从 Postman 调用简单的 C# Web 服务方法时出现问题

Question

I created a really simple webservice using C#

    using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;

namespace Receival
{
    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    
    public class ReceiveService : System.Web.Services.WebService
    {
        [WebMethod]
        public string HelloWorld()
        {
            return "Hello World";
        }

        [WebMethod]
        public string Mirror(string request)
        {
            return request;
        }
    }
}

I am using Postman to test.

The HelloWorld() works OK

The Mirror() returns error:

System.InvalidOperationException: Request format is invalid: text/plain. at System.Web.Services.Protocols.HttpServerProtocol.ReadParameters()
at System.Web.Services.Protocols.WebServiceHandler.CoreProcessRequest()

whatever the ContentType I use in the PostMan Request header

Any help appreciated. Thank you

Answer 1

'Request' is a.Net object - convert to a string type like text/json/html before returning.