Unity的注册表校验（C#）

using UnityEngine;
using System.Collections;

public class UserRegister : MonoBehaviour {

    void Start () {
       
    }
    public string username = "";
    public string password = "";
    public string rePassword = "";
    public string age = "";
    public string email = "";
    public string gender = "";

    public string showmessage = "";
    public void OnGUI() {

        GUILayout.Label(showmessage);
        GUILayout.Label("用户名：");//用户名（5-10位，只能有字幕，数字，_组成，姓名里只能带有sb两个字）
        username= GUILayout.TextField(username);
        GUILayout.Label("密码：");//（长度为6—10位）
        password = GUILayout.TextField(password);
        GUILayout.Label("重复密码：");
        rePassword = GUILayout.TextField(rePassword);
        GUILayout.Label("年龄：");//1-100
        age = GUILayout.TextField(age);
        GUILayout.Label("Email：");//有一个@，以.com .net  .cn 结尾
        email = GUILayout.TextField(email);
        GUILayout.Label("性别：");//男  或女
        gender = GUILayout.TextField(gender);
        checkInput();
    }
    private string[] domainArray = new string[] { ".com", ".net", ".cn" };
    private void checkInput()
    {
        showmessage = "";
        if (username == "")
        {
            showmessage += "用户名不能为空\n";
        }
        else if (username.Length < 5 || username.Length > 10)
        {
            showmessage += "用户名是5-10位\n";
        }
        else {
            for (int i = 0; i < username.Length; i++)
            {
                char c = username[i];
                if ((c >= ‘a‘ && c < ‘z‘) || (c > ‘A‘ && c <= ‘Z‘) || (c >= ‘0‘ && c < ‘9‘) || (c == ‘_‘))
                { }
                else
                {
                    showmessage += "用户名只能有字幕，数字，_组成\n";
                }
            }
            if (username.IndexOf("sb") != -1)
            {
                showmessage += "用户名里面不能有敏感字样\n";
            }
        }
        if (password.Length < 6 || password.Length > 10) {
            showmessage += "密码长度为6-10位\n";
        }
        if (rePassword != password) {
            showmessage += "两次输入的密码不一致\n";
        }
        int ageTemp=0;
        if (!int.TryParse(age, out ageTemp))
        {
            showmessage += "年龄必须输入数字\n";
        }else {
            if (ageTemp <= 0 || ageTemp > 100) {
                showmessage += "年龄的范围必须为1-100\n";
            }
        }
        if (email.IndexOf("@") == -1)
        {
            showmessage += "邮箱输入的格式不合法\n";
        }else {
            bool isRight=false;
            for (int i = 0; i < domainArray.Length; i++) {
                if (email.EndsWith(domainArray[i])) {
                    isRight = true; break;
                }
            }
            if (!isRight) {
                showmessage += "邮箱输入的格式不合法\n";
            }
        }
        if (gender == "男" || gender == "女")
        {
        }
        else {
            showmessage += "性别必须填写男或者女";
        }
    }
}