使用绑定 Avalonia 的条件数据模板选择

问题描述

我是 Avalonia 的新手，我需要为我的一个项目生成问题和答案列表。到目前为止，我已经根据需要生成了问题和答案。 XAML 代码

                <ItemsControl Items="{Binding Questions}">
                <ItemsControl.ItemTemplate>
                    <DataTemplate>
                        <StackPanel>
                            <TextBlock
                                Classes="header"
                                Text="{Binding QuestionDescription}"
                                textwrapping="Wrap" />
                            <ItemsControl Items="{Binding Answers}">
                                <ItemsControl.ItemTemplate>
                                    <DataTemplate>
                                        <CheckBox x:Name="{Binding AId}" Content="{Binding Answer}" />
                                    </DataTemplate>
                                </ItemsControl.ItemTemplate>
                            </ItemsControl>
                        </StackPanel>
                    </DataTemplate>
                </ItemsControl.ItemTemplate>
            </ItemsControl>

我现在想要的是根据我从 AnswerType 列表中获得的 Questions 值创建不同类型的回答选项（单选按钮或复选框）。这是我的问题模型

public class Question
{
    public string QId { get; set; }
    public string QuestionDescription { get; set; }
    public List<Answers> Answers { get; set; }
    public string AnswerType { get; set; }
}

public class Answers
{
    public string AId { get; set; }
    public string Answer { get; set; }
}

样本数据

  {
    "QId": "Q1","QuectionDescription": "Quection01","Answers": [
      {
        "AId": "Q1A1","Answer": "Yes"
      },{
        "AId": "Q1A2","Answer": "No"
      }
    ],"AnswerType": "RadioButton"
  },{
    "QId": "Q2","QuectionDescription": "Quection02","Answers": [
      {
        "AId": "Q2A1","Answer": "Football"
      },{
        "AId": "Q2A2","Answer": "Baseball"
      }
    ],"AnswerType": "CheckBox"
  }

解决方法

public class TemplateDictionaryConverter : Dictionary<string,IDataTemplate>,IValueConverter
{
    public object Convert(object value,Type targetType,object parameter,CultureInfo culture)
    {
        if (value is string s)
            return this[s];
        return null;
    }

    public object ConvertBack(object value,CultureInfo culture) 
        => throw new NotSupportedException();
}

<ItemsControl Items="{Binding Answers}">
    <ItemsControl.ItemTemplate>
        <Binding
            Path="AnswerType">
            <Binding.Converter>
                <example:TemplateDictionaryConverter>
                    <DataTemplate x:Key="CheckBox">
                        <CheckBox Content="{Binding Answer}" />
                    </DataTemplate>
                    <DataTemplate x:Key="RadioButton">
                        <RadioButton Content="{Binding Answer}" />
                    </DataTemplate>
                </example:TemplateDictionaryConverter>
            </Binding.Converter>
        </Binding>
    </ItemsControl.ItemTemplate>
</ItemsControl>