获取组中所选RadioButton的索引

Question

我有对RadioButton rb1的引用。
如何获取rb1组中所选RadioButton的索引？
我已经搜索了一段时间，但没有成功。

任何帮助将不胜感激

Answer 1

对您的问题的简短回答是，您不会。 您应该做的是将RadioButton.IsChecked绑定到视图模型的某些bool属性。 您可以通过实现IValueConverter视图模型的int属性来实现类似组索引的功能：

查看模型属性：

private int _groupIndex = 1;

public int GroupIndex
{
   get { return _groupIndex; }
   set
   {
       if (_groupIndex == value) return;
       _groupIndex = value;
       OnPropertyChanged("GroupIndex");
   }
}

转换器：

public class IndexBooleanConverter : IValueConverter
{
  public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
  {
      if (value == null || parameter == null)
          return false;
      else
          return (int)value == System.Convert.ToInt32(parameter);
  }

  public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
  {
      if (value == null || parameter == null)
          return null;
      else if ((bool)value)
          return System.Convert.ToInt32(parameter);
      else
          return DependencyProperty.UnsetValue;
  }
}   

然后像这样绑定它：

<StackPanel Orientation="Horizontal">
   <StackPanel.Resources>
       <local:IndexBooleanConverter x:Key="IndexBooleanConverter"/>
   </StackPanel.Resources>
   <RadioButton Content="Option1" IsChecked="{Binding Path=GroupIndex, Converter={StaticResource IndexBooleanConverter}, ConverterParameter=1}"/>
   <RadioButton Content="Option2" IsChecked="{Binding Path=GroupIndex, Converter={StaticResource IndexBooleanConverter}, ConverterParameter=2}"/>
   <RadioButton Content="Option3" IsChecked="{Binding Path=GroupIndex, Converter={StaticResource IndexBooleanConverter}, ConverterParameter=3}"/>
</StackPanel>

在这种情况下，取决于选中哪个RadioButton ，视图模型属性GroupIndex将具有值1、2或3

Answer 2

如果您到了这一步，则说明您的设计可能存在问题，应重新考虑。

话虽如此，您可以遍历视觉树并找到它，如下所示：

        /// Returns the first GroupBox ancester            
        public DependencyObject  FindAncestor(DependencyObject current)

        {
            current = VisualTreeHelper.GetParent(current);

            while (current != null)
            {
                if (current is GroupBox)
                {
                    return (T)current;
                }
                current = VisualTreeHelper.GetParent(current);
            };
            return null;
        }

然后遍历孩子并找到选中的单选按钮

    public RadioButton FindChild<T>(DependencyObject parent)       
    {
        // Confirm parent and childName are valid.
        if (parent == null) return null;

        RadioButton foundChild = null;

        int childrenCount = VisualTreeHelper.GetChildrenCount(parent);
        for (int i = 0; i < childrenCount; i++)
        {
            var child = VisualTreeHelper.GetChild(parent, i);
            // If the child is not of the request child type child
            var childType = child as radioButton;
            if (childType == null)
            {
                // recursively drill down the tree
                foundChild = FindChild(child);

                // If the child is found, break so we do not overwrite the found child.
                if (foundChild != null) return foundChild ;
            }
            else if (childName.IsChecked == true)
            {
               return foundChild;  
            }
        }

        return null;
    }