常见.NET功能代码汇总

23,获取和装置分级缓存

博缓存:首先从当地缓存获取,如果无,再夺读取分布式缓存
描绘缓存:同时写本地缓存和分布式缓存

  private static T GetGradeCache<T>(string key) where T:struct 
        {
            MemoryCacheManager localCache = MemoryCacheManager.Instance;
            if (!localCache.IsSet(key))
            {
                //本地不存在此缓存
               T  remoteValue = MemCacheManager.Instance.Get<T>(key);
               if (!ValueType.Equals(remoteValue, default(T)))
               { 
                    //如果远程有
                   localCache.Set(key, remoteValue, 1); 
               }
               else
               {
                   localCache.SetFromSeconds(key, default(T), 10); 
               }
               return remoteValue;
            }
            T value = localCache.Get<T>(key);
            return value;
        }

        private static void SetGradeCache<T>(string key,T Value,int time) where T : struct 
        {
            MemoryCacheManager localCache = MemoryCacheManager.Instance;
            localCache.Remove(key);
            localCache.Set(key, Value, time);
            MemCacheManager.Instance.Remove(key);
            MemCacheManager.Instance.Set(key, Value, time); 
        }

24,求相对目录的绝对路径

突发性,我们需要要求相对于当下清目录的相对目录,比如以日志文件存储于站点目录以外,我们得以
../logs/ 的办法:

 string vfileName = string.Format("../logs/{0}_{1}_{2}.log", logFileName, System.Environment.MachineName, DateTime.Now.ToString("yyyyMMdd"));
            string rootPath = HttpContext.Current.Server.MapPath("/");
            string targetPath = System.IO.Path.Combine(rootPath, vfileName);
            string fileName = System.IO.Path.GetFullPath(targetPath);
            string fileDir = System.IO.Path.GetDirectoryName(fileName);
            if (!System.IO.Directory.Exists(fileDir))
                System.IO.Directory.CreateDirectory(fileDir);

斯代码会当站点目录外的日记目录,建立一个
代机器名称的按日期区分的日志文件。

25,多次尝试写日记文件措施

日志文件或者会见产出的写入,此时恐怕会见唤起“文件于另外一个经过占用”,因此可频繁品写入。下面的方法会递归的开展文件写副尝试,如果尝试次数用了才见面最后报错。

  /// <summary>
        /// 保存日志文件
        /// </summary>
        /// <param name="logFileName">不带扩展名文件名</param>
        /// <param name="logText">日志内容</param>
        /// <param name="tryCount">如果出错的尝试次数,建议不大于100,如果是0则不尝试</param>
        public static void SaveLog(string logFileName, string logText, int tryCount)
        {
            string vfileName = string.Format("..\\logs\\{0}_{1}_{2}.log", logFileName, System.Environment.MachineName, DateTime.Now.ToString("yyyyMMdd"));
            string rootPath = System.AppDomain.CurrentDomain.BaseDirectory;
            string targetPath = System.IO.Path.Combine(rootPath, vfileName);
            string fileName = System.IO.Path.GetFullPath(targetPath);
            string fileDir = System.IO.Path.GetDirectoryName(fileName);
            if (!System.IO.Directory.Exists(fileDir))
                System.IO.Directory.CreateDirectory(fileDir);

            try
            {
                System.IO.File.AppendAllText(fileName, logText);
                tryCount = 0;
            }
            catch (Exception ex)
            {
                if (tryCount > 0)
                {
                    System.Threading.Thread.Sleep(1000);
                    logText = logText + "\r\nSaveLog,try again times =" + tryCount + " ,Error:" + ex.Message;
                    tryCount--;
                    SaveLog(logFileName, logText, tryCount);
                }
                else
                {
                    throw new Exception("Save log file Error,try count more times!");
                }
            }
        }

 26,ASP.NET获取客户端的IP地址

      string GetRemoteIP()
        {
            string result = HttpContext.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
            if (null == result || result == String.Empty)
            {
                result = HttpContext.Request.ServerVariables["REMOTE_ADDR"];
            }


            if (null == result || result == String.Empty)
            {
                result = HttpContext.Request.UserHostAddress;
            }
            return result;

