Extensions.Dictionary

Introduction

The easiest way to start using Extensions.Dictionary is to install it’s Nuget package. In Visual Studio open Package Manager console and type the following:

Install-Package Extensions.Dictionary

In the source file where you will be using Dictionary Extensions import the namespace:

using Extensions.Dictionary;

Sample class:

public class Person
{
    [DataMember(Name = "Name1")]
    public string Firstname { get; set; }

    [IgnoreDataMember]
    public string Lastname { get; set; }
}

Convert an instance to a dictionary:

var person = new Person { Firstname = "foo", Lastname = "bar" };

// Option 1: Convert all public properties and instance fields
var dictionary1 = person.ToDictionary(); 

// Option 2: Same as option 1 + respect DataContract attributes (DataMember / IgnoreDataMember)
var settings = new ConverterSettings { Resolver = new DataContractResolver() };
var dictionary2 = person.ToDictionary(settings);

// dictionary1: <Firstname = foo; Lastname = bar>
// dictionary2: <Name1 = foo>

Convert a dictionary back to it's typed instance:

// Option 1
var person1 = dictionary.ToInstance<Person>();

// Option 2
var settings = new ConverterSettings { Resolver = new DataContractResolver() };
var person2 = dictionary.ToInstance<Person>(settings);

Extensibility

Custom MemberConverter

This sample creates a custom converter from MemberConverter<T> that overrides conversion for the System.Numerics.Vector4 class.

public class Vector4Converter : MemberConverter<Vector4>
{
    public override IDictionary<string, object> ToDictionary(Vector4 value, ConverterSettings settings)
    {
        return new Dictionary<string, object>(4)
        {
            { nameof(Vector4.W), value.W },
            { nameof(Vector4.X), value.X },
            { nameof(Vector4.Y), value.Y },
            { nameof(Vector4.Z), value.Z },
        };
    }

    public override Vector4 ToInstance(IDictionary<string, object?> value, ConverterSettings settings)
    {
        return new Vector4
        {
            W = float.Parse(value[nameof(Vector4.W)]?.ToString(), settings.Culture),
            X = float.Parse(value[nameof(Vector4.X)]?.ToString(), settings.Culture),
            Y = float.Parse(value[nameof(Vector4.Y)]?.ToString(), settings.Culture),
            Z = float.Parse(value[nameof(Vector4.Z)]?.ToString(), settings.Culture),
        };
    }
}

// Usage
var plane = new Plane(1f, 1f, 1f, .1f);

var settings = new ConverterSettings();
settings.Converters.Add(new Vector4Converter());

var dict = plane.ToDictionary(settings);

Custom Resolver

It is possible to customize the member name / value extraction. Just implement the provided ISerializerResolver interface. The following code snipped shows an example of a Json.NET resolver:

public class JsonNetResolver : ISerializerResolver
{
    public string GetMemberName(MemberInfo memberInfo)
    {
        if (memberInfo == null)
        {
            throw new ArgumentNullException(nameof(memberInfo));
        }

        var attribute = memberInfo.GetCustomAttribute<JsonPropertyAttribute>();
        return attribute?.PropertyName ?? memberInfo.Name;
    }

    public object GetMemberValue(MemberInfo memberInfo, object instance)
    {
        switch (memberInfo?.MemberType)
        {
            case MemberTypes.Property:
                return ((PropertyInfo)memberInfo).GetValue(instance);
            case MemberTypes.Field:
                return ((FieldInfo)memberInfo).GetValue(instance);
            case null:
                throw new ArgumentNullException(nameof(memberInfo));
            default:
                throw new NotSupportedException(memberInfo.MemberType + " not supported.");
        }
    }

    public MemberInfo[] GetMemberInfos(Type type)
    {
        return type?
            .GetProperties(BindingFlags.Instance | BindingFlags.Public)
            .Cast<MemberInfo>()
            .Concat(type.GetFields(BindingFlags.Instance | BindingFlags.Public))
            .Where(x => !x.GetCustomAttributes<JsonIgnoreAttribute>().Any())
            ?? Array.Empty<Type>();
    }
}

Benchmarks

The following benchmarks are showing the differences between converting from dictionary to instance and from instance to dictionary. SPOILER: You get the best efficiency with the DefaultResolver.

