Asp. NET of application detailed

Application in ASP . 1. Application is used to save information that is common to all users. In the ASP era, using application is an ideal choice if the data to be saved is not or rarely changed during the lifetime of the application. But in ASP. NET development environment, programmers usually put similar configuration data in the Web. config. If you want to use application, be aware that all write operations are done in the Application_OnStart event in the Global.asax file. The following code is set in the Global.asax file Application.Lock (); application["UserId"]= "Hello kitty"; Application.UnLock (); The following is a call to application in the page String userid=application["UserId"]. ToString (); 2, Application characteristics: 1. Information size is arbitrary size 2. Apply to entire application/all users 3. Save on server side 4. Scope and save time is the lifetime of the entire application 3. If you use the Application object in your application, one of the issues to consider is that any write operation is done in the Application_OnStart event in the global file. Although the Application.Lock () and Application.UnLock () methods are used to avoid synchronization, because of the serialization of requests to the Application object, there is a serious performance bottleneck when the Web site accesses a large amount of traffic. Therefore, it is best not to save large collections of data in this object. 4, the following use application to achieve online user statistics, record the number of people and total number of visitors to the site. usingSystem;usingSystem.Collections.Generic;usingSystem.Linq;usingsystem.web;usingSystem.ComponentModel;usingSystem.IO;usingSystem.Web.SessionState;/// <summary>///Summary description of Global/// </summary> Public classglobal:system.web.httpapplication{PrivateSystem.ComponentModel.IContainer component =NULL;//necessary designer Variables PrivateFileStream FileStream; PrivateStreamReader reader;//read stream of characters PrivateStreamWriter writer;//Write character Stream PublicGlobal () {}/// <summary> ///Website program Launch/// </summary> /// <param name= "Sender" ></param> /// <param name= "E" ></param> protected voidApplication_Start (ObjectSender,eventargs e) {application["CurrentUser"] =0;//Initializing online users//loads the file stream and creates a file if the file does not existFileStream=NewFileStream (Server.MapPath ("~/count.txt"), FileMode.OpenOrCreate); Reader=NewStreamReader (FileStream);//using streams to read filesapplication["AllUser"] = Convert.ToInt32 (reader. ReadLine ());//to deposit records from a file in the total number of accessesReader. Close ();//Close the stream } /// <summary> ///session start, when users visit the site, online users +1, total visits +1/// </summary> /// <param name= "Sender" ></param> /// <param name= "E" ></param> protected voidSession_Start (Objectsender, EventArgs e) {Application.Lock ();//lock to prevent simultaneous entryapplication["CurrentUser"] = (int) application["CurrentUser"] +1; application["AllUser"] = (int) application["AllUser"] +1; FileStream=NewFileStream (Server.MapPath ("~/count.txt"), FileMode.OpenOrCreate, FileAccess.Write); //Write Streamwriter=NewStreamWriter (FileStream); //Gross position access number is written to the Count.txt file againwriter. WriteLine (application["AllUser"]. ToString ()); Writer. Close ();//Close Write StreamApplication.UnLock ();//Unlock Lock } /// <summary> ///Session End/// </summary>

Asp. NET of application detailed