#4337 added initial implementation points.

modules/feature-management/src/Volo.Abp.FeatureManagement.Application.Contracts/Volo/Abp/FeatureManagement/AbpFeatureManagementApplicationContractsModule.cs

@@ -1,4 +1,5 @@
 using Volo.Abp.Application;
+using Volo.Abp.Json.Newtonsoft;
 using Volo.Abp.Modularity;
 using Volo.Abp.VirtualFileSystem;
 
@@ -16,6 +17,11 @@ namespace Volo.Abp.FeatureManagement
             {
                 options.FileSets.AddEmbedded<AbpFeatureManagementApplicationContractsModule>();
             });
+
+            Configure<AbpNewtonsoftJsonSerializerOptions>(options =>
+            {
+                options.Converters.Add<StringValueTypeJsonConverter>();
+            });
         }
     }
 }

modules/feature-management/src/Volo.Abp.FeatureManagement.Application.Contracts/Volo/Abp/FeatureManagement/StringValueTypeJsonConverter.cs

@@ -0,0 +1,29 @@
+using System;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+using Volo.Abp.DependencyInjection;
+using Volo.Abp.Validation.StringValues;
+
+namespace Volo.Abp.FeatureManagement
+{
+    public class StringValueTypeJsonConverter : JsonConverter, ITransientDependency
+    {
+        public override bool CanWrite => false;
+
+        public override bool CanConvert(Type objectType)
+        {
+            return objectType == typeof(IStringValueType);
+        }
+
+        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        {
+            throw new NotImplementedException("This method should not be called to write (since CanWrite is false).");
+        }
+
+        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        {
+            //TODO: Deserialize!
+            return null;
+        }
+    }
+}

modules/feature-management/test/Volo.Abp.FeatureManagement.Application.Tests/Volo/Abp/FeatureManagement/FeatureAppService_Tests.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
 using System.Threading.Tasks;
 using Microsoft.Extensions.DependencyInjection;
 using NSubstitute;

modules/feature-management/test/Volo.Abp.FeatureManagement.Application.Tests/Volo/Abp/FeatureManagement/StringValueJsonConverter_Tests.cs

@@ -0,0 +1,46 @@
+using System.Collections.Generic;
+using Newtonsoft.Json;
+using Shouldly;
+using Volo.Abp.Json;
+using Volo.Abp.Validation.StringValues;
+using Xunit;
+
+namespace Volo.Abp.FeatureManagement
+{
+    public class StringValueJsonConverter_Tests : FeatureManagementApplicationTestBase
+    {
+        private readonly IJsonSerializer _jsonSerializer;
+
+        public StringValueJsonConverter_Tests()
+        {
+            _jsonSerializer = GetRequiredService<IJsonSerializer>();
+        }
+
+        [Fact(Skip = "StringValueTypeJsonConverter is not implemented yet!")]
+        public void Should_Serialize_And_Deserialize()
+        {
+            var featureListDto = new FeatureListDto
+            {
+                Features = new List<FeatureDto>
+                {
+                    new FeatureDto
+                    {
+                        ValueType = new FreeTextStringValueType
+                        {
+                            Validator = new BooleanValueValidator()
+                        }
+                    }
+
+                    //TODO: Add more to test
+                }
+            };
+
+            var serialized = _jsonSerializer.Serialize(featureListDto);
+
+            var featureListDto2 = _jsonSerializer.Deserialize<FeatureListDto>(serialized);
+
+            featureListDto2.Features[0].ValueType.ShouldBeOfType<FreeTextStringValueType>();
+            featureListDto2.Features[0].ValueType.Validator.ShouldBeOfType<BooleanValueValidator>();
+        }
+    }
+}