using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace Test
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            Form2 x = new Form2(this);
            x.Show();
        }

        public void test()
        {
            MessageBox.Show("Working");
        }

    }
}


using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace Test
{
    public partial class Form2 : Form
    {
        public Form2(Form f)
        {
            InitializeComponent();
            f.test();
        }
    }
}