C# WPF IsEnabled 使用多个绑定？

Question

我有一个描述 GUI 部分的 WPF xaml 文件，我希望特定控件的启用/禁用依赖于其他两个控件。 代码目前看起来像这样：

<ComboBox Name="MyComboBox"
          IsEnabled="{Binding ElementName=SomeCheckBox, Path=IsChecked}"/>

但我希望它也依赖于另一个复选框，因此类似于：

<ComboBox Name="MyComboBox"
          IsEnabled="{Binding ElementName=SomeCheckBox&AnotherCheckbox, Path=IsChecked}"/>

最好的方法是什么？ 我不禁觉得我错过了一些明显的东西或者以错误的方式处理这件事？

Answer 1

您可以使用MultiBinding 使用实现 < 的转换器代码>IMultiValueConverter。

只是为了给出答案，您可以（几乎）复制和粘贴：

所需的静态资源：

<converterNamespace:BooleanAndConverter x:Key="booleanAndConverter" />

组合框：

<ComboBox Name="MyComboBox">
  <ComboBox.IsEnabled>
    <MultiBinding Converter="{StaticResource booleanAndConverter}">
      <Binding ElementName="SomeCheckBox" Path="IsChecked" />
      <Binding ElementName="AnotherCheckbox" Path="IsChecked"  />
    </MultiBinding>
  </ComboBox.IsEnabled>
</ComboBox>

转换器的代码：

namespace ConverterNamespace
{
    public class BooleanAndConverter : IMultiValueConverter
    {
        public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            foreach (object value in values)
            {
                if ((value is bool) && (bool)value == false)
                {
                    return false;
                }
            }
            return true;
        }
        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotSupportedException("BooleanAndConverter is a OneWay converter.");
        }
    }
}

Answer 2

您也可以尝试相同的较短版本：

public class BooleanAndConverter : IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return values.OfType<IConvertible>().All(System.Convert.ToBoolean);
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotSupportedException();
    }
}

public class BooleanOrConverter : IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return values.OfType<IConvertible>().Any(System.Convert.ToBoolean);
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotSupportedException();
    }
}

当然，您可能也需要转换器来提高可见性：

public class BooleanOrToVisibilityConverter : IMultiValueConverter
{
    public Visibility HiddenVisibility { get; set; }

    public bool IsInverted { get; set; }

    public BooleanOrToVisibilityConverter()
    {
        HiddenVisibility = Visibility.Collapsed;
        IsInverted = false;
    }

    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        bool flag = values.OfType<IConvertible>().Any(System.Convert.ToBoolean);
        if (IsInverted) flag = !flag;
        return flag ? Visibility.Visible : HiddenVisibility;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

public class BooleanAndToVisibilityConverter : IMultiValueConverter
{
    public Visibility HiddenVisibility { get; set; }

    public bool IsInverted { get; set; }

    public BooleanAndToVisibilityConverter()
    {
        HiddenVisibility = Visibility.Collapsed;
        IsInverted = false;
    }

    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        bool flag = values.OfType<IConvertible>().All(System.Convert.ToBoolean);
        if (IsInverted) flag = !flag;
        return flag ? Visibility.Visible : HiddenVisibility;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

Answer 3

我相信您可能必须将 MultiBinding 与 MultiValueConverter 一起使用。 请参阅此处：http://www.developingfor.net/wpf/multibinding-in- wpf.html

这是一个直接相关的示例：http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/5b9cd042-cacb-4aaa-9e17-2d615c44ee22

Answer 4

作为 qqbenq 答案的扩展：

添加了处理 Collection 的 Count 的函数，例如，如果您想检查 ListView 的某些项目是否被选择。

转换器：

public class IsEnabledConverter : IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        foreach (var value in values)
        {
            switch (value)
            {
                case bool b when !b:
                case int i when i == 0:
                    return false;
            }
        }

        return true;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        return null;
    }
}

命名空间

按钮

<Button x:Name="MyButton">
    <Button.IsEnabled>
        <MultiBinding Converter="{StaticResource IsEnabledConverter}">
            <Binding ElementName="MyListView" Path="SelectedItems.Count"/>
            <Binding ElementName="MyCheckBox" Path="IsChecked"/>
        </MultiBinding>
    </Button.IsEnabled>
</Button>

Answer 5

当您不想

public class AndEnabledTextBox : TextBox
{
    public static readonly DependencyProperty AndEnabled1SubProperty =
        DependencyProperty.Register(nameof(AndEnabled1), typeof(bool), typeof(AndEnabledTextBox), new FrameworkPropertyMetadata(new PropertyChangedCallback(OnAndEnabledPropertyChanged)));
    public static readonly DependencyProperty AndEnabled2SubProperty =
        DependencyProperty.Register(nameof(AndEnabled2), typeof(bool), typeof(AndEnabledTextBox), new FrameworkPropertyMetadata(new PropertyChangedCallback(OnAndEnabledPropertyChanged)));
    public bool AndEnabled1 { get { return (bool)GetValue(AndEnabled1SubProperty); } set { SetValue(AndEnabled1SubProperty, value); } }
    public bool AndEnabled2 { get { return (bool)GetValue(AndEnabled2SubProperty); } set { SetValue(AndEnabled2SubProperty, value); } }
    protected override void OnInitialized(EventArgs e)
    {
        base.OnInitialized(e);
        IsEnabled = AndEnabled1 && AndEnabled2;
    }
    protected static void OnAndEnabledPropertyChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
    {
        AndEnabledTextBox textBox = (AndEnabledTextBox)obj;
        textBox.IsEnabled = textBox.AndEnabled1 && textBox.AndEnabled2;
    }
}

在此处使用 MultiBinding XAML 代码时（当您使用继承的控件时会更加简化）。

<Window x:Class="WpfApp1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:WpfApp1">
    <StackPanel>
        <ToggleButton x:Name="switch1" Content="{Binding ElementName=switch1, Path=IsChecked}"/>
        <ToggleButton x:Name="switch2" Content="{Binding ElementName=switch2, Path=IsChecked}"/>
        <local:AndEnabledTextBox Text="TEXT"
                                 AndEnabled1="{Binding ElementName=switch1, Path=IsChecked, Mode=OneWay}"
                                 AndEnabled2="{Binding ElementName=switch2, Path=IsChecked, Mode=OneWay}"/>
    </StackPanel>
</Window>