Update textboxes in Form1 on updating the datagridview

Question

Hi all I have coded where my functionality as follows, In my form1 I will have some text boxes and a datagridview where when user click on edit of the datagridview form2 will come as popup and if the user make some changes I will update the changes and rebind the datagridview this is my code

// Form1 Code

public void UpDateData(DataTable dt)

        {

            dataGridView1.Refresh();

            dataGridView1.DataSource = dt;

            updateTextBoxes();

        }

public void updateTextBoxes()

        {

              //  Some caluculation based on the datagridview rows

        }

Form2 Button click code

private void button1_Click(object sender, EventArgs e)

        {

               // Some code to collect the changes made

              Form1 f=new Form1();

              f.UpDateData(lDTGet);

        }

Every thing works fine except the updateTextBoxes method this is not updating the textboxes as per required can some one help me