JsonException: A possible object cycle was detected which is not supported. This can either be due to a cycle or if the object depth is larger than

Question

In my web api when i run project for get data from database got this error .net core 3.1

JsonException: A possible object cycle was detected which is not

Answer 1

For net core 3.1 you have to add in Startup.cs:

services.AddMvc.AddJsonOptions(o => {
o.JsonSerializerOptions.ReferenceHandler = ReferenceHandler.Preserve;
o.JsonSerializerOptions.MaxDepth = 0;
})

and import at least this package using nuget.org include prerelease: