Testing

private void btnAddProperty_Click(object sender, EventArgs e)
        {
            DataManager dataManager = new DataManager();
            dataManager.addItemsToListBox(listBx1, textBox3.Text);
        }

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        private void btnSave_Click(object sender, EventArgs e)
        {
         
            student1.form_id = textBox1.Text;
            student1.form_name = textBox2.Text;

         
            DataManager dataManager = new DataManager();

            foreach (string item in listBx1.Items)
            {
                StudentFormProperties properties = new StudentFormProperties();
                properties.element_id = dataManager.generateGuid();
                properties.element_name = item;

                student1.element_propeties.Add(properties);
            }

            dataManager.SerializeObject(student1, "serializedFile2");
        }

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private void btnLoad_Click(object sender, EventArgs e)
        {
            DataManager dataManager = new DataManager();
            StudentForm DeSerializedStudent1 = dataManager.DeSerializeObject("serializedFile2");

            textBox1.Text = DeSerializedStudent1.form_id;
            textBox2.Text = DeSerializedStudent1.form_name;

            for (int i = 0; i < DeSerializedStudent1.element_propeties.ToArray().Length; i++)
            {
                listBx1.Items.Add(DeSerializedStudent1.element_propeties.ToArray()[i].element_name);
            }
        }