27,ASP.NET MVC 在Action里面得到请求的URL

足划分吧3种艺术,
1)ASP.NET MVC 在控制器的默认Action里面得到请求其它Action的门道
依照在默认的 Index Action里面得到路径,如下:

string sso_url= "http://" + Request.Url.Authority + Request.Url.AbsolutePath + "/SSO?id=" + userid;

 2)在外Action里面得到当前控制器的路径 

string ctrName = RouteData.Values["controller"].ToString();
 string redirectUrl = "http://" + Request.Url.Authority + "/" + ctrName + "/SSO?id=" + userid;

 3)直接沾当前Action请求的路径

string url=Request.Url.ToString();

 

28,ASP.NET MVC Action返回可以在浏览器直接翻的纯文本信息

需指定Context的contentType 为“text/plain”,代码如下:

 public ActionResult SendMessage()
 {
   string txt="你好!";
   return Content(text, "text/plain", System.Text.Encoding.UTF8);
  }

 29,使用Linq2XML读写XML

此间关键行使XDocument,XElement对象来操作XML内容,如下代码:

    public static class XDocumentExtentsion
    {
        //生成XML的申明部分
        public static string ToStringWithDeclaration(this XDocument doc, SaveOptions options = SaveOptions.DisableFormatting)
        {
            return doc.Declaration.ToString() + doc.ToString(options);
        }
    }

        public string CreateMsgResult(string loginUserId,string corpid, string msg,string ts)
        {
            var xDoc = new XDocument(
                new XDeclaration("1.0", "UTF-8", null),  
                new XElement("result",
                    new XElement("corpid", corpid),
                    new XElement("userid", loginUserId),
                    new XElement("ts", ts),
                    new XElement("sendmsg", msg)
                ));
            return xDoc.ToStringWithDeclaration();
        }

        public ResponseMessage ParseXMLString(string xml)
        {
            var xDoc = XDocument.Parse(xml);
            if (xDoc == null) return null;
            var root = xDoc.Element("result");
            if(root==null)
                throw new Exception ("not found the 'result' root node,input XML\r\n"+xml);
            ResponseMessage result =
             new ResponseMessage()
             {
                 ErrorCode  = root.Element("rescode").Value,
                 ErrorMessage  = root.Element("resmsg").Value,
                 RedirectUrl  = root.Element("redirect_url") == null ? "" : root.Element("redirect_url").Value
             };

            return result;
        }

 30,访问Web内容的自定义代码

采用 HttpWebRequest和HttpWebResponse 对象就Web访问,如果是.NET
4.5,建议直接运用 HttpClient对象:

        /// <summary>
        /// 获取请求结果
        /// </summary>
        /// <param name="requestUrl">请求地址</param>
        /// <param name="timeout">超时时间(秒)</param>
        /// <param name="requestXML">请求xml内容</param>
        /// <param name="isPost">是否post提交</param>
        /// <param name="encoding">编码格式 例如:utf-8</param>
        /// <param name="errorMsg">抛出的错误信息</param>
        /// <returns>返回请求结果</returns>
        public static string HttpWebRequest(string requestUrl, int timeout, string requestXML, bool isPost, string encoding, out string errorMsg, string contentType = "application/x-www-form-urlencoded")
        {
            errorMsg = string.Empty;
            string result = string.Empty;
            try
            {
                byte[] bytes = System.Text.Encoding.GetEncoding(encoding).GetBytes(requestXML);
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(requestUrl);
                request.Referer = requestUrl;
                request.Method = isPost ? "POST" : "GET";
                request.Timeout = timeout * 1000;
                if (isPost)
                {
                    request.ContentType = contentType;// "application/x-www-form-urlencoded";
                    request.ContentLength = bytes.Length;
                    using (Stream requestStream = request.GetRequestStream())
                    {
                        requestStream.Write(bytes, 0, bytes.Length);
                        requestStream.Close();
                    }
                }

