What really is the purpose of “base” keyword in c#

Question

Thus for used base class for some commom reusable methods in every page of my application...

public class BaseClass:System.Web.UI.Page
{
   public string GetRandomPasswordUsingGUID(int length)
   {
      string guidResult = System.Guid.NewGuid().ToString();
      guidResult = guidResult.Replace("-", string.Empty);
      return guidResult.Substring(0, length);
   }
}

So if i want to use this method i would just do,

public partial class forms_age_group : BaseClass
{
      protected void Page_Load(object sender, EventArgs e)
      {
            //i would just call it like this
            string pass = GetRandomPasswordUsingGUID(10);
      }
}

It does what i want but there is a "Base" keyword that deals with base class in c# ... I really want to know when should use base keyword in my derived class....

Any good example...

Answer 1

The base keyword is used to access members in the base class that have been overridden (or hidden) by members in the subclass.

For example:

public class Foo
{
    public virtual void Baz()
    {
        Console.WriteLine("Foo.Baz");
    }
}

public class Bar : Foo
{
    public override void Baz()
    {
        Console.WriteLine("Bar.Baz");
    }

    public override void Test()
    {
        base.Baz();
        Baz();
    }
}

Calling Bar.Test would then output:

Foo.Baz;
Bar.Baz;

Answer 2

You will use base keyword when you override a functionality but still want the overridden functionality to occur also.

example:

 public class Car
 {
     public virtual bool DetectHit() 
     { 
         detect if car bumped
         if bumped then activate airbag 
     }
 }


 public class SmartCar : Car
 {
     public override bool DetectHit()
     {
         bool isHit = base.DetectHit();

         if (isHit) { send sms and gps location to family and rescuer }

         // so the deriver of this smart car 
         // can still get the hit detection information
         return isHit; 
     }
 }


 public sealed class SafeCar : SmartCar
 {
     public override bool DetectHit()
     {
         bool isHit = base.DetectHit();

         if (isHit) { stop the engine }

         return isHit;
     }
 }