- 代码经常遇到类型A转换到类型C，但是已经写好类型A转换到类型B、类型B转换类型C。往往遇到这种情况，通常会重新写过一个转换器来进行满足需求。以下是解决该痛点。
/// <summary>
/// 转换器组转换器
/// </summary>
[ContentProperty(nameof(Converters))]
public class ValueConverterGroup : IValueConverter
{public List<IValueConverter> Converters { get; set; } = new List<IValueConverter>();public object Convert(object value, Type targetType, object parameter, CultureInfo culture){if (this.Converters is IEnumerable<IValueConverter> converters){return converters.Aggregate(value, (current, converter) => converter.Convert(current, targetType, parameter, culture));}return DependencyProperty.UnsetValue;}public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture){if (this.Converters is IEnumerable<IValueConverter> converters){return converters.Reverse().Aggregate(value, (current, converter) => converter.ConvertBack(current, targetType, parameter, culture));}return DependencyProperty.UnsetValue;}
}
<local:ValueConverterGroup x:Key="StringToVisibilityConvert"><local:StringToUpperConvert /><local:StringToVisibilityConvert /></local:ValueConverterGroup>
- 使用MarkupExtension进行封装转换器
public abstract class ValueConverterBase : MarkupExtension, IValueConverter{public abstract object Convert(object value, Type targetType, object parameter, CultureInfo culture);public virtual object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture){return Binding.DoNothing;}public override object ProvideValue(IServiceProvider serviceProvider){return this;}}
使用该类封装StringToUpperConvert
//使用： <TextBlock Text="{Binding TestText, Mode=OneWay, UpdateSourceTrigger=PropertyChanged, Converter={local:StringToUpperConvert}}" />public class StringToUpperConvert : ValueConverterBase{public override object Convert(object value, Type targetType, object parameter, CultureInfo culture){if (value is not null && value is string){return ((string)value).ToUpper();}return Binding.DoNothing;}}
3.转换器单例
//使用：<TextBlock Text="{Binding TestText, Converter={x:Static local:StringToUpperConvert.Instance}}" />public class StringToUpperConvert : IValueConverter{public static StringToUpperConvert Instance { get;set; } = new StringToUpperConvert();public object Convert(object value, Type targetType, object parameter, CultureInfo culture){if (value is not null && value is string){return ((string)value).ToUpper();}return Binding.DoNothing;}public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture){return DependencyProperty.UnsetValue;}}
