static variables

[nightscorpion]

hi everyone ,
Im having problems in saving values in the static variables. Here it is how it goes
i have 3 projects in a solution. Lets say A , B and C.
I have added the references of C in A and B
A calls C and saves a value .
Later B calls C but B get the value as 0(even though this variable wasnt used anywhere in between)
this is how my code looks like


A:

public   class Program 
    {
 static void Main(string[] args)
        {
...
...
 Mediator.Class1 mediat = new Mediator.Class1();
  mediat.test(4);
  waitHandle.WaitOne();
         }
   }

B:

...
...

 Mediator.Class1 mediat = new Mediator.Class1();
           mediat.recieveEle(request);

C:

 public   class Class1
    {
 public static int m_globalVar = 0;
int j;

     public static int GlobalVar
        {
            get { return m_globalVar; }
            set { m_globalVar = value; }
        }
 public void test( int i)
        {
         
            GlobalVar = i;
        }
        public void recieveEle(Element ele)
        {
            j = GlobalVar;

        }
    }

[MNovy]

You say you have a problem with saving values,
but you did not share the error message or the core problem with us.

What is exactly your problem?

[memeloo]

sounds like a homework...

[nightscorpion]

its not my homework.its a project on which im working on.n i guess there is a small mistake wht i have in this code which is actually getting to my nerves. The problem is the variable j gets the value 0 when the method recieveEle is called.

[MNovy]

well, there is no problem with the code.
Just look at the following again

in A:
 Mediator.Class1 mediat = new Mediator.Class1();

in B:
Mediator.Class1 mediat = new Mediator.Class1();

You just create two independent instances of your class. Surely the value you set in one instance is not set in the other one. They are independent.

[nelo]

its not my homework.its a project on which im working on.n i guess there is a small mistake wht i have in this code which is actually getting to my nerves. The problem is the variable j gets the value 0 when the method recieveEle is called.

Well...I'm not sure what the problem is. It seems to me that '0' is a valid value for GlobalVar. There is nothing in the sample to suggest that GlobalVar should have a different value when 'recieveEle' is called. If you think otherwise perhaps you could set up a break point in the setter (i.e. set { m_globalVar = value; }). You may need the [DebuggerStepThrough] attribute to do this. With the break point you will be able to see at what point GlobalVar is being set to '0' before 'recieveEle' is called.

[nightscorpion]

hmm.. ok
so wht other option do i have so that i can get the value of j=4?
or perhaps that i could capture the same instance in two classes?

when i set the breakpoint in B where the new instance is created , thats where j is set to 0

thank you

[MNovy]

when i set the breakpoint in B where the new instance is created , thats where j is set to 0

No wonder. You just access a different instance than the one in the main is set.

hmm.. ok
so wht other option do i have so that i can get the value of j=4?
or perhaps that i could capture the same instance in two classes?

1) you could create a static class, which needs no instances and is directly accessible from anywhere.

2) you could pass the instance from one class into other class (by using parameters) to use values there

[boudino]

But there is common static variable, which holds the value. It should work... hm...

Other idea: "j" is never declared in the example. What it is? Maybe you are inspecting other "j" than you think you set the value?

[nightscorpion]

hi ,

1) you could create a static class, which needs no instances and is directly accessible from anywhere.

yeah actually the static variable should be holding the value even though i have 2 instances.....well i cannot declare my class as static coz i would later also want to implement an interface .

2) you could pass the instance from one class into other class (by using parameters) to use values there

i do not have much expierence ..but can i know how can i pass the instance of one class to another by using parameters?


regarding j ..i had initialised it in my program. however i forgot to initialise it in my post..but now i have edited the code.

[MNovy]

Just study this code and you're fine.

A is some basic class.
B just get all values from A passed and can be used independently. Changes in B do not affect A.
C gets a references on A. Everything changed in C, is changed also in A.

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            A myClass_A_in_Main = new A();     // create instance of A
            myClass_A_in_Main.variable = 5;    // set value in that instance
            myClass_A_in_Main.Display_Value(); // display value from that instance

            B myClass_B_in_Main = new B(myClass_A_in_Main); // create new instance of B, pass A, copy values
            myClass_B_in_Main.Display_Value();              // Display value in other instance


            C myClass_C_in_Main = new C();
            myClass_C_in_Main.DoSomething(ref myClass_A_in_Main);  // change referenced value
            myClass_A_in_Main.Display_Value();                 // display value from that instance


            Console.Read();

        }
    }


    /// <summary>
    /// Simple Class with display method.
    /// </summary>
    class A
    {
        public int variable;
        public void Display_Value()
        {
            Console.WriteLine(variable);
        }
    }


    /// <summary>
    /// This Class holds the other class A inside. The values are passed through constructor
    /// </summary>
    class B
    {
        A myClass_A_in_B = new A();

        public B(A getInstance) // Constructor with input parameter
        {
            myClass_A_in_B = getInstance; // copy values if new instance is created
        }

        public void Display_Value()
        {
            Console.WriteLine(myClass_A_in_B.variable);
        }
    }



    /// <summary>
    /// This Class get only a reference on another Class. Changes here affects the other class, too.
    /// </summary>
    class C
    {
        public void DoSomething(ref A referencedA)
        {
            referencedA.variable = 999;
            referencedA.Display_Value();
        }
    }

}

[memeloo]

I think this code is wrong because A, B and C are not classes but projects, so they are assemblies: A is an exe and B&C are dlls I guess

[nightscorpion]

yes ur right memeloo..

My Project A is a console application.
Project B is a class library.
Project C is also a class library.

[memeloo]

I'm not sure becasue I cannot prove it but I think there are two "static instances" of C, one in the scope of A and one in the scope of B so it won't work... we need someone with greater knowledge ; ]

[MNovy]

yes ur right memeloo..

My Project A is a console application.
Project B is a class library.
Project C is also a class library.

It does not matter, where the classes are stored. If in the same file or in an extra .cs
The method is always the same!