و راهی کم هزینه تر با Property:
//In Form1's button handler
using(Form2 form2 = new Form2())
{
if(form2.ShowDialog() == DialogResult.OK)
{
someControlOnForm1.Text = form2.TheValue;
}
}
And...
//In Form2
//Create a public property to serve the value
public string TheValue
{
get { return someTextBoxOnForm2.Text; }
}