In ASP.NET, the term "global" typically refers to elements or settings that are accessible and applicable throughout an entire web application. This can include global variables, application-wide settings, and global events. Let's break it down with an example:
Example: Using Global.asax for Application Events
One common use of the term "global" in ASP.NET is with the Global.asax file. This file allows you to define application-level events and handlers that execute in response to application-wide events, such as application start, end, session start, and session end.
Here's a simple example:
Create a Global.asax File: In your ASP.NET project, add a Global.asax file if one doesn't already exist.
Define Application Events: Inside the Global.asax file, you can define event handler methods for various application events. For example:
Example
<%@ Application Language="C#" %>
<script runat="server">
void Application_Start(object sender, EventArgs e)
{
// Code that runs on application startup
Application["TotalVisitors"] = 0;
}
void Session_Start(object sender, EventArgs e)
{
// Code that runs when a new session is started
Application.Lock();
Application["TotalVisitors"] = (int)Application["TotalVisitors"] + 1;
Application.UnLock();
}
void Application_End(object sender, EventArgs e)
{
// Code that runs on application shutdown
}
</script>
In this example:
Application_Start: This event occurs when the application starts. Here, we initialize a global variable (TotalVisitors) to keep track of the total number of visitors to the application.Session_Start: This event occurs when a new user session begins. We increment the TotalVisitors count each time a new session starts.Application_End: This event occurs when the application shuts down. You can perform cleanup tasks here if needed.TotalVisitors variable anywhere in your application by referencing Application["TotalVisitors"].By using the Global.asax file, you can handle application-wide events and maintain global state or settings that are accessible throughout your ASP.NET web application. This helps in managing application lifecycle events and sharing data across different parts of the application.