ASP.NET - States - Application

Application state in ASP.NET is a server-side state management mechanism that allows you to store data that can be accessed across all users and sessions of an application. The data stored in application state is available throughout the lifetime of an application.

Application state can be useful for storing application-level settings, counters, and other data that needs to be shared across all users of an application. Application state is stored in a dictionary-like object called the Application object, which is a property of the HttpApplication class. The Application object can be accessed from anywhere in your application code.

Here is an example of using application state in ASP.NET:

Let's say you want to keep track of the number of times a particular page has been viewed by all users of your application. You can use application state to store a counter that increments every time the page is viewed.

First, you need to create a global counter variable in the Application_Start method in the Global.asax file:

void Application_Start(object sender, EventArgs e) 
{
    // Code that runs on application startup
    Application["PageViews"] = 0;
}

This will initialize the counter to 0 when the application starts.

Next, you can increment the counter in the Page_Load method of the page:

void Page_Load(object sender, EventArgs e) 
{
    // Code that runs when the page is loaded
    int pageViews = Convert.ToInt32(Application["PageViews"]);
    pageViews++;
    Application["PageViews"] = pageViews;
}

This code retrieves the current value of the counter from the Application object, increments it, and then stores the new value back in the Application object.

Finally, you can display the current value of the counter on the page:

<p>This page has been viewed <%# Application["PageViews"] %> times.</p>

This will display the current value of the counter on the page.

In this example, we are using application state to store a counter that tracks the number of times a page has been viewed. This counter is shared across all users of the application and is stored in the Application object.