System.ArgumentException: An item with the same key has already been added. Key: xyz

I’ve created this sample repo to demonstrate the exception outlined in the subject line. The details of the issue have been described in the README.md file of that repo.

Would you please share a solution because renaming public MyRequest Request { get; set; } in both MySubmittedData and YourSubmittedData classes is not feasible? Doing so will lead to other complexities and break the code’s architecture (outside of this repo).

[mark-comeau]

Seems like what is needed is a configuration setting and functionality similar to CustomSchemaIds as implemented here: https://github.com/domaindrivendev/Swashbuckle.AspNetCore#customize-schema-ids.

[tijmenamsing]

I have the same issue with nested generic types. Downgrading to 1.0.0 doesn’t fix it for me either.

Having these combined fails for me with the error message: An item with the same key has already been added. Key: Response_list

• [OpenApiResponseWithBody(statusCode: HttpStatusCode.OK, contentType: MediaTypeNames.Application.Json, bodyType: typeof(Response<List<Version>>))]
• [OpenApiResponseWithBody(statusCode: HttpStatusCode.OK, contentType: MediaTypeNames.Application.Json, bodyType: typeof(Response<List<Endpoint>>))]

I worked around the issue by changing the body types to Response<Version[]> and Response<Endpoint[]>