How to show one form text box data in another form

I wonder where you got your idea from...

i got the answer:
public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Form2 frm = new Form2(this);
            frm.Show();
        }
    }

public partial class Form2 : Form
    {
        Form _frm;
        public Form2(Form frm)
        {
            _frm=frm;
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
           Form1 objMain = (Form1)_frm ;
            objMain.textBox1.Text = "Hello";
        }
    }
In this technique, i pass the form1 to Form2 in constructor, then create an object of existing  Form1 and change there value

Thanks to Bangarubabu pureti. But, your answer not helpful for me.
Please see my requirement:
I have 2 forms form1 and form2. First when you run the application form1 will open. In form1 there is one text box and one button. Do not enter any text in that textbox. Please just click on the button. After clicking the button form2 should be displayed. But, do not close form1. In  form2 also there is one text box and one button. Now enter some text in the form2 textbox and click the button. The text should be displayed in the form1 textbox.

Let Us Consider three child forms for One MDI Form say frmChild1,frmchild2, frmchild3 Now we need to send the data from frmchild1 to frmchild2 and frmchild3



Step1: Declare Variables in frmChild1
======================================
Public static String fc1var1="February Fever";

Public static String fc1var2="Only at www.hyderabadtechies.info";


step2:Declare Variables in frmChild2
====================================
public static string getval1fromf1="";

public static string getval2from1="";



step3:Declare Variables in frmChild3
====================================

public static string getval1fromf1="";

public static string getval2from1="";


step4:Place two Buttons on frmChild1 --one with id(Go2F1) and two with id(Go2F2)
==========================================

UnderGo2F1_Click
----------------
this.Hide();

//Creating Instance for second child form

frmchild2 f2 = new frmchild2();

//Assigning firstChilvariable values to secondchild form values

f2.getval1fromf1=fc1var1;
f2.getval2fromf1=fc1var2;
f2.Show();

UnderGo2F2_Click
----------------
this.Hide();

//Creating Instance for second child form

frmChild3 f3= new frmChild3();

f3.getval1fromf1=fc1var1;
f3.getval2fromf1=fc1var2;
f3.Show();

step5:Know in frmchild2 place two textboxes(say txtname,txtmicusergroup)
==========================================

Under frmchild2_Load (Same as for frmchild3_Load)
--------------------
textname.text=getval1fromf1.ToString();

txtmicusergroup=getval2fromf1.ToString();

Then frmchild2 textbox controls Displays February Fever/Only at www.hyderabadtechies.info

I hope this will help You

Happy Programming

   public partial class f2 : Form
    {
        public TextBox t = null;                  //declare a surrogate text box, make it form global
        public f2()
        {
            InitializeComponent();
            t = te;                                        //this is the text box on the form
        }


    public partial class Form1 : Form
    {
        f2 f = new f2();
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            f.Show();
        }

        private void te_KeyUp(object sender, KeyEventArgs e)
        {
            f.t.Text = te.Text;            //te is the text box on form, what ever you enter in this text box will show in the for 2 text box as you enter it,
        }
    }
}


please don't say it does not work, I know it does...

Thanks for your answer. But, this is not helpful for me. Already 2 forms are running form1 and form2. If we enter some text in form2 textbox. It should be displayed in the fom1 textbox. Please see the above code..
 

in form1, try using :
private void button1_Click(object sender, EventArgs e)

        {

            Form2 f2 = new Form2();

            f2.ShowDialog();           

        }

 

the functions Show() and ShowDialog() seems same; but the effect of both are different.