如何使用C＃WCF RESTful（即Web）服务发送CSV文件？

Question

我的任务是使用C＃WCF RESTful（即Web）服务以CSV格式发送数据。目前，我已设置代码以JSON发送数据。

如何以CSV格式发送数据？

注意：这实际上不是我正在使用的文件集。这只是一个示例，显示了我如何构建服务并帮助修改服务以生成CSV输出。

IService1.cs：

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

namespace WcfService4
{
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IService1" in both code and config file together.
    [ServiceContract]
    public interface IService1
    {
        [OperationContract]
        [WebInvoke(
            Method = "GET", 
            UriTemplate = "employees",
            RequestFormat = WebMessageFormat.Json,
            ResponseFormat = WebMessageFormat.Json,
            BodyStyle = WebMessageBodyStyle.Bare)]
        List<Employee> GetEmployees();
    }

    // Use a data contract as illustrated in the sample below to add composite types to service operations.
    [DataContract]
    public class Employee
    {
        [DataMember]
        public string FirstName { get; set; }

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

        [DataMember]
        public int Age { get; set; }

        public Employee(string firstName, string lastName, int age)
        {
            this.FirstName = firstName;
            this.LastName = lastName;
            this.Age = age;
        }
    }
}

Service1.svc.cs：

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

namespace WcfService4
{
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "Service1" in code, svc and config file together.
    public class Service1 : IService1
    {
        public List<Employee> GetEmployees()
        {
            // In reality, I'm calling the data from an external datasource, returning data to the client that exceeds 10 MB and can reach an upper limit of at least 30 MB.               

            List<Employee> employee = new List<Employee>();
            employee.Add(new Employee("John", "Smith", 28));
            employee.Add(new Employee("Jane", "Fonda", 42));
            employee.Add(new Employee("Brett", "Hume", 56));

            return employee;
        }
    }
}

Answer 1

有两种选择可以做到这一点。首先是编写的新实现，该实现IDispatchMessageFormatter知道如何理解CSV文件并将其“反序列化”为适当的类型。您可以在http://blogs.msdn.com/b/carlosfigueira/archive/2011/05/03/wcf-extensibility-message-formatters.aspx中找到有关它的更多信息。

另一种更为简单的方法是使用“原始编程模型”，在该模型中，您的操作返回类型被声明为Stream，并且您的操作可以返回CSV格式的数据。您可以在http://blogs.msdn.com/b/carlosfigueira/archive/2008/04/17/wcf-raw-programming-model-web.aspx上找到有关该模式的更多信息。