winform动态调用WebService

winform动态调用WebService，第一次接触，好多不理解啊，先把功能实现。。。。也希望懂的大神，讲解讲解。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.IO;
using System.Web.Services.Description;
using System.CodeDom;
using System.CodeDom.Compiler;
using Microsoft.CSharp;
using System.Collections;


namespace T7_Dynamic_WebService
{
    public partial class Form1 : Form
    {
        string _cityName = "";

        public Form1()
        {
            InitializeComponent();
           
        }

        private void btn_Search_Click(object sender, EventArgs e)
        {
            _cityName = tb01.Text.Trim();
            if (!string.Is