How to reference the loaded instance of Class A in Class B

User 7763270

Hi, I have two classes say Class A and Class B. I am trying to find how do I get reference the loaded instance of Class A in Class B. I do not want to get a new instance of Class A. I want to be able to reference to the loaded instance and use the loaded methods and properties. Class A { ... Class A myClass = New Class A(); ... ... Class B clsb = New Class B(); clsb.DoSomething(int a, int b) } Class B { ... public void DoSomething(int a, int b) { .... //I want to be able to reference to the loaded instance which is 'myClass' of the Class A. (not a new instance) } } Can some one please help me with this. Thanks, L .

Dave Kreskowiak

The concept is called the "Singleton[^]" pattern.

A guide to posting questions on CodeProject[^]
Dave Kreskowiak

dan sh

ClassA should provide a static method or a static property which returns the instance created inside it. This method/property will help others access that instance.

"Your code will never work, Luc's always will.", Richard MacCutchan[^]

GlobX

If having a static reference (or the Singleton pattern, basically the same thing) is inappropriate, you could pass it in in the constructor or as a method parameter on class B. I'm surprised this works, though - maybe it's the pseudo-code you've presented, but this:

public class ClassA()
{
private ClassA myClass = new ClassA();
}

is the same as:

public class ClassA()
{
private ClassA myClass = null;

public ClassA()
{
    // infinite loop here ???
    myClass = new ClassA();
}

}

Won't this end up with a stack overflow?

PIEBALDconsult

Pass it to the constructor or a property.

B b = new B() ;

A a = new A ( b ) ;

or

a.B = b ;

dan sh

GlobX wrote:

Won't this end up with a stack overflow?

Why not just run it and see for yourself. I guess it will.

"Your code will never work, Luc's always will.", Richard MacCutchan[^]

GlobX

It was more intended as a rhetorical question, like a "have you thought about this...?" 'sides, too busy hating on BizTalk to play around :(

dan sh

GlobX wrote:

hating on BizTalk

Just work on SharePoint as well and you have witnessed hell. :)

"Your code will never work, Luc's always will.", Richard MacCutchan[^]

Nitheesh George

Hi, You need to use the Singleton pattern to achieve this. Please find the example below public class A { private static A _instance; private A() {} public static A GetInstance() { if(_instance == nulll) _instance = new A(); return _instance; } } public class B { public void Somemethod() { A a = A.GetInstance(); . . . do somethig . . } } Note that we make the constructor of class A private. And class A holds a instance of itself in _instance variable. This is for to make sure that an out side method cannot create an instance of A. Then we will provide a static method in class A like GetInstance where we create a new instance if an instance is already not exist and return the current instance Hope this helps Nitheesh George http://www.simpletools.co.in

PIEBALDconsult

No, never a singleton, especially with .net languages; they're not needed and generally a symptom of poor design. I have never found a situation that wuold benefit from a singleton.

Nitheesh George wrote:

cannot create an instance of A

In .net everyone has access to your privates. And give this[^] a read.