单选按钮的 WPF 转换器不起作用

Question

我有两个绑定到同一属性的单选按钮。单选按钮有 2 个转换器。但第二个复选框的转换仅发生第一次。代码中是否有问题。

<RadioButton Margin="5,1" GroupName="groupValueOrTime" Name="radioButtonTimeDriven" VerticalAlignment="Top" IsChecked="{Binding Path=TriggerType ,Converter={StaticResource dailyTriggerConverter}}"  Grid.Column="0" Grid.Row="0" >Time Driven</RadioButton>
<RadioButton Margin="5,1" GroupName="groupValueOrTime" Name="radioButtonValueDriven" VerticalAlignment="Top" Grid.Column="0" Grid.Row="1" IsChecked="{Binding Path=TriggerType,Converter={StaticResource valueDrivenTriggerConverter}}" >Value Driven</RadioButton>

代码：

public class TriggerTypeDailyToBoolProperty:IValueConverter
{
    #region IValueConverter Members

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
       //convert from TriggerType to bool:
        int TriggerType=int.Parse(value.ToString());
        if (TriggerType == 0 || TriggerType == 1 || TriggerType == 2 || TriggerType == 3 || TriggerType == 4 || TriggerType == 5 || TriggerType == 6)
            return true;
        else
            return false;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        bool isChecked = (bool)value;
        return (isChecked? 0: -1);
    }

    #endregion
}

public class TriggerTypeValueDrivenToBoolProperty : IValueConverter
{
   #region IValueConverter Members

   public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
   {
       //convert from TriggerType to bool:
       int TriggerType = int.Parse(value.ToString());
       if (TriggerType == 9)
           return true;
       else
           return false;
   }

   public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
   {
       bool isChecked = (bool)value;
       return (isChecked ? 9 : -1);
   }

   #endregion
}

Answer 1

组合分组、单选按钮和绑定不起作用。绑定的一个奇怪功能是，如果您在代码中设置绑定目标属性的值，则会禁用绑定。绑定设计似乎做出的假设是，更改目标属性的唯一方法是使用 UI 或更改其绑定到的源属性，并且如果一段代码显式设置绑定的值目标属性，它知道它在做什么。

不幸的是，这意味着分组单选按钮（在更改时在代码中设置彼此的值）在用户单击它们时会破坏它们的绑定。哎呀。

解决方案很简单：将单选按钮绑定到视图模型中的属性，消除分组，并将逻辑放入视图模型中以处理绑定属性的互斥性质，例如：

private bool _Option1;

public bool Option1
{
   get { return _Option1; }
   set
   {
      if (value != _Option1)
      {
         _Option1 = value;
         if (value)
         {
            Option2 = false;
            Option3 = false;
         }
      }
      OnPropertyChanged("Option1");
   }
}

Answer 2

我认为您的视图模型中需要有两个不同的布尔属性。

请参考下面描述视图模型的示例。

public class TriggerViewModel : INotifyPropertyChanged
{
    private bool _triggerTypeValue;
    private bool _triggerTypeTime;
    public bool TriggerTypeValue
    {
        get
        {
            return _triggerTypeValue;
        }
        set
        {
            _triggerTypeValue = value;
            OnPropertychanged("TriggerTypeValue");
            SetTriggerTypeTime(!_triggerTypeValue);
        }
    }

    public bool TriggerTypeTime
    {
        get
        {
            return _triggerTypeTime;
        }
        set
        {
            _triggerTypeTime = value;
            OnPropertychanged("TriggerTypeTime");
            SetTriggerTypeValue(!_triggerTypeTime);
        }
    }

    public TriggerViewModel()
    {
        _triggerTypeValue = false;
        _triggerTypeTime = true;
    }

    private void SetTriggerTypeTime(bool value)
    {
        _triggerTypeTime = value;
        OnPropertychanged("TriggerTypeTime");
    }

    private void SetTriggerTypeValue(bool value)
    {
        _triggerTypeValue = value;
        OnPropertychanged("TriggerTypeValue");
    }

    private void OnPropertychanged(string propertyName)
    {
        if(PropertyChanged!= null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
}

对于 XAML

<RadioButton Margin="5,1" GroupName="groupValueOrTime" Name="radioButtonTimeDriven" 
             VerticalAlignment="Top" IsChecked="{Binding Path=TriggerType}"  
             Grid.Column="0" Grid.Row="0">
     Time Driven 
</RadioButton>

<RadioButton Margin="5,1" GroupName="groupValueOrTime" Name="radioButtonValueDriven" 
             VerticalAlignment="Top" Grid.Column="0" Grid.Row="1" 
             IsChecked="{Binding Path=TriggerType}">
      Value Driven
<RadioButton>

注意：此方法删除了转换器，并允许您将业务逻辑保留在中央视图模型中。