绑定转换器内部类？ [英] Binding converter as inner class?

问题描述

我有一个使用绑定转换器用户控件。我做了该转换器的内部类的

 公共部分类MyPanel：用户控件
{
    公共类CornerRadiusConverter：的IValueConverter
    {
 

我如何从XAML引用转换器类？下面不工作：

 ＆LT;控制：MyPanel.CornerRadiusConverter X：关键=CornerRadiusConverter/＆GT;
 

这给出了这样的错误：

  

标签   LensPanel.CornerRadiusConverter'呢   在XML命名空间不存在   CLR命名空间：MyApp.Windows.Controls

解决方案

我在想这个问题又来了，我想出了类似丹尼斯的解决方案的东西：创建一个代理转换器类，用类属性，将创建实际的转换器的实例，并转化委托给它。

 公共类转换器：的IValueConverter
{
    私有类型_type = NULL;
    公共类型类型
    {
        {返回_type; }
        组
        {
            如果（值！= _type）
            {
                如果（value.GetInterface（的IValueConverter）！= NULL）
                {
                    _type =价值;
                    _CONVERTER = NULL;
                }
                其他
                {
                    抛出新的ArgumentException（
                        的String.Format（类型{0}未实现的IValueConverter，value.FullName）
                        值）;
                }
            }
        }
    }

    私人的IValueConverter _CONVERTER = NULL;
    私人无效CreateConverter（）
    {
        如果（_CONVERTER == NULL）
        {
            如果（_type！= NULL）
            {
                _CONVERTER = Activator.CreateInstance（_type）作为的IValueConverter;
            }
            其他
            {
                抛出新的InvalidOperationException异常（转换器类型没有定义）;
            }
        }
    }

    ＃地区的IValueConverter会员

    公共对象转换（对象的值，类型TARGETTYPE，对象参数，System.Globalization.CultureInfo文化）
    {
        CreateConverter（）;
        返回_converter.Convert（值，TARGETTYPE，参数，文化）;
    }

    公共对象ConvertBack（对象的值，类型TARGETTYPE，对象参数，System.Globalization.CultureInfo文化）
    {
        CreateConverter（）;
        返回_converter.ConvertBack（值，TARGETTYPE，参数，文化）;
    }

    #endregion
}
 

您使用它这样的：

 ＆LT; Window.Resources＆GT;
    ＆LT;我：转换器X：关键=CornerRadiusConverter类型={X：类型的控件：MyPanel + CornerRadiusConverter}/＆GT;
＆LT; /Window.Resources>
 

I have a UserControl that uses a binding converter. I've made the converter an inner class of

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

How do I reference the Converter class from the XAML? The following does not work:

<controls:MyPanel.CornerRadiusConverter x:Key="CornerRadiusConverter" />

It gives this error:

The tag 'LensPanel.CornerRadiusConverter' does not exist in XML namespace 'clr-namespace:MyApp.Windows.Controls'

解决方案

I was thinking about this problem again, and I came up with something similar to Dennis's solution : create a "proxy" converter class, with a Type property, which will create the instance of the actual converter and delegate the conversion to it.

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
}

You use it like that :

<Window.Resources>
    <my:Converter x:Key="CornerRadiusConverter" Type="{x:Type controls:MyPanel+CornerRadiusConverter}"/>
</Window.Resources>

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