WPF将数据绑定到RowDetailsTemplate

Question

我正在创建一个显示问卷的程序。问卷按类别划分(猫1、猫2等)。每个类别可以包含许多问题，每个问题可以有多个选择题答案。我使用一个DataGrid (objDatagrid)和一个嵌套在RowDetailsTemplate中的另一个DataGrid (objInnerDatagrid)构建了这个调查问卷。我试图设置它，以便在程序加载时显示所有问题和所有答案。这意味着默认情况下什么都不会崩溃。为此，我将外部DataGrid设置为:RowDetailsVisibilityMode=“可见”。

不幸的是，由于我的代码，每个问题的答案现在都是相同的，无论哪一个问题是当前的选择。当我第一次设置它时，我没有使用RowDetailsVisibilityMode=“可见”。因此，默认操作是折叠所有未选中的问题。但正如我所说，这不是我想要的设计。

我很确定我的代码中的错误在内部网格(objInnerDataGrid) ItemsSource绑定中。但我不知道该把它改成什么。

XAML：

<Grid>
    <StackPanel>
        <TextBox Controls:TextBoxHelper.Watermark="enter search term" Name="TxtFilter" Margin="10" TextChanged="TxtFilter_TextChanged" Height="25" MinWidth="250" HorizontalAlignment="Stretch"/>
        <DataGrid x:Name="objDatagrid" ItemsSource="{Binding DataView}" IsReadOnly="True" CanUserAddRows="False" CanUserDeleteRows="False" Loaded="objDatagrid_Loaded" AutoGenerateColumns="False"
              HeadersVisibility="None" ScrollViewer.VerticalScrollBarVisibility="Auto" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" RowDetailsVisibilityMode="Visible">
            <DataGrid.RowDetailsTemplate>
                <DataTemplate>
                    <DataGrid x:Name="objInnerDatagrid" ItemsSource="{Binding ElementName=objDatagrid, Path=SelectedItem.Answers}" CanUserAddRows="False" IsReadOnly="True" CanUserDeleteRows="False"
                              HeadersVisibility="None" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
                        <DataGrid.Columns>
                            <DataGridCheckBoxColumn ElementStyle="{DynamicResource MetroDataGridCheckBox}" 
                                                    EditingElementStyle="{DynamicResource MetroDataGridCheckBox}" 
                                                    Binding="{Binding Answers.AnswerText}"/>
                        </DataGrid.Columns>
                    </DataGrid>
                </DataTemplate>
            </DataGrid.RowDetailsTemplate>

            <DataGrid.Columns>
                <DataGridTextColumn Width="Auto" Binding="{Binding QuestionText}" IsReadOnly="True"/>
            </DataGrid.Columns>
            <DataGrid.GroupStyle>
                <GroupStyle>
                    <GroupStyle.HeaderTemplate>
                        <DataTemplate>
                            <StackPanel>
                                <TextBlock Text="{Binding Path=Name}" />
                            </StackPanel>
                        </DataTemplate>
                    </GroupStyle.HeaderTemplate>
                    <GroupStyle.ContainerStyle>
                        <Style TargetType="{x:Type GroupItem}">
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="{x:Type GroupItem}">
                                        <Expander Margin="15 0 15 0" Header="{Binding Path=Name}" IsExpanded="True" VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
                                            <ItemsPresenter VerticalAlignment="Stretch" HorizontalAlignment="Stretch"/>
                                        </Expander>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </GroupStyle.ContainerStyle>
                </GroupStyle>
            </DataGrid.GroupStyle>
        </DataGrid>
    </StackPanel>
</Grid>

​

C#：

public partial class DataEmbed : UserControl
{
    DataTable dt = new DataTable();

    public DataEmbed()
    {
        InitializeComponent();

        DataContext = this;

        _dataView = new ListCollectionView(new ObservableCollection<Question>(Populate()));
        _dataView.GroupDescriptions.Add(new PropertyGroupDescription("CategoryString"));

        CollectionView cv = (CollectionView)CollectionViewSource.GetDefaultView(DataView);
        cv.Filter = CustomFilter;
    }
    private List<Question> Populate()
    {
        return new List<Question>()
        {
            new Question()
            {
                CategoryString = "Cat 1",
                QuestionText = "Question 1",
                Answers = new ObservableCollection<Answer>
                {
                    new Answer {AnswerText = "Answer 1"},
                    new Answer {AnswerText = "Answer 2"},
                    new Answer {AnswerText = "Answer 3"},
                    new Answer {AnswerText = "Answer 4"}
                }
            },

            new Question()
            {
                CategoryString = "Cat 1",
                QuestionText = "Question 2",
                Answers = new ObservableCollection<Answer>
                {
                    new Answer {AnswerText = "Answer 5"},
                    new Answer {AnswerText = "Answer 6"},
                    new Answer {AnswerText = "Answer 7"},
                    new Answer {AnswerText = "Answer 8"},
                }
            },

            new Question()
            {
                CategoryString = "Cat 2",
                QuestionText = "Question 1",
                Answers = new ObservableCollection<Answer>
                {
                    new Answer {AnswerText = "Answer 9"},
                    new Answer {AnswerText = "Answer 10"},
                    new Answer {AnswerText = "Answer 11"},
                    new Answer {AnswerText = "Answer 12"},
                }
            }

        };
    }

    private ListCollectionView _dataView;
    public ListCollectionView DataView
    {
        get { return _dataView; }
        set { _dataView = value; }
    }

    private void objDatagrid_Loaded(object sender, RoutedEventArgs e)
    {

    }
}

课程：

public class Question
    {
        public string CategoryString { get; set; }
        public bool IsCategoryExpanded { get; set; }
        public string QuestionText { get; set; }
        public ObservableCollection<Answer> Answers { get; set; }
    }

    public class Answer
    {
        public string AnswerText { get; set; }
    }

Answer 1

关于内部网格绑定的假设是正确的，因为您有一个到当前选定的行的显式绑定，它实际上从当前项中跳出，并将其绑定到所有行的。

<DataGrid x:Name="objInnerDatagrid" 
           ItemsSource="{Binding ElementName=objDatagrid, Path=SelectedItem.Answers}" 

对于所有行，您想要的绑定是基于当前项的父数据文本(如

<DataGrid x:Name="objInnerDatagrid" 
           ItemsSource="{Binding Answers}" 

您可能必须显式地指定DataContext，如果是这样的话，请使用以下命令：

<DataGrid x:Name="objInnerDatagrid" 
           ItemsSource="{Binding DataContext.Answers}" 

记住，绑定最终是基于对象数据文本的代码反射，在大多数情况下，这些对象是从父对象继承的，因此在这些情况下，要考虑父对象并相应地绑定。