How to define global variables in C # and use global variables in each form

using system;using system.collections.generic;using System.Drawing;using System.windows.forms;using system.io;namespace Newtest{public class Publicvalue{public static string FileName;public static int[] AA; <summary>///Description of mainform.///</summary>public partial class Mainform:form{public mainform ()  {////the InitializeComponent () call was required for Windows Forms designer Support.//initializecomponent ();////Todo:add Constructor code after the InitializeComponent () call.//}void Mainformload (object sender, EventArgs e) {this. Width=screen.primaryscreen.workingarea.width;this. Height =screen.primaryscreen.workingarea.height;this. Left =screen.primaryscreen.workingarea.left;this. Top =screen.primaryscreen.workingarea.top;} void Button1Click (object sender, EventArgs e) {publicvalue.aa=new int[10]; publicvalue.aa[0]=10; Publicvalue.filename= "DFJLKJKLDFSJL";}}} 

The Publicvalue class defined above, where variables can be used in the same namespace, including in subforms or non-child windows.

How to define global variables in C # and use global variables in each form