Xamarin自定义MarkupExtension不使用类型属性

您需要在此处使用嵌套标记扩展(您已经使用过);但还需要指定属性的名称。否则,我的测试显示,它被视为一个字符串值并分配给默认内容属性-因此,类型不匹配。

<Label Text="{local:TypeMarkup TheType={x:Type x:Int16}}" ../>

选项2:使用Xaml类型解析器

你可以用 XamlTypeResolver (参考: TypeExtension in Xamarin.Forms )

[ContentProperty(nameof(TheType))]
public class TypeMarkupExtension : IMarkupExtension
{
    public string TheType { get; set; }

    public object ProvideValue(IServiceProvider serviceProvider)
    {
        if (string.IsNullOrEmpty(TheType))
            throw new InvalidOperationException("TheType isn't set.");

        if (serviceProvider == null)
            throw new ArgumentNullException(nameof(serviceProvider));

        var typeResolver = serviceProvider.GetService(typeof(IXamlTypeResolver)) as IXamlTypeResolver;
        if (typeResolver == null)
            throw new ArgumentException("No IXamlTypeResolver in IServiceProvider");

        var resolvedType = typeResolver.Resolve(TheType, serviceProvider);
        return resolvedType?.FullName ?? "Failure";
    }
}