"Human" 的TypeConvert不支持从字符串进行转换

程序能正常运行，但是xaml报错，设计器显示不出来，重写CanConvertFrom解决，代码如下

    public class StringToHumanTypeConvert:TypeConverter
    {
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
        {
            return sourceType == typeof(string);
        }

        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
        {
            string name = value.ToString();
            Human child = new Human();
            child.Name = name;
            return child;
        }
    }