c#通用转换器

Question

我有一个转换器，可以让我在 SelectedItems 和 Generic List<MyType> 之间进行转换

public class SelectedTiposDocsToList : BaseConverter, IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        var Selecteditems = value as IList;
        List<MyType> MyTypeList = Selecteditems.Cast<MyType>().ToList();
        return MyTypeList;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
} 

现在这对我来说是一个常见的任务，我想扩展这个类以允许泛型类型是这样的吗？

public class SelectedTiposDocsToList : BaseConverter, IValueConverter
{
    public object Convert<T>(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        var Selecteditems = value as IList;
        List<T> MyTypeList = Selecteditems.Cast<T>().ToList();
        return MyTypeList;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
} 

这可能吗？如果是.. 如何在 XAML 上使用这种类型的转换器？

Answer 1

不，这不是 IValueConverter 的有效实现。但是，您可以在参数上传递一个类型:

{Binding MyVariable, Converter={StaticResource SelectedTiposDocsToList}, ConverterParameter={x:Type local:MyType}}

然后您将使用 Select 和 Convert.ChangeType 方法:MSDN

public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
    var Selecteditems = value as IList;
    var MyTypeList = Selecteditems.Cast<object>().Select((i) => System.Convert.ChangeType(i, parameter as Type)).ToList();
    return MyTypeList;
}

已验证为在 VS 2013 上编译。