XX", Value = "00" });
list.Add(new Characteristics() { Name = "XX", Value = "00" });

特征类具有属性名称和模型。

现在，我得到的例外，例如"物品收集必须在使用项目库之前为空"。

我不确定我在哪里做错了吗？有人可以帮助我正确地绑定儿童datagrid interce吗？

Answer 1

对于嵌套的datagrid放置DataGridTextColumn中的 <DataGrid.Columns> tag

<DataGrid ItemsSource="{Binding list}">
  <DataGrid.Columns>
    <DataGridTextColumn Binding="{Binding Name}" />
  </DataGrid.Columns>
</DataGrid>

否则，datagridtextcolumn被解释为项目，并导致ategrysource

的错误

，还修复了绑定，他们不需要使用parent dataContext

Answer 2

我认为您可以尝试此

 <DataGrid Grid.Row ="1" x:Name="Grid1" ItemsSource="{Binding Path=md,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" AutoGenerateColumns="False">
            <DataGrid.Columns>
                <DataGridTextColumn Header="Categogy" Width="100"  Binding="{Binding Path =CateName,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
                <DataGridTemplateColumn Header="Characterictics" Width="600">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <DataGrid   AutoGenerateColumns="False" Height="100" ItemsSource="{Binding list}">
                                <DataGrid.Columns>
                                    <DataGridTextColumn Header="Name" Binding="{Binding Name}" />
                                </DataGrid.Columns>
                            </DataGrid>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>
            </DataGrid.Columns>
        </DataGrid>

编辑：如果您希望从窗口的数据台上使用列表请更改为

的嵌套datarid

 <DataGrid   AutoGenerateColumns="False" Height="100" ItemsSource="{Binding list,RelativeSource={RelativeSource AncestorType=Window}}">
                                <DataGrid.Columns>
                                    <DataGridTextColumn Header="Name" Binding="{Binding Name}" />
                                </DataGrid.Columns>
                            </DataGrid>

ViewModel：

  public partial class MainWindow : Window
    {
        private ObservableCollection<Model> _md = new ObservableCollection<Model>();
        public ObservableCollection<Model> md
        {
            get { return _md; }
            set { _md = value; }
        }
        private ObservableCollection<Characteristics> _list;
        public ObservableCollection<Characteristics> list
        {
            get { return _list; }
            set { _list = value; }
        }
        public MainWindow()
        {
            InitializeComponent();
            this.DataContext = this;
            Model m = new Model();
            m.CateName = "CategoryName";
            m.list.Add(new Characteristics() { Name = "test Name", Value = "00" });
            m.list.Add(new Characteristics() { Name = "TEst name1", Value = "00" });
            m.list.Add(new Characteristics() { Name = "XX", Value = "00" });
            md.Add(m);
            Model m1 = new Model();
            m1.CateName = "CategoryName1";
            m1.list.Add(new Characteristics() { Name = "XX", Value = "00" });
            m1.list.Add(new Characteristics() { Name = "XX", Value = "00" });
            m1.list.Add(new Characteristics() { Name = "XX", Value = "00" });
            md.Add(m1);
            list = new ObservableCollection<Characteristics>();
            list.Add(new Characteristics() { Name = "vali", Value = "00" });
            list.Add(new Characteristics() { Name = "XX", Value = "00" });
        }      
    }
    public class Model
    {
        private string cateName;
        public string CateName
        {
            get { return cateName; }
            set { cateName = value; }
        }
        private List<Characteristics> _list = new List<Characteristics>();
        public List<Characteristics> list
        {
            get { return _list; }
            set { _list = value; }
        }
    }
    public class Characteristics
    {
        private string name;
        public string Name
        {
            get { return name; }
            set { name = value; }
        }
        private string value;
        public string Value
        {
            get { return this.value; }
            set { this.value = value; }
        }
    }