如何在WCF中实现MessageContract？

Question

好的，这是场景！ 我知道我肯定会犯一些错误，但是我想弄清楚基础知识，并希望成功实现它们。 我有一个Employee类，它是WCF中的DataContract，FullTimeEmployee和PartTimeEmployee扩展了该类。 在我的EmployeeService中，我们分别根据来自控制台应用程序客户端的用户输入返回FullTimeEmployee和PartTimeEmployee的对象（ 仅出于演示目的 ）。 现在，我想通过MessgaeContract调整SOAP消息。 我希望将请求对象称为EmployeeRequestObject，将响应对象称为EmployeeResponseObject，并且希望在其标头中包含相同的许可证密钥。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;

namespace EmployeeServiceLibrary
{
[ServiceContract]
public interface IEmployeeService
{
    [OperationContract]
    EmployeeResponse GetEmployee(EmployeeRequest request);
}

#region EmployeeRequestObject

[MessageContract(IsWrapped=true,WrapperName="EmployeeRequestObject",WrapperNamespace="http://Chiranjib_VAIO.com/")]
public class EmployeeRequest
{
    [MessageBodyMember(Namespace = "http://Chiranjib_VAIO.com/")]
    public int EmployeeRequestID { get; set; }

    [MessageHeader(Namespace = "http://Chiranjib_VAIO.com/")]
    public string EmployeeRequestLicenseKey { get; set; }
}
#endregion

#region EmployeeResponseObject
public class EmployeeResponse
{
    public EmployeeResponse()
    {
    }

    public EmployeeResponse(EmployeeRequest e)
    {
        this.EmployeeResponseLicenseKey = e.EmployeeRequestLicenseKey+"_Response";
    }

    [MessageHeader(Namespace = "http://Chiranjib_VAIO.com/")]
    public string EmployeeResponseLicenseKey { get; set; }
}
#endregion

[KnownType(typeof(FullTimeEmployee))]
[KnownType(typeof(PartTimeEmployee))]
[DataContract]
public abstract class Employee
{
    [DataMember]
    public int EmployeeId { get; set; }

    [DataMember]
    public string Name { get; set; }

    [DataMember]
    public string Gender { get; set; }

    [DataMember]
    public EmployeeType EmpType { get; set; }
}

public enum EmployeeType
{
    FullTimeEmployee=0,
    PartTimeEmployee=1
}

[DataContract]
public class FullTimeEmployee : Employee
{
    [DataMember]
    public decimal AnnualSalary { get; set; }
}

[DataContract]
public class PartTimeEmployee : Employee
{
    [DataMember]
    public int HoursWorked { get; set; }

    [DataMember]
    public decimal SalaryPerHour { get; set; }
}
}

当用户输入0时，我希望返回FullTimeEmployee对象，而当输入1时，我希望返回PartTimeEmployee对象。 这是服务文件

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;

namespace EmployeeServiceLibrary
{
public class EmployeeService : IEmployeeService
{
    public EmployeeResponse GetEmployee(EmployeeRequest request)
    {
        int empId = request.EmployeeRequestID;
        switch (empId)
        {
            case 0:
                return new FullTimeEmployee()
                {
                    EmployeeId=1,
                    Name="Chiranjib Nandy",
                    Gender="Male",
                    EmpType=EmployeeType.FullTimeEmployee,
                    AnnualSalary=1500
                };
            case 1:
                return new PartTimeEmployee()
                {
                    EmployeeId = 1,
                    Name = "Archana Nandy",
                    Gender = "Female",
                    EmpType = EmployeeType.PartTimeEmployee,
                    HoursWorked=9,
                    SalaryPerHour=150
                };
            default: return null;
        }
    }
}

}

但是错误是说不能将EmployeeServiceLibrary.FullTimeEmployee隐式转换为EmployeeServiceLibrary.EmployeeResponse。 如何实现预期的行为？ 帮助非常赞赏！ 谢谢

Answer 1

您的代码不会编译，因为两种返回类型都实现Employee ，而不是EmployeeResponse 。 您可以将Employee对象封装在EmployeeResponse

public class EmployeeResponse
{
   public EmployeeResponse(EmployeeRequest e)
   {
       this.EmployeeResponseLicenseKey = e.EmployeeRequestLicenseKey+"_Response";
   }

   [MessageHeader(Namespace = "http://Chiranjib_VAIO.com/")]
   public string EmployeeResponseLicenseKey { get; set; }

   public Employee Employee { get; set; }
}

然后将您的代码修改为：

public EmployeeResponse GetEmployee(EmployeeRequest request)
{
    int empId = request.EmployeeRequestID;
    switch (empId)
    {
        case 0:
            return new EmployeeResponse
            {
               Employee = new FullTimeEmployee()
               {
                 EmployeeId=1,
                 Name="Chiranjib Nandy",
                 Gender="Male",
                 EmpType=EmployeeType.FullTimeEmployee,
                 AnnualSalary=1500
               }
            }
        case 1:
            return new EmployeeResponse
            {
               Employee = new PartTimeEmployee()
               {
                  EmployeeId = 1,
                  Name = "Archana Nandy",
                  Gender = "Female",
                  EmpType = EmployeeType.PartTimeEmployee,
                  HoursWorked=9,
                  SalaryPerHour=150
               }
            }

        default: return null;
}