How to update values from a field?

[lucasalf11]

Hey guys, I'm new programming in C#, and I need to update a value from a textbox... This happens after an if statement, if it occurs the value of the textbox is changed, I know that the value is changed, but in the Form it isn't displayed, this is what I have so far

if (valoresUni.respuesta == 0)
                {


                    txtp.Text = ParametrosG.P.ToString();
                    txtm.Text = ParametrosG.M.ToString();
                    txtps.Text = ParametrosG.PS.ToString();
                    txtpm.Text = ParametrosG.PM.ToString();
                    txtnumero.Text = valorPlantilla.valor;

                    txtp.Update();
                    txtps.Update();
                    txtpm.Update();
                    txtm.Update();
                }