Global variables in c#.net

Solution 1:

Use a public static class and access it from anywhere.

public static class MyGlobals {
    public const string Prefix = "ID_"; // cannot change
    public static int Total = 5; // can change because not const
}

used like so, from master page or anywhere:

string strStuff = MyGlobals.Prefix + "something";
textBox1.Text = "total of " + MyGlobals.Total.ToString();

You don't need to make an instance of the class; in fact you can't because it's static. new Just use it directly. All members inside a static class must also be static. The string Prefix isn't marked static because const is implicitly static by nature.

The static class can be anywhere in your project. It doesn't have to be part of Global.asax or any particular page because it's "global" (or at least as close as we can get to that concept in object-oriented terms.)

You can make as many static classes as you like and name them whatever you want.

Sometimes programmers like to group their constants by using nested static classes. For example,

public static class Globals {
    public static class DbProcedures {
        public const string Sp_Get_Addresses = "dbo.[Get_Addresses]";
        public const string Sp_Get_Names = "dbo.[Get_First_Names]";
    }
    public static class Commands {
        public const string Go = "go";
        public const string SubmitPage = "submit_now";
    }
}

and access them like so:

MyDbCommand proc = new MyDbCommand( Globals.DbProcedures.Sp_Get_Addresses );
proc.Execute();
//or
string strCommand = Globals.Commands.Go;

Solution 2:

I second jdk's answer: any public static member of any class of your application can be considered as a "global variable".

However, do note that this is an ASP.NET application, and as such, it's a multi-threaded context for your global variables. Therefore, you should use some locking mechanism when you update and/or read the data to/from these variables. Otherwise, you might get your data in a corrupted state.

Solution 3:

You can create a base class in your application that inherits from System.Web.UI.Page. Let all your pages inherit from the newly created base class. Add a property or a variable to your base class with propected access modifier, so that it will be accessed from all your pages in the application.