private void TbCedula_TextChanged(object sender, EventArgs e)
        {
            if (tbCedula.Text.Trim() == "")
            {
                errorProvider1.SetError(tbCedula, null);
                flagCedula = false;
            }

            else
            {
                flagCedula = true;
                if (Validaciones.VerificaCedula(tbCedula.Text))
                {
                    int r = Validaciones.verificarCedulaRepetida(tbCedula, conexion);
                    if (r != 0)
                    {
                        tbCedula.ForeColor = Color.Red;
                        errorProvider1.SetError(tbCedula, "Cédula de ciudadanía ya registrada");
                        errorCedula = 1;
                    }
                    else
                    {
                        errorProvider1.SetError(tbCedula, null);
                        tbCedula.ForeColor = Color.Green;
                        errorCedula        = 0;
                    }
                }
                else
                {
                    errorProvider1.SetError(tbCedula, "Cédula de ciudadanía incorrecta");
                    tbCedula.ForeColor = Color.Red;
                    errorCedula        = 2;
                }
            }
        }