插入sql server数据库时,出现问题?帮顶一下,谢谢!!!!

下面的程序是添加注册信息,向数据库插入数据时出现乱码,
请各位帮改一下
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<%@ page Language="C#"%>
<%@ Import Namespace="System.Data" %>
<%@ Import NameSpace="System.Data.SqlClient" %> 
<html>
<body>
<%
   string realname=Request.Form["realname"];
   String certificate=Request.Form["certificate"];
   String username=Request.Form["username"];
   String password=Request.Form["username"];
   string sex=Request.Form["sex"];
   string age=Request.Form["age"];
   string xueli=Request.Form["xueli"];
   string zhichen=Request.Form["zhichen"];
   string position=Request.Form["position"];
   string district=Request.Form["district"];
   string danwei=Request.Form["danwei"];
   string phone=Request.Form["phone"];
   string email=Request.Form["email"];
     SqlConnection mySqlConnection =new SqlConnection(
  "server=localhost;database=SmartExam;uid=sa;pwd=gzedu");
   mySqlConnection.Open();
   
   string check_login="select count(*) from User_Account where Account='"+username+"'";
   SqlCommand MyCommand = new SqlCommand(check_login,mySqlConnection);
   Int32 reg_num=(Int32)MyCommand.ExecuteScalar();
   if(reg_num>=1)
     {
        Response.Write("你已经注册,请不要重复注册!!<br>");
  %>
  <a href="../SmartExam">返回</a><% } 
else{
     string reg_user = "insert into User_Account(Real_Name,Account,Password,User_Sex,Age,Xueli,Zhichen,Zhiwu,Address,Company,Telephone,Email) values('"+realname+"','"+username+"','888888','"+sex+"','"+age+"','"+xueli+"','"+zhichen+"','"+position+"','"+district+"','"+danwei+"','"+phone+"','"+email+"')"; 
    SqlCommand MyComm = new SqlCommand(reg_user,mySqlConnection); 
    int reg_count=MyComm.ExecuteNonQuery();
    if(reg_count>=1)
  {
    Response.Write("注册新用户成功!");
 Response.Write("用户名是:"+username);
         Response.Write("密码是:888888");
%>
<a href="../SmartExam/login.ashx?account=<%=username%>&password=888888">登录</a>
<%
  }
else
    Response.Write("注册用户失败!");
}

    mySqlConnection.Close();
%></body>
</html>