                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                Stream responseStream = response.GetResponseStream();
                if (responseStream != null)
                {
                    StreamReader reader = new StreamReader(responseStream, System.Text.Encoding.GetEncoding(encoding));
                    result = reader.ReadToEnd();
                    reader.Close();
                    responseStream.Close();
                    request.Abort();
                    response.Close();
                    return result.Trim();
                }
            }
            catch (Exception ex)
            {
                errorMsg =string.Format("Error Message:{0},Request Url:{1},StackTrace:{2}", ex.Message ,requestUrl , ex.StackTrace);
            }

            return result;
        }

 31,自定义浏览器协议(伪协议),实现web程序调用本地程序

(转自 http://blog.sina.com.cn/s/blog_4a77f0630100hav3.html)
新近种遇到这么个问题。客户要求用web页面,点击一个链接,调用本地的一个主次。

参考了瞬间qq的点子。
tencent://Message/?Uin=000000&websiteName=qzone.qq.com&Menu=yes

每当注册表里面添加下面,就能够实现,详细内容见原文

 

32,线程安全的通向集合添加元素

偶尔,向一个List对象调用Add
方法,会起“索引超出了反复组界限”这样的问题,此时足考虑以线程安全的集结,但于事情及设定了集的最特别价值的情下,用线程安全集合就出接触再次了,效率不愈,此时足通过
Interlocked.CompareExchange 来实现,具体代码如下:

private int length=0;
private int maxLength=50;
private int[] Arr=new int[maxLength];

//使用循环数组,安全的添加元素
void Add(int value){
  int p= Interlocked.CompareExchange(ref length,0,maxLength);
  if(p==length) 
  {
      //说明length变量并且没有达到最大值,并安全的返回length当时的值
      Arr[p]=value;
  }
  else
  {
      //数组元素已经达到上限,需要触发另外的操作,比如将数组全部输出
      // To Do
      //之后,再将当前位置的元素写入
      //此时,length可能是0,也可能是其它值
      Arr[length]=value;
  }
  Interlocked.Increment(ref length);
}

 

 33,WPF绑定异步更新的多少集合

日前举行一个WPF项目,后端API推送过来的数目如果更新WPF界面的数目,发现有点数据尚未跟后端数据状态一样。通常情况下,WPF绑定的Model数据集合都是继往开来于ObservableCollection
的,但是当当前情况下会发出题目,这是得打包一个异步的数量集合:

public class AsyncObservableCollection<T> : ObservableCollection<T>
{
    //获取当前线程的SynchronizationContext对象
    private SynchronizationContext _synchronizationContext = SynchronizationContext.Current;
    public AsyncObservableCollection() { }
    public AsyncObservableCollection(IEnumerable<T> list) : base(list) { }
    protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
    {

        if (SynchronizationContext.Current == _synchronizationContext)
        {
            //如果操作发生在同一个线程中,不需要进行跨线程执行         
            RaiseCollectionChanged(e);
        }
        else
        {
            //如果不是发生在同一个线程中
            //准确说来,这里是在一个非UI线程中,需要进行UI的更新所进行的操作         
            _synchronizationContext.Post(RaiseCollectionChanged, e);
        }
    }
    private void RaiseCollectionChanged(object param)
    {
        // 执行         
        base.OnCollectionChanged((NotifyCollectionChangedEventArgs)param);
    }
    protected override void OnPropertyChanged(PropertyChangedEventArgs e)
    {
        if (SynchronizationContext.Current == _synchronizationContext)
        {
            // Execute the PropertyChanged event on the current thread             
            RaisePropertyChanged(e);
        }
        else
        {
            // Post the PropertyChanged event on the creator thread             
            _synchronizationContext.Post(RaisePropertyChanged, e);
        }
    }
    private void RaisePropertyChanged(object param)
    {
        // We are in the creator thread, call the base implementation directly         
        base.OnPropertyChanged((PropertyChangedEventArgs)param);
    }
}

再多信息,请参考:

WPF多线程UI更新——两栽艺术

绑定XML到异步的ObservableCollection

 

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