delphi.net开发学习笔记（2），Application、Session、ViewState、Cookies状态以及变量处理

 代码例子：

//-----------------------------------------------------------------//  Application//-----------------------------------------------------------------procedure TWebForm1.Page_Load(sender: System.Object; e: System.EventArgs);begin  if Application[&apos;NumUsers&apos;] <> nil then    Label1.Text := &apos;Users visiting this site: &apos;+Application[&apos;NumUsers&apos;].ToString;end;procedure TGlobal.Session_Start(sender: System.Object; e: EventArgs);begin  Application.Lock;  try    if Application[&apos;NumUsers&apos;] = nil then      Application[&apos;NumUsers&apos;] := System.Object(Integer(1))    else      Application[&apos;NumUsers&apos;] :=        System.Object(Integer(Application[&apos;NumUsers&apos;])+1);  finally    Application.UnLock;  end;end;procedure TGlobal.Session_End(sender: System.Object; e: EventArgs);begin  Application.Lock;  try    if Application[&apos;NumUsers&apos;] <> nil then      Application[&apos;NumUsers&apos;] :=        System.Object(Integer(Application[&apos;NumUsers&apos;])-1)   else      Application[&apos;NumUsers&apos;] := System.Object(Integer(0));  finally    Application.UnLock;  end;end;//-----------------------------------------------------------------//  Session//-----------------------------------------------------------------procedure TWebForm1.Button1_Click(sender: System.Object; e: System.EventArgs);begin  Session.Add(&apos;UserName&apos;, TextBox1.Text);  Response.Redirect(&apos;WebForm2.aspx&apos;);end;//-----------------------------------------------------------------//  ViewState//-----------------------------------------------------------------procedure TWebForm1.Page_Load(sender: System.Object; e: System.EventArgs);begin  ViewState.Add(&apos;MyData&apos;, &apos;MyDataText&apos;);  Response.Write(ViewState[&apos;MyData&apos;]);end;//-----------------------------------------------------------------//  Cookies//-----------------------------------------------------------------procedure TWebForm1.Page_Load(sender: System.Object; e: System.EventArgs);begin  if not IsPostBack then    if not Request.Browser.Cookies then      lblNoCookie.Text := &apos;Your browser does not support cookies.&apos;    else begin      if Request.Cookies[&apos;MyName&apos;] <> nil then      begin        lblWelcome.Text := System.String.Format(&apos;Welcome back {0}&apos;,          Request.Cookies[&apos;MyName&apos;].Value);        TextBox1.Text := Request.Cookies[&apos;MyName&apos;].Value;      end;    end;end;