溢出异常C＃对于Int32来说，值太大或太小

Question

我收到此错误，如果我尝试将Int32转换为Int64，因为我尝试在数据库中添加一个电话号码，电话号码为10位，异常以9位数字引发。谁能告诉我更好的方法吗？

 private void textBox_Click(object sender, EventArgs e)
    {
        using (PhoneAppDBEntities dbcontext = new PhoneAppDBEntities())
        {

            PhoneBookTable aMessage = new PhoneBookTable();

            int counter = 0;
            long number = Convert.ToInt64(phoneNumberBox.Text);
            string last = lastNameBox.Text;
            string first = firstNameBox.Text;
            int[] phoneList = new int[10];
            string[] firstName = new string[10];
            string[] lastName = new string[10];
            phoneList[counter] = Convert.ToInt32(number);
            firstName[counter] = first;
            lastName[counter] = last;
            aMessage.phoneNumber = number;
            aMessage.lastName = last;
            aMessage.firstName = first;

            if (string.Equals(phoneList[counter], ""))
            {

                dbcontext.PhoneBookTables.Add(aMessage);


            }

            dbcontext.SaveChanges();
            output.Text = "First Name: " + aMessage.firstName + "\r\nLast Name: " + aMessage.lastName + "\r\nPhone Number: " + aMessage.phoneNumber;

            counter++;



        }
    }