绑定转换器作为内部类？

我有一个使用绑定转换器的UserControl。 我把转换器变成了一个内部类

public partial class MyPanel : UserControl { public class CornerRadiusConverter : IValueConverter { 

如何从XAML引用Converter类？ 以下不起作用：

它给出了这个错误：

XML命名空间’clr-namespace：MyApp.Windows.Controls’中不存在标签’LensPanel.CornerRadiusConverter’

Answer 1

我再次考虑这个问题，我想出了类似于Dennis解决方案的东西：创建一个带有Type属性的“代理”转换器类，它将创建实际转换器的实例并将转换委托给它。

 public class Converter : IValueConverter { private Type _type = null; public Type Type { get { return _type; } set { if (value != _type) { if (value.GetInterface("IValueConverter") != null) { _type = value; _converter = null; } else { throw new ArgumentException( string.Format("Type {0} doesn't implement IValueConverter", value.FullName), "value"); } } } } private IValueConverter _converter = null; private void CreateConverter() { if (_converter == null) { if (_type != null) { _converter = Activator.CreateInstance(_type) as IValueConverter; } else { throw new InvalidOperationException("Converter type is not defined"); } } } #region IValueConverter Members public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { CreateConverter(); return _converter.Convert(value, targetType, parameter, culture); } public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { CreateConverter(); return _converter.ConvertBack(value, targetType, parameter, culture); } #endregion } 

你这样使用它：

Answer 2

这可能是可能的。 几个月前，我写了一个标记扩展来为你内联创建转换器。 它保留弱引用的字典，以便您不创建同一转换器的多个实例。 处理创建具有不同参数的转换器。

在XAML中：

C＃：

 [MarkupExtensionReturnType(typeof(IValueConverter))] public class InlineConverterExtension : MarkupExtension { static Dictionary s_WeakReferenceLookup; Type m_ConverterType; object[] m_Arguments; static InlineConverterExtension() { s_WeakReferenceLookup = new Dictionary(); } public InlineConverterExtension() { } public InlineConverterExtension(Type converterType) { m_ConverterType = converterType; } /// 
 /// The type of the converter to create /// 
 /// The type of the converter. public Type ConverterType { get { return m_ConverterType; } set { m_ConverterType = value; } } /// 
 /// The optional arguments for the converter's constructor. /// 
 /// The argumments. public object[] Arguments { get { return m_Arguments; } set { m_Arguments = value; } } public override object ProvideValue(IServiceProvider serviceProvider) { IProvideValueTarget target = (IProvideValueTarget)serviceProvider.GetService(typeof(IProvideValueTarget)); PropertyInfo propertyInfo = target.TargetProperty as PropertyInfo; if (!propertyInfo.PropertyType.IsAssignableFrom(typeof(IValueConverter))) throw new NotSupportedException("Property '" + propertyInfo.Name + "' is not assignable from IValueConverter."); System.Diagnostics.Debug.Assert(m_ConverterType != null, "ConverterType is has not been set, ConverterType{x:Type converterType}"); try { string key = m_ConverterType.ToString(); if (m_Arguments != null) { List args = new List(); foreach (object obj in m_Arguments) args.Add(obj.ToString()); key = String.Concat(key, "_", String.Join("|", args.ToArray())); } WeakReference wr = null; if (s_WeakReferenceLookup.TryGetValue(key, out wr)) { if (wr.IsAlive) return wr.Target; else s_WeakReferenceLookup.Remove(key); } object converter = (m_Arguments == null) ? Activator.CreateInstance(m_ConverterType) : Activator.CreateInstance(m_ConverterType, m_Arguments); s_WeakReferenceLookup.Add(key, new WeakReference(converter)); return converter; } catch(MissingMethodException) { // constructor for the converter does not exist! throw; } } } 

Answer 3

我所做的是：

然后在控制中