[BUG] 🐞 ToQueryString does not work properly when source type has TypeConverter

[candoumbe]

Usage Information

Package version : 0.5.1

Relevant Code / Invocations

public static class StronglyTypedIdHelper
    {
        private static readonly ConcurrentDictionary<Type, Delegate> StronglyTypedIdFactories = new();

        public static Func<TValue, object> GetFactory<TValue>(Type stronglyTypedIdType)
            where TValue : notnull
        {
            return (Func<TValue, object>)StronglyTypedIdFactories.GetOrAdd(
                stronglyTypedIdType,
                CreateFactory<TValue>);
        }

        private static Func<TValue, object> CreateFactory<TValue>(Type stronglyTypedIdType)
            where TValue : notnull
        {
            if (!IsStronglyTypedId(stronglyTypedIdType))
            {
                throw new ArgumentException($"Type '{stronglyTypedIdType}' is not a strongly-typed id type", nameof(stronglyTypedIdType));
            }

            System.Reflection.ConstructorInfo ctor = stronglyTypedIdType.GetConstructor(new[] { typeof(TValue) });
            if (ctor is null)
            {
                throw new ArgumentException($"Type '{stronglyTypedIdType}' doesn't have a constructor with one parameter of type '{typeof(TValue)}'", nameof(stronglyTypedIdType));
            }

            ParameterExpression param = Expression.Parameter(typeof(TValue), "value");
            NewExpression body = Expression.New(ctor, param);
            Expression<Func<TValue, object>> lambda = Expression.Lambda<Func<TValue, object>>(body, param);

            return lambda.Compile();
        }

        public static bool IsStronglyTypedId(Type type) => IsStronglyTypedId(type, out _);

        public static bool IsStronglyTypedId(Type type, [NotNullWhen(true)] out Type idType)
        {
            if (type is null)
            {
                throw new ArgumentNullException(nameof(type));
            }

            bool isStronglyType = false;
            if (type.BaseType is Type baseType &&
                baseType.IsGenericType &&
                baseType.GetGenericTypeDefinition() == typeof(StronglyTypedId<>))
            {
                idType = baseType.GetGenericArguments()[0];
                isStronglyType = true;
            }
            else if (type.BaseType == typeof(StronglyTypedGuidId))
            {
                idType = typeof(Guid);
                isStronglyType = true;
            }
            else
            {
                idType = null;
            }

            return isStronglyType;
        }
    }

public class StronglyTypedIdConverter<TValue> : TypeConverter where TValue : notnull
    {
        private static readonly TypeConverter IdValueConverter = GetIdValueConverter();

        private static TypeConverter GetIdValueConverter()
        {
            TypeConverter converter = TypeDescriptor.GetConverter(typeof(TValue));
            if (!converter.CanConvertFrom(typeof(string)))
            {
                throw new InvalidOperationException(
                    $"Type '{typeof(TValue)}' doesn't have a converter that can convert from string");
            }

            return converter;
        }

        private readonly Type _type;
        public StronglyTypedIdConverter(Type type)
        {
            _type = type;
        }

        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
        {
            return sourceType == typeof(string)
                || sourceType == typeof(TValue)
                || base.CanConvertFrom(context, sourceType);
        }

        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            return destinationType == typeof(string)
                || destinationType == typeof(TValue)
                || base.CanConvertTo(context, destinationType);
        }

        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
        {
            if (value is string s)
            {
                value = IdValueConverter.ConvertFrom(s);
            }

            object result;

            if (value is TValue idValue)
            {
                Func<TValue, object> factory = StronglyTypedIdHelper.GetFactory<TValue>(_type);
                result = factory(idValue);
            }
            else
            {
                result = base.ConvertFrom(context, culture, value);
            }

            return result;
        }

        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
        {
            if (value is null)
            {
                throw new ArgumentNullException(nameof(value));
            }

            StronglyTypedId<TValue> stronglyTypedId = (StronglyTypedId<TValue>)value;
            TValue idValue = stronglyTypedId.Value;

            object result;

            if (destinationType == typeof(string))
            {
                result = idValue.ToString()!;
            }
            else if (destinationType == typeof(TValue))
            {
                result = idValue;
            }
            else
            {
                result = base.ConvertTo(context, culture, value, destinationType);
            }

            return result;
        }
    }



[TypeConverter(typeof(StronglyTypedIdConverter))]
public abstract record StronglyTypedId<TValue>
        where TValue : notnull
    {
        public TValue Value { get; }

        protected StronglyTypedId(TValue value) => Value = value;

        public override string ToString() => Value.ToString();
    }

public record Identifier : StronglyTypedId<Guid>(Value)
{
    public static Identifier New() => new(Guid.NewGuid());
}

and a RouteValueDictionary instance as follow

RouteValueDictionary routeValues = new() {
    ["simpleId"] = "abc",
    ["strongId"] = Identifier.New()
};

routesValue.ToQueryString() // "simpleId=abc"

Expected Behavior

Given that there is a TypeConverterthat can convert to a primitive type, the consumer of the library would expect the output to be simpleId=abc&strongId=<value of the guid>

Stacktrace / Exception

[candoumbe]

One way to circumvent the issue is to use the ToQueryString overload that take a Func<(string, object), object>to unwrap the underlying value.

routesValue.ToQueryString((string key, object value) => (value as StronglyTypedId<Guid>)?.Value, ?? value)