How to use a class from one C# project with another C# project

1. In the 'Solution Explorer' tree, expand the P2 project and then right-click the project and select 'Add Reference' from the menu.
2. On the 'Add Reference' dialog, select the 'Projects' tab and select your P1 project.
3. If you are using namespaces then you will need to import the namespaces for your P1 types by adding 'using' statements to your files in P2.

Note that the types in P1 that you wish to access directly must have a sufficient access level: typically this means they must be made public.

Simply add reference to P1 from P2

Paul Ruane is correct, I have just tried myself building the project. I just made a whole SLN to test if it worked.

I made this in VC# VS2008

<< ( Just helping other people that read this aswell with () comments )

Step1:

Make solution called DoubleProject

Step2:

Make Project in solution named DoubleProjectTwo (to do this select the solution file, right click --> Add --> New Project)

I now have two project in the same solution

Step3:

As Paul Ruane stated. go to references in the solution explorer (if closed it's in the view tab of the compiler). DoubleProjectTwo is the one needing functions/methods of DoubleProject so in DoubleProjectTwo right mouse reference there --> Add --> Projects --> DoubleProject.

Step4:

Include the directive for the namespace:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using DoubleProject; <------------------------------------------

namespace DoubleProjectTwo
{
    class ClassB
    {
        public string textB = "I am in Class B Project Two";
        ClassA classA = new ClassA();


        public void read()
        {
            textB = classA.read();
        }
    }
}

Step5:

Make something show me proof of results:

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

namespace DoubleProject
{
    public class ClassA    //<---------- PUBLIC class
    {
        private const string textA = "I am in Class A Project One";

        public string read()
        {
            return textA;
        }
    }
}

The main

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using DoubleProjectTwo;  //<----- to use ClassB in the main

namespace DoubleProject
{
    class Program
    {
        static void Main(string[] args)
        {
            ClassB foo = new ClassB();

            Console.WriteLine(foo.textB);
            Console.ReadLine();
        }
    }
}

That SHOULD do the trick

Hope this helps

EDIT::: whoops forgot the method call to actually change the string , don't do the same :)