How to get value form one textbox from one form to another?

You first need to get a reference to the form the textbox is on.

Suppose it's on a form called Form2. Then an easy way of getting a reference to Form2 from another form is as follows:

  Form2 f2 = (Form2)Application.OpenForms["Form2"];

Next you need to get a reference to the textbox itself (textBox1 say). Controls are normally private fields of their containing form but (from the Properties Box) you can change their Modifiers property to internal or public.

You can then simply do:

  string text = f2.texBox1.Text;

You can also do it without changing the Modifiers property by going through the form's Controls property:

  TextBox tb = (TextBox)f2.Controls["textBox1"];
  string text = tb.Text;

However, this assumes that the textbox has been placed directly on the form. If it's been placed instead in some container such as panel1 say, then you can still use this approach but the code is more complicated.

  Panel p = (Panel)f2.Controls["panel1"];
  TextBox tb = (TextBox)p.Controls["textBox1"];
  string text = tb.Text;

 Hi santhosh


 Deaclare public variable 
   
 assign the value of textbox


 use that variable in another form


  like
 
   public string txtval ="";

   txtval = TextBox1.Text;

use txtval variable in another form. you can also define this variable in public.

TextBox2.Text=txtval;