Test environment

BenchmarkDotNet=v0.12.0, OS=Windows 10.0.18362
Intel Core i7-6700HQ CPU 2.60GHz (Skylake), 1 CPU, 8 logical and 8 physical cores
.NET Core SDK=3.0.100
  [Host]   : .NET Core 3.0.0 (CoreCLR 4.700.19.46205, CoreFX 4.700.19.46214), X64 RyuJIT
  ShortRun : .NET Core 3.0.0 (CoreCLR 4.700.19.46205, CoreFX 4.700.19.46214), X64 RyuJIT 

Convert to dictionary

Method	N	Mean	Error	StdDev	Ratio	RatioSD	Rank	Gen 0	Gen 1	Gen 2	Allocated
DefaultResolver	1	6.277 us	12.242 us	0.6710 us	1.00	0.00	1	0.5875	-	-	1.81 KB
DataContractResolver	1	16.106 us	18.827 us	1.0320 us	2.59	0.35	3	0.9918	-	-	3.07 KB
DataContractResolver-IgnoreAncestors	1	12.773 us	8.038 us	0.4406 us	2.05	0.15	2	0.9766	-	-	3.07 KB
JsonNetResolver	1	50.861 us	56.199 us	3.0805 us	8.14	0.56	4	5.8594	-	-	18 KB
DefaultResolver	10	5.572 us	1.225 us	0.0672 us	1.00	0.00	1	0.5875	-	-	1.81 KB
DataContractResolver	10	14.726 us	33.944 us	1.8606 us	2.64	0.32	3	0.9918	-	-	3.07 KB
DataContractResolver-IgnoreAncestors	10	12.287 us	1.493 us	0.0818 us	2.21	0.03	2	0.9918	-	-	3.07 KB
JsonNetResolver	10	52.918 us	89.842 us	4.9246 us	9.50	1.00	4	5.8594	-	-	18 KB
DefaultResolver	100	6.063 us	4.733 us	0.2595 us	1.00	0.00	1	0.5875	-	-	1.81 KB
DataContractResolver	100	12.419 us	4.004 us	0.2195 us	2.05	0.06	2	0.9918	-	-	3.07 KB
DataContractResolver-IgnoreAncestors	100	12.413 us	13.096 us	0.7179 us	2.05	0.20	2	0.9918	-	-	3.07 KB
JsonNetResolver	100	54.870 us	36.022 us	1.9745 us	9.06	0.50	3	5.8594	-	-	18 KB

Convert to instance

Method	N	Mean	Error	StdDev	Ratio	RatioSD	Rank	Gen 0	Gen 1	Gen 2	Allocated
DefaultResolver	1	10.76 us	0.491 us	0.027 us	1.00	0.00	1	0.7019	-	-	2.18 KB
DataContractResolver	1	53.33 us	61.631 us	3.378 us	4.96	0.32	3	3.7842	-	-	11.72 KB
DataContractResolver-IgnoreAncestors	1	54.74 us	99.851 us	5.473 us	5.09	0.51	4	3.7842	-	-	11.72 KB
JsonNetResolver	1	161.86 us	94.736 us	5.193 us	15.05	0.46	5	16.6016	-	-	51.52 KB
PureJsonNet	1	18.55 us	24.079 us	1.320 us	1.72	0.12	2	2.4414	-	-	7.49 KB
DefaultResolver	10	11.64 us	18.704 us	1.025 us	1.00	0.00	1	0.7019	-	-	2.18 KB
DataContractResolver	10	64.32 us	118.677 us	6.505 us	5.53	0.42	3	3.7842	-	-	11.72 KB
DataContractResolver-IgnoreAncestors	10	54.44 us	22.665 us	1.242 us	4.70	0.40	2	3.7842	-	-	11.72 KB
JsonNetResolver	10	169.81 us	208.025 us	11.403 us	14.66	1.68	5	16.6016	-	-	51.52 KB
PureJsonNet	10	163.40 us	185.507 us	10.168 us	14.10	1.48	4	11.2305	-	-	35.09 KB
DefaultResolver	100	13.51 us	13.977 us	0.766 us	1.00	0.00	1	0.7019	-	-	2.18 KB
DataContractResolver	100	64.19 us	64.332 us	3.526 us	4.76	0.36	3	3.7842	-	-	11.72 KB
DataContractResolver-IgnoreAncestors	100	56.80 us	92.891 us	5.092 us	4.20	0.28	2	3.7842	-	-	11.72 KB
JsonNetResolver	100	138.36 us	34.188 us	1.874 us	10.26	0.44	4	16.6016	-	-	51.52 KB
PureJsonNet	100	1,858.79 us	6,022.705 us	330.125 us	137.79	24.91	5	93.7500	-	-	292.02 KB

Open Source License Acknowledgements and Third-Party Copyrights

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