private void btnteacherlogin_Click(object sender, EventArgs e)
{
TeacherLogin tl = new TeacherLogin();
tl.Visible = true;
this.Hide();
}
private void teacherLoginToolStripMenuItem_Click(object sender, EventArgs e)
{
TeacherLogin logout = new TeacherLogin();
logout.Visible = true;
this.Hide();
}
