Textbox value cannot get from grid view...

Question

I cannot get textbox values from gridview... 

i am using the following code... I am getting null.... Anyone help me..

            foreach (GridViewRow gridRow in GridView1.Rows)

            {

                Label lbl = (Label)gridRow.FindControl("lblID");

                TextBox serviceFee = (TextBox)gridRow.FindControl("txtServiceFee");

                TextBox typingFee = (TextBox)gridRow.FindControl("txtTypingFee");

                TextBox govermentFee = (TextBox)gridRow.FindControl("txtGovermentFee");

                int customerTypeId = Convert.ToInt32(lbl.Text);

                string sfee = Convert.ToString(serviceFee.Text);
}