private void buttonLogin_Click_1(object sender, EventArgs e)
        {
            button2.Visible              = false;
            buttonLogin.Visible          = false;
            pictureBox1.Visible          = false;
            pictureBox2.Visible          = false;
            pictureBox3.Visible          = false;
            pictureBox4.Visible          = false;
            txtBoxPassword.Visible       = false;
            txtBoxUser.Visible           = false;
            pictureBox5.Visible          = true;
            circularProgressBar1.Visible = true;
            circularProgressBar1.Value   = 0;
            circularProgressBar1.Controls.Add(pictureBox5);
            pictureBox5.Location  = new Point(-6, -7);
            pictureBox5.BackColor = Color.Transparent;
            circularProgressBar1.Update();
            pictureBox5.BringToFront();
            for (int i = 0; i < 101; i++)
            {
                Thread.Sleep(5);
                circularProgressBar1.Value = i;
                circularProgressBar1.Update();
            }
            if (circularProgressBar1.Value == 100)
            {
                switch (validateUser())
                {
                case 1:
                    formMdiAdmin formMdiAdmin = new formMdiAdmin();
                    formMain     form1        = new formMain();
                    {
                        this.Hide();
                        formMdiAdmin.ShowDialog();
                        this.Show();
                    }

                    break;

                case 2:
                    formLoginEstudiante formLoginEstudiante = new formLoginEstudiante();
                    formLoginEstudiante.userID = txtBoxUser.Text;
                    formMain form2 = new formMain();
                    {
                        this.Hide();
                        formLoginEstudiante.ShowDialog();
                        this.Show();
                    }


                    break;

                case 3:
                    MessageBox.Show("El nombre de usuario o la contraseña ingresada son incorrectos. Por favor, intentelo nuevamente.", "Error",
                                    MessageBoxButtons.OK, MessageBoxIcon.Warning);
                    break;
                }
            }

            button2.Visible              = true;
            buttonLogin.Visible          = true;
            pictureBox1.Visible          = true;
            pictureBox2.Visible          = true;
            pictureBox3.Visible          = true;
            pictureBox4.Visible          = true;
            txtBoxPassword.Visible       = true;
            txtBoxUser.Visible           = true;
            circularProgressBar1.Visible = false;
            circularProgressBar1.Update();
            circularProgressBar1.Value = 0;
            circularProgressBar1.Update();
            txtBoxUser.Text     = "";
            txtBoxPassword.Text = "";
            txtBoxUser.Focus();
        }