Question

I have created a dictionary in Class A and would like to return the entire list (Key, Value) in class B. Are there any suggestions on how can I do this? I have tried a number of things from the internet but nothing seems to be working. I am trying to write a method in class A to retrieve the entire dictionary.

public class_A
{
  public static Dictionary<string, string> Dict_1 = new Dictionary();
  public add_dict(string name, string add)
  {
     Dict_1.Add(name, add);
  }

  public dict return_dictionary()
  {
    return (Dict_1); // I want to have a proper code to return this dictionary.
  }
}

Answer 1

If this dictionary is a private member in your class. You can access this Dictionary by an encapuslated method.

public class A
{
    private Dictionary<string, int> _items { set;get;}
    public Dictionary<string, int> GetItems()
    {
        return _items 
    }
}

and in class B, Create an object and access it

A objA = new A();
Dictionary<string, int> thatItems=objA.GetItems();

EDIT : As per the edit in the question
You have some propblems in your code.

You can not write a class like this public class_A. It should be public class A

Your Dictionary declaration should be like this

public static Dictionary<string, string> Dict_1 = new Dictionary<string, string>();

Your add_dict method needs a return type. ( I am just adding void, you can have a bool or whatever you wish)

public void add_dict(string name, string add)
{
    Dict_1.Add(name, add);
}

Your method return type should be Dictionary<string, string>. They you are good.

public Dictionary<string, string> return_dictionary()
{
    return Dict_1;
}

But look into your code, Your Dict_1 property is a public property. So you another class dont even need your return_dictionary method to get the data. It can simply access the data like

A objA = new A();
Dictionary<string, string> stolenData = objA.Dict_1;

So Encapsulation concept is broken !

Better you should keep your member as private like this. I just changed your method names and variable names to follow some coding/naming conventions for better readability.

public class A
{
    private Dictionary<string, string> _dict = new Dictionary<string, string>();
    public void Add_dict(string name, string add)
    {
        _dict.Add(name, add);
    }
    public Dictionary<string, string> Return_dictionary()
    {
        return _dict; 
    }
}

This is a good reading to understand Encapsulation http://www.csharp-station.com/Tutorials/lesson19.aspx