我们在传统的web程序当中比较头疼的一件事是屏幕的刷新感。虽然有server push的技术，但在ie中较难实现。现在webservice给了我们这样一个机会，大家都知道webservice是基于soap的，而soap是xml的应用，如果你曾经用过ms xml sdk3.0的话就会知道里面有个xmlhttp方法，其实在那时我们就已经可以用xmlhttp的方式替代form了，也是无刷新的，其实准确地说是局部刷新，下面我们来看一下怎样做，先做一个chat webservice, 首先来分析一下，一个聊天室应具备的两个要素人和消息，这样我们可以建立一个类型（记得我在以前说过类也是类型），它包含这样两个要素。 ///chatmessage.cs using system;
namespace chat { /// <summary> /// chatmessage类封装了两个string变量:userlists--用户列表，messages--要传递的信息 /// </summary> public class chatmessage { public string userlist, messages; } } 第二个我们要建立的是什么呢？一个聊天室应能存储在线成员的名字及访问时间 ///member.cs using system;
namespace chat { /// <summary> /// member类为每个聊天者封装了server端的变量 /// </summary> public class member { // 存储消息的队列 public string username, msgqueue; // 判断滞留事件以便踢人 public system.datetime lastaccesstime; // the constructor public member(string nickname) { this.username=nickname; this.lastaccesstime=datetime.now; } } }
接下来我们就应该做这个asmx了 ///chatwebservice.asmx using system; using system.collections; using system.componentmodel; using system.data; using system.diagnostics; using system.web; using system.web.services;
namespace chat { /// <summary> /// summary description for chatwebservice. /// </summary> [webservice (namespace = "http://localhost/chat/", description = "this service provides an chat service")] public class chatwebservice : system.web.services.webservice { public chatwebservice() { //codegen: this call is required by the asp.net web services designer initializecomponent(); }
#region component designer generated code /// <summary> /// required method for designer support - do not modify /// the contents of this method with the code editor. /// </summary> private void initializecomponent() { } #endregion
/// <summary> /// clean up any resources being used. /// </summary> protected override void dispose( bool disposing ) { }
[webmethod(description="接收用户名作为参数存储到application对象中")] public string login(string username) { // ascertain that all the registered chat participants are active checkmemberslist(); // synchronization lock application.lock(); // get the collection of keys for the application variables string[] members = application.allkeys; // are there any registered chat members? & the present request is for a unique nick name? if ((members.length>0)&&(array.indexof(members,username)>-1)) { throw new exception("该用户已存在！"); } // create a new member object for this participant member newmember = new member(username); // add this new member to the collectionof application level variables application.add(username, newmember); // synchronization unlock application.unlock(); // go and get the list of current chat participants and retrun the list return getmemberslist(); }
[webmethod(description="getmsg方法用用户名和消息为参数返回一个chatmessage对象，包括要传递的消息和用户列表")] public chatmessage xchangemsgs(string username, string msg) { // ascertain that all the registered chat participants are active checkmemberslist(); // synchronization lock application.lock(); // get the collection of keys for the application variables string[] members = application.allkeys; if ((members.length==0)||(array.indexof(members,username)==-1)) // are there any registered chat members? & the present request is for a unique nick name? { throw new exception("你当前可能没有登陆或登陆超时，请重新登陆！"); } chatmessage retmsg = new chatmessage();
retmsg.userlist = getmemberslist(); // loop through all the chat participant's serverside member objects and // add the message just received in their waiting message queue for (int x=0;x<members.length;x++) { member temp = (member)application[members[x]]; temp.msgqueue+=("<br><font color = red>" + username + " 说:<br></font><font color = blue>" + msg); if (temp.username == username) { retmsg.messages = temp.msgqueue; temp.msgqueue=""; temp.lastaccesstime=datetime.now; } } // synchronization unlock application.unlock(); return retmsg; }
[webmethod(description="getmsg方法用username为参数返回一个chatmessage对象，包括要传递的消息和用户列表")] public chatmessage getmsgs(string username) { application.lock(); checkmemberslist(); application.lock(); string[] members = application.allkeys; if ((members.length==0)||(array.indexof(members,username)==-1)) { throw new exception("unknown user. please login with a username"); } chatmessage retmsg = new chatmessage(); retmsg.userlist = getmemberslist(); member temp = (member)application[username]; retmsg.messages = temp.msgqueue; temp.msgqueue=""; temp.lastaccesstime=datetime.now; application.unlock(); return retmsg; }
public string getmemberslist() { application.lock(); string userlist = ""; string[] members = application.allkeys; application.unlock(); for (int x=0;x<members.length;x++) { member temp = (member)application[members[x]]; userlist += (temp.username+"/n"); } return userlist; }
private void checkmemberslist() { string[] members = application.allkeys; arraylist removelist = new arraylist(); for (int x=0;x<members.length;x++) { member temp = (member) application[members[x]]; int test = (datetime.now.subtract(temp.lastaccesstime)).minutes; if (test > 2) { removelist.add(members[x]); } } // users = null; for (int count = 0;count<removelist.count;count++) { application.remove((string)removelist[count]); } return; }
