Aspnetcore: WebApi The collection type 'Newtonsoft.Json.Linq.JToken' is not supported

[AlbertoBonfiglio]

Describe the bug

On a ASPNetcore 3.xx webAPI when a controller action accepts a JObject as parameter, during execution the server throws the following exception. System.NotSupportedException: The collection type 'Newtonsoft.Json.Linq.JToken' is not supported.

It works correctly in 2.2

To Reproduce

Steps to reproduce the behavior:

1. Using AspNetcore 3 preview 7 and 8
2. Run this code '....'
   [HttpPost]
   public ActionResult Post([FromBody] JObject value)
   {
   return Ok(value);
   }
3. With a valid json formatted object
   {
   "id": "3fa85f64-5717-4562-b3fc-2d963f66bfa6",
   "type": "xxx",
   "name": "string",
   "description": "string",
   "reason": "string",
   "submitter": "string",
   "submittedOn": "2019-08-20T00:00:14.128Z",
   "status": 0
   }

1. See error
   500 Internal Server Error

System.NotSupportedException: The collection type 'Newtonsoft.Json.Linq.JToken' is not supported. at System.Text.Json.JsonClassInfo.GetElementType(Type propertyType, Type parentType, MemberInfo memberInfo, JsonSerializerOptions options) at System.Text.Json.JsonClassInfo.CreateProperty(Type declaredPropertyType, Type runtimePropertyType, Type implementedPropertyType, PropertyInfo propertyInfo, Type parentClassType, JsonSerializerOptions options) at System.Text.Json.JsonClassInfo.AddProperty(Type propertyType, PropertyInfo propertyInfo, Type classType, JsonSerializerOptions options) at System.Text.Json.JsonClassInfo.AddPolicyProperty(Type propertyType, JsonSerializerOptions options) at System.Text.Json.JsonClassInfo..ctor(Type type, JsonSerializerOptions options) at System.Text.Json.JsonSerializerOptions.GetOrAddClass(Type classType) at System.Text.Json.JsonClassInfo..ctor(Type type, JsonSerializerOptions options) at System.Text.Json.JsonSerializerOptions.GetOrAddClass(Type classType) at System.Text.Json.JsonSerializer.ReadAsyncTValue at Microsoft.AspNetCore.Mvc.Formatters.SystemTextJsonInputFormatter.ReadRequestBodyAsync(InputFormatterContext context, Encoding encoding) at Microsoft.AspNetCore.Mvc.Formatters.SystemTextJsonInputFormatter.ReadRequestBodyAsync(InputFormatterContext context, Encoding encoding) at Microsoft.AspNetCore.Mvc.ModelBinding.Binders.BodyModelBinder.BindModelAsync(ModelBindingContext bindingContext) at Microsoft.AspNetCore.Mvc.ModelBinding.ParameterBinder.BindModelAsync(ActionContext actionContext, IModelBinder modelBinder, IValueProvider valueProvider, ParameterDescriptor parameter, ModelMetadata metadata, Object value) at Microsoft.AspNetCore.Mvc.Controllers.ControllerBinderDelegateProvider.<>c__DisplayClass0_0.d.MoveNext() --- End of stack trace from previous location where exception was thrown --- at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__Awaited|13_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Logged|17_1(ResourceInvoker invoker) at Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger) at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context) at Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.SetRoutingAndContinue(HttpContext httpContext) at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context) HEADERS ======= Accept: / Accept-Encoding: gzip, deflate Cache-Control: no-cache Connection: keep-alive Content-Length: 237 Content-Type: application/json Host: localhost:44313 User-Agent: PostmanRuntime/7.15.2 Postman-Token: 5fd24880-818b-428c-89f8-97783113fb0c

Expected behavior

It should return the json object and a 200 status code

Screenshots

n/a

Additional context

.NET Core SDK (reflecting any global.json):
Version: 3.0.100-preview8-013656
Commit: 8bf06ffc8d

Runtime Environment:
OS Name: Windows
OS Version: 10.0.18362
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\3.0.100-preview8-013656\

Host (useful for support):
Version: 3.0.0-preview8-28405-07
Commit: d01b2fb7bc

.NET Core SDKs installed:
2.1.700 [C:\Program Files\dotnet\sdk]
2.1.701 [C:\Program Files\dotnet\sdk]
2.1.801 [C:\Program Files\dotnet\sdk]
2.2.300 [C:\Program Files\dotnet\sdk]
2.2.301 [C:\Program Files\dotnet\sdk]
2.2.401 [C:\Program Files\dotnet\sdk]
3.0.100-preview8-013656 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
Microsoft.AspNetCore.All 2.1.11 [C:\Program Files\dotnetshared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.12 [C:\Program Files\dotnetshared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.5 [C:\Program Files\dotnetshared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.6 [C:\Program Files\dotnetshared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.11 [C:\Program Files\dotnetshared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.12 [C:\Program Files\dotnetshared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.5 [C:\Program Files\dotnetshared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.6 [C:\Program Files\dotnetshared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.0.0-preview8.19405.7 [C:\Program Files\dotnetshared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.11 [C:\Program Files\dotnetshared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.12 [C:\Program Files\dotnetshared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.5 [C:\Program Files\dotnetshared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.6 [C:\Program Files\dotnetshared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.0.0-preview8-28405-07 [C:\Program Files\dotnetshared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.0.0-preview8-28405-07 [C:\Program Files\dotnetshared\Microsoft.WindowsDesktop.App]

[pranavkm]

JObject is a Newtonsoft.Json specific type. You'll need to configure your application to add support for it in MVC: https://docs.microsoft.com/en-us/aspnet/core/migration/22-to-30?view=aspnetcore-2.2&tabs=visual-studio#jsonnet-support

[AlbertoBonfiglio]

Sir, I would hug you if I could!

[ffMathy]

I'm getting this in the newly released final version of .NET Core 3.0, even though I have called AddNewtonsoftJson.

[pranavkm]

Hi, it looks like you are posting on a closed issue/PR/commit!

We're very likely to lose track of your bug/feedback/question unless you:

1. Open a new issue
2. Explain very clearly what you need help with
3. If you think you have found a bug, include detailed repro steps so that we can investigate the problem

Thanks!