ItemsControl 上的 WPF MVVM 单选按钮

Question

我之前已经将枚举绑定(bind)到单选按钮，并且我大致了解它是如何工作的。我使用了这个问题的替代实现:How to bind RadioButtons to an enum?

我想生成一个自定义类型的运行时枚举集，而不是枚举，并将它们呈现为一组单选按钮。我得到了一个 View ，它使用 ListView 处理运行时枚举集。 , 绑定(bind)到 ItemsSource和 SelectedItem属性，所以我的ViewModel已正确连接。现在我正在尝试从 ListView 切换到 ItemsControl带有单选按钮。

据我所知，这是:

<Window.Resources>
    <vm:InstanceToBooleanConverter x:Key="InstanceToBooleanConverter" />
</Window.Resources>

<!-- ... -->

<ItemsControl ItemsSource="{Binding ItemSelections}">
    <ItemsControl.ItemTemplate>
        <DataTemplate DataType="{x:Type vm:ISomeType}">
            <RadioButton Content="{Binding Name}"
                         IsChecked="{Binding Path=SelectedItem, Converter={StaticResource InstanceToBooleanConverter}, ConverterParameter={Binding}}"
                         Grid.Column="0" />
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

InstanceToBooleanConverter与 EnumToBooleanConverter 具有相同的实现从另一个问题。这似乎是正确的，因为它似乎只是调用了 Equals方法:

public class InstanceToBooleanConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return value.Equals(parameter);
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return value.Equals(true) ? parameter : Binding.DoNothing;
    }
}

我现在遇到的问题是我无法弄清楚如何将运行时值作为 ConverterParameter 发送。 .当我尝试(使用上面的代码)时，我收到此错误:

A 'Binding' cannot be set on the 'ConverterParameter' property of type 'Binding'. A 'Binding' can only be set on a DependencyProperty of a DependencyObject.

有没有办法绑定(bind)到项目实例，并将其传递给 IValueConverter ?

Answer 1

现在我知道 x:Shared (感谢您的 other question )，我放弃我之前的回答并说 MultiBinding毕竟是要走的路。

XAML:

<StackPanel>
    <TextBlock Text="{Binding SelectedChoice}" />

    <ItemsControl ItemsSource="{Binding Choices}">
        <ItemsControl.Resources>
            <local:MyConverter x:Key="myConverter" x:Shared="false" />
        </ItemsControl.Resources>
        <ItemsControl.ItemTemplate>
            <DataTemplate>
                <RadioButton>
                    <RadioButton.IsChecked>
                        <MultiBinding Converter="{StaticResource myConverter}" >
                            <Binding Path="DataContext.SelectedChoice" RelativeSource="{RelativeSource AncestorType=UserControl}" />
                            <Binding Path="DataContext" RelativeSource="{RelativeSource Mode=Self}" />
                        </MultiBinding>
                    </RadioButton.IsChecked>
                    <TextBlock Text="{Binding}" />
                </RadioButton>
            </DataTemplate>
        </ItemsControl.ItemTemplate>
    </ItemsControl>
</StackPanel>

View 模型:

class Viewmodel : INPC
{
    public Viewmodel()
    {
        Choices = new List<string>() { "one", "two", "three" };
        SelectedChoice = Choices[0];
    }

    public List<string> Choices { get; set; }

    string selectedChoice;
    public string SelectedChoice
    {
        get { return selectedChoice; }
        set
        {
            if (selectedChoice != value)
            {
                selectedChoice = value;
                OnPropertyChanged("SelectedChoice");
            }
        }
    }
}

转换器:

public class MyConverter : IMultiValueConverter
{
    object selectedValue;
    object myValue;

    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        selectedValue = values[0];
        myValue = values[1];

        return selectedValue == myValue;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
    {
        if ((bool)value)
        {
            return new object[] { myValue, Binding.DoNothing };
        }
        else
        {
            return new object[] { Binding.DoNothing, Binding.DoNothing };
        }

    }
}