[英]Odd behavior when trying to change a bound RadioButton in WPF
我已经将Child
窗口中的两个单选按钮绑定到在主窗口中构造的ViewModel
的Enum
。 绑定按预期工作,但我注意到一个无法解决的异常行为。 我在这里提供了所有代码,因此您可以轻松地自行解决问题。
下面是查看此异常行为的步骤:
RadioButton
更改为Automatic。 它不会改变! <Window x:Class="RadioButtonBinding.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Button Content="Display Child Window" Click="DisplayChildWindow"/>
</Window>
public partial class MainWindow
{
public MainWindow()
{
InitializeComponent();
var viewModel = new ViewModel();
DataContext = viewModel;
}
private void DisplayChildWindow(object sender, RoutedEventArgs e)
{
var win = new ChildWindow {DataContext = (ViewModel) DataContext};
win.ShowDialog();
}
}
<Window x:Class="RadioButtonBinding.ChildWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:radioButtonBinding="clr-namespace:RadioButtonBinding"
Title="ChildWindow" Height="300" Width="300">
<Window.Resources>
<radioButtonBinding:EnumBooleanConverter x:Key="EnumBooleanConverter"/>
</Window.Resources>
<StackPanel>
<RadioButton Content="Automatic"
GroupName="CalcMode"
IsChecked="{Binding Path=CalcMode,
Converter={StaticResource EnumBooleanConverter},
ConverterParameter={x:Static radioButtonBinding:CalcMode.Automatic}}"/>
<RadioButton Content="Custom"
GroupName="CalcMode"
IsChecked="{Binding Path=CalcMode,
Converter={StaticResource EnumBooleanConverter},
ConverterParameter={x:Static radioButtonBinding:CalcMode.User}}"/>
</StackPanel>
</Window>
public class ViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private CalcMode calcMode = CalcMode.User;
public CalcMode CalcMode
{
get { return calcMode; }
set
{
calcMode = value;
RaisePropertyChanged("CalcMode");
}
}
private void RaisePropertyChanged(string propertyName)
{
var handler = PropertyChanged;
if (handler == null) return;
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
public class EnumBooleanConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
var paramEnum = parameter as Enum;
var valueEnum = value as Enum;
return Equals(paramEnum, valueEnum);
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
var parameterEnum = parameter as Enum;
if (parameterEnum == null)
return DependencyProperty.UnsetValue;
return parameterEnum;
}
}
public enum CalcMode : byte
{
Automatic,
User,
}
更新:
我怀疑一定是Converter
但我不知道为什么? 它只是陷入一个循环。
编辑如何将枚举转换为bool,如下所示?
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
if (parameter == null || !(bool)value)
return DependencyProperty.UnsetValue;
var parameterEnum = parameter as Enum;
return parameterEnum;
}
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