WinForm如何调用Web Service

1、建立项目WebService和WinForm项目，这里起名为WinFormInvokeWebService.
如图所示:

2、Service1.asmx代码为：（这部分其实和上篇的代码是一样的） 
 

using System;
using System.Collections.Generic;
using System.Web.Services;
using System.Data;
namespace WebService1
{
    /// <summary>
    /// Service1 的摘要说明
    /// </summary>
    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // 若要允许使用 ASP.NET AJAX 从脚本中调用此 Web 服务，请取消对下行的注释。
    [System.Web.Script.Services.ScriptService]
    public class Service1 : System.Web.Services.WebService
    {
        //无参方法
        [WebMethod]
        public string HelloWorld()
        {
            return "Hello World";
        }

        //有参方法1
        [WebMethod]
        public int Add(int a, int b)
        {
            return a + b;
        }

        //有参方法2
        [WebMethod]
        public int Sum(int x)
        {
            int sum = 0;
            for (int i = 0; i <= x; i++)
            {
                sum += i;
            }
            return sum;
        }

        // 返回一个复合类型
        [WebMethod]
        public Student GetStudentByStuNo(string stuNo)
        {
            if (stuNo == "001")
                return new Student { StuNo = "001", StuName = "张三" };
            if (stuNo == "002")
                return new Student { StuNo = "002", StuName = "李四" };
            return null;
        }

        //返回返回泛型集合的
        [WebMethod]
        public List<Student> GetList()
        {
            List<Student> list = new List<Student>();
            list.Add(new Student() { StuNo = "001", StuName = "张三" });
            list.Add(new Student() { StuNo = "002", StuName = "李四" });
            list.Add(new Student() { StuNo = "003", StuName = "王五" });
            return list;
        }

        //返回DataSet
        [WebMethod]
        public DataSet GetDataSet()
        {
            DataSet ds = new DataSet();
            DataTable dt = new DataTable();
            dt.Columns.Add("StuNo", Type.GetType("System.String"));
            dt.Columns.Add("StuName", Type.GetType("System.String"));