protected void Application_Start(Object sender, EventArgs e) ...{
Application["Title"] = "Builder.com Sample";
}
protected void Session_Start(Object sender, EventArgs e) ...{
Session["startValue"] = 0;
}
protected void Application_AuthenticateRequest(Object sender, EventArgs e) ...{
// Extract the forms authentication cookie 
string cookieName = FormsAuthentication.FormsCookieName;
HttpCookie authCookie = Context.Request.Cookies[cookieName];
if(null == authCookie) ...{
// There is no authentication cookie. 
return;
}
FormsAuthenticationTicket authTicket = null;
try ...{
authTicket = FormsAuthentication.Decrypt(authCookie.Value);
} catch(Exception ex) ...{
// Log exception details (omitted for simplicity) 
return;
}
if (null == authTicket) ...{
// Cookie failed to decrypt. 
return;
}
// When the ticket was created, the UserData property was assigned
// a pipe delimited string of role names. 
string[2] roles
roles[0] = "One"
roles[1] = "Two"
// Create an Identity object 
FormsIdentity id = new FormsIdentity( authTicket );
// This principal will flow throughout the request. 
GenericPrincipal principal = new GenericPrincipal(id, roles);
// Attach the new principal object to the current HttpContext object 
Context.User = principal;
}
protected void Application_Error(Object sender, EventArgs e) ...{
Response.Write("Error encountered.");
}

    这个例子只是很简单地使用了一些Global.asax 文件中的事件；重要的是要意识到这些事件是与整个应用程序相关的。这样，所有放在其中的方法都会通过应用程序的代码被提供，这就是它的名字为Global 的原因。

    这里是前面的例子相应的 VB.NET 代码：

Sub Application_Start()Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)
Application("Title") = "Builder.com Sample"
End Sub
Sub Session_Start()Sub Session_Start(ByVal sender As Object, ByVal e As EventArgs)
Session("startValue") = 0
End Sub
Sub Application_AuthenticateRequest()Sub Application_AuthenticateRequest(ByVal sender As Object, ByVal e As
 EventArgs)
' Extract the forms authentication cookie 
Dim cookieName As String
cookieName = FormsAuthentication.FormsCookieName
Dim authCookie As HttpCookie
authCookie = Context.Request.Cookies(cookieName)
If (authCookie Is Nothing) Then
' There is no authentication cookie. 
Return
End If
Dim authTicket As FormsAuthenticationTicket
authTicket = Nothing
Try
authTicket = FormsAuthentication.Decrypt(authCookie.Value)
Catch ex As Exception
' Log exception details (omitted for simplicity) 
Return
End Try
Dim roles(2) As String
roles(0) = "One"
roles(1) = "Two"
Dim id As FormsIdentity
id = New FormsIdentity(authTicket)
Dim principal As GenericPrincipal
principal = New GenericPrincipal(id, roles)
' Attach the new principal object to the current HttpContext object 
Context.User = principal
End Sub
Sub Application_Error()Sub Application_Error(ByVal sender As Object, ByVal e As EventArgs)
Response.Write("Error encountered.")
End Sub

     资源

    Global.asax 文件是 ASP.NET 应用程序的中心点。它提供无数的事件来处理不同的应用程序级任务，比如用户身份验证、应用程序启动以及处理用户会话等。你应该熟悉这个可选文件，这样就可以构建出健壮的ASP.NET 应用程序。