需求：内网公告牌能够正确显示未来三天的天气信息
本文关键字：C#/WebForm/Web定时任务/Ajax跨域
规划：
1、天定时读取百度接口获取天气信息并存储至Txt文档；
2、示牌开启时请求WebService，获取天气信息；
解决方案：
1、在Global.asax中能够配置整个工程不同情况下触发的事件，其中 Application_Start方法是在iis启动本项目时就开始的进程。在本方法下写入定时从百度读取天气信息的代码，调用的WebService代码在下面的第2部分：
protected void Application_Start(object sender, EventArgs e)
{
String NowTime = DateTime.Now.ToString("hh24:mi:ss");
//定时任务
//if (NowTime == "")
//{
WebService1 ws = new WebService1();
ws.GetBaiduWeather();
//}
//每天执行一次
Timer t = new Timer(60 * 60 * 24 * 1000);
t.Elapsed += new System.Timers.ElapsedEventHandler(DownLoadWeather);
t.Enabled = true; }
WebService代码如下
[WebMethod]
public void GetBaiduWeather()
{
string callback = HttpContext.Current.Request["jsoncallback"];
WeatherDownload.getrequest();
HttpContext.Current.Response.Write(callback +
"({result:'true'})");
HttpContext.Current.Response.End();
}
调用百度天气接口存储数据的代码如下所示，其存储的结果是Json字符串。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Net;
using System.IO;
using System.Text;
using System.Text.RegularExpressions; namespace WebService
{
public static class WeatherDownload
{
public static string url = "http://apis.baidu.com/apistore/weatherservice/recentweathers";
public static string param = "cityname=石家庄&cityid=101090101";
/// <summary>
/// 查询天气情况
/// </summary>
/// <param name="url"></param>
public static void getrequest()
{
string strURL = url + '?' + param;
System.Net.HttpWebRequest request;
request = (System.Net.HttpWebRequest)WebRequest.Create(strURL);
request.Method = "GET";
request.Headers.Add("apikey", "在百度上申请的开发者个人码");
System.Net.HttpWebResponse response;
response = (System.Net.HttpWebResponse)request.GetResponse();
System.IO.Stream s;
s = response.GetResponseStream();
string StrDate = "";
string strValue = "";
StreamReader Reader = new StreamReader(s, Encoding.UTF8);
while ((StrDate = Reader.ReadLine()) != null)
{
strValue += StrDate + "\r\n";
}
if (File.Exists(System.AppDomain.CurrentDomain.BaseDirectory + "\\" + DateTime.Now.ToString("yyyyMMdd") + ".txt"))
{
}
else
{
using (File.Create(System.AppDomain.CurrentDomain.BaseDirectory + "\\" + DateTime.Now.ToString("yyyyMMdd") + ".txt"))
{
}
}
FileStream fs = new FileStream(System.AppDomain.CurrentDomain.BaseDirectory + "\\" + DateTime.Now.ToString("yyyyMMdd") + ".txt", FileMode.Create);
StreamWriter sw = new StreamWriter(fs);
String w = UnicodeToStr(strValue);
sw.Write(w);
sw.Flush();
sw.Close();
fs.Close();
}
/// <summary>
/// 编码为汉字
/// </summary>
/// <param name="str"></param>
/// <returns></returns>
public static string UnicodeToStr(string str)
{
string outStr = "";
Regex reg = new Regex(@"(?i)\\u([0-9a-f]{4})");
outStr = reg.Replace(str, delegate(Match m1)
{
return ((char)Convert.ToInt32(m1.Groups[1].Value, 16)).ToString();
});
return outStr;
}
}
}
2、页面请求WebService获取天气数据
此处使用的Ajax请求，特征是跨域请求，当时出的问题比较多，一篇很好的参考文献如下（http://www@suchso@com/projecteactual/jquery-ajax-parsererror-was-not-called.html）（请把@改为.）
$.ajax({
//111.111.111.111为实际
url: "http://111.111.111.111/WebService1.asmx/GetWeather?jsoncallback=?",
dataType: "jsonp",
success: OnSuccess,
error: OnError
});
//}
function OnSuccess(json) {
$("#today").text(json.retData.today.curTemp.toString())
$("#today_wth").text(json.retData.today.type.toString())
}
function OnError(XMLHttpRequest, textStatus, errorThrown) {
alert("Something error");
}
对应的WebService代码如下
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.IO;
using System.Text;
namespace WebService
{
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.ComponentModel.ToolboxItem(false)]
public class WebService1 : System.Web.Services.WebService
{
[WebMethod]
public void GetWeather()
{
String sr = File.ReadAllText(System.AppDomain.CurrentDomain.BaseDirectory + DateTime.Now.ToString("yyyyMMdd") + ".txt", UnicodeEncoding.GetEncoding("UTF-8")); string callback = HttpContext.Current.Request["jsoncallback"];
HttpContext.Current.Response.Write(callback + "(" + sr + ")");
} }
}