我有一个实现了IValueConverter
接口的类,旨在将布尔值转换为Brush
。我正在尝试将IValueConverter
用于将BorderBrush
属性绑定到Border
控件上:
<Window x:Class="DomPicker.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:cc="clr-namespace:CustomControls;assembly=CustomControls"
xmlns:sys="clr-namespace:System;assembly=mscorlib"
DataContext="{Binding Path=Domains, RelativeSource={RelativeSource Self}}"
Height="350"
Title="My Title"
Width="525">
<cc:CarSystemWindow.Resources>
<cc:BooleanToBrushConverter x:Key="BrushConverter" True="Black" False="Transparent" />
<DataTemplate x:Name="DomainTemplate" DataType="DomainViewModel">
<Border BorderBrush="{Binding Converter=BrushConverter, Path=IsSelected}">
. . .
</Border>
</DataTemplate>
</cc:CarSystemWindow.Resources>
<Grid>
<ListBox . . . Name="DomainListBox" />
</Grid>
<Window>
以下是代码后端中 Domains 属性的代码:
public static readonly DependencyProperty DomainsProperty =
DependencyProperty.Register( "Domains", typeof( ObservableCollection<DomainViewModel> ), typeof( MainWindow ), new PropertyMetadata( null ) );
public ObservableCollection<DomainViewModel> Domains {
get { return (ObservableCollection<DomainViewModel>) GetValue( DomainsProperty ); }
set { SetValue( DomainsProperty, value ); }
}
当我编译代码时(这并不代表它已经完成),在BorderBrush
绑定处出现编译器错误:
The TypeConverter for "IValueConverter" does not support converting from a string.
这是 IValueConverter
的代码:
public class BooleanConverter<T> : IValueConverter {
public T False { get; set; }
public T True { get; set; }
public BooleanConverter( T trueValue, T falseValue ) {
// Set the values of True and false to the values we were passed.
True = trueValue;
False = falseValue;
}
public object Convert( object value, Type targetType, object parameter, CultureInfo culture ) {
return value is bool && ( (bool) value ) ? True : False;
}
public object ConvertBack( object value, Type targetType, object parameter, CultureInfo culture ) {
return value is T && EqualityComparer<T>.Default.Equals( (T) value, True );
}
}
[ValueConversion( typeof( bool ), typeof( Brush ) )]
public class BooleanToBrushConverter : BooleanConverter<Brush> {
/// <summary>
/// Set us up so we convert true to a Black <see cref="SolidColorBrush"/> and
/// false to a Red SolidColorBrush.
/// </summary>
public BooleanToBrushConverter() :
base( new SolidColorBrush( Colors.Black ), new SolidColorBrush( Colors.Red ) ) { }
}
有人能告诉我我做错了什么吗?