using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace WindowsFormsApplication1

{

    public delegate void ces(string a);

    public partial class Form2 : Form

    {

        ces bbb;

        public Form2(ces aax)

        {

            bbb = aax;

            InitializeComponent();

        }

        private void button1_Click(object sender, EventArgs e)

        {

            bbb(this.textBox1.Text);

        }

    }

}

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace WindowsFormsApplication1

{

    public partial class Form1 : Form

    {

        private string text;

        public Form1()

        {

            InitializeComponent();

        }

        public Form1(string text)

        {

            // TODO: Complete member initialization

            this.text = text;

        }

        private void button1_Click(object sender, EventArgs e)

        {

            Form2 f = new Form2(setmsg);

            f.ShowDialog();

        }

        private void Form1_Load(object sender, EventArgs e)

        {

        }

        public void setmsg(string msg)

        {

            this.label1.Text = msg;

        }

    }

}