private void button1_Click(object sender, EventArgs e) { if (SQLFunctions.checkExistsClassroom(textBox_ClassName.Text) == false) { SQLFunctions.addClassroom(textBox_ClassName.Text, Convert.ToInt32(textBox_Capacity.Text)); MessageBox.Show("class " + textBox_ClassName.Text + " was added with " + textBox_Capacity.Text + " seats."); this.Hide(); FormMenuAdmin adminForm = new FormMenuAdmin(); adminForm.Show(); } else { MessageBox.Show("class " + textBox_ClassName.Text + " is already exists."); } }