[英]WPF binding data to RowDetailsTemplate
我正在创建一个将显示调查问卷的程序。 问卷按类别(Cat 1、Cat 2 等)划分。 每个类别可以包含多个问题,每个问题可以有多个选择题答案。 我使用 DataGrid (objDatagrid) 和嵌套在 RowDetailsTemplate 中的另一个 DataGrid (objInnerDatagrid) 构建了此问卷。 我正在尝试对其进行设置,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不会折叠任何内容。 我通过将外部 DataGrid 设置为:RowDetailsVisibilityMode="Visible" 来实现这一点
不幸的是,由于我的代码,基于当前选择的问题,每个问题的答案现在都是相同的。 当我第一次设置它时,我没有使用 RowDetailsVisibilityMode="Visible"。 因此默认操作是折叠所有未选择的问题。 但正如我所说,这不是我的预期设计。
我很确定我的代码中的错误是在内部网格 (objInnerDataGrid) ItemsSource 绑定中。 但是不知道改成什么。
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; }
}
您对内部网格绑定的假设是正确的,因为您对当前选定的行有一个显式绑定,该行实际上跳出当前项目并将其绑定到所有行。
<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上下文的相对绑定,例如
<DataGrid x:Name="objInnerDatagrid"
ItemsSource="{Binding Answers}"
您可能必须明确指定DataContext
,如果是这样,请使用:
<DataGrid x:Name="objInnerDatagrid"
ItemsSource="{Binding DataContext.Answers}"
请记住,绑定最终是基于对象数据上下文的代码反射,在大多数情况下它是从父级继承的,因此在这些情况下,请考虑父级并相应地绑定。
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