求大神给指点下这些代码有什么问题啊，为什么session变量不生效啊-PHP Tutorial-php.cn

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求大神给指点下这些代码有什么问题啊，为什么session变量不生效啊

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Jun 23, 2016 pm 01:59 PM

<?php require_once('Connections/yiwuyiwu.php'); ?><?phpif (!function_exists("GetSQLValueString")) {function GetSQLValueString($theValue, $theType, $theDefinedValue = "", $theNotDefinedValue = "") {  $theValue = get_magic_quotes_gpc() ? stripslashes($theValue) : $theValue;  $theValue = function_exists("mysql_real_escape_string") ? mysql_real_escape_string($theValue) : mysql_escape_string($theValue);  switch ($theType) {    case "text":      $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";      break;        case "long":    case "int":      $theValue = ($theValue != "") ? intval($theValue) : "NULL";      break;    case "double":      $theValue = ($theValue != "") ? "'" . doubleval($theValue) . "'" : "NULL";      break;    case "date":      $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";      break;    case "defined":      $theValue = ($theValue != "") ? $theDefinedValue : $theNotDefinedValue;      break;  }  return $theValue;}}mysql_select_db($database_yiwuyiwu, $yiwuyiwu);$query_Recordset1 = "SELECT * FROM `user`";$Recordset1 = mysql_query($query_Recordset1, $yiwuyiwu) or die(mysql_error());$row_Recordset1 = mysql_fetch_assoc($Recordset1);$totalRows_Recordset1 = mysql_num_rows($Recordset1);?><?php// *** Validate request to login to this site.if (!isset($_SESSION)) {  session_start();}// ***session变量开始了$loginFormAction = $_SERVER['PHP_SELF'];if (isset($_GET['accesscheck'])) {  $_SESSION['PrevUrl'] = $_GET['accesscheck'];}if (isset($_POST['Username'])) {  $loginUsername=$_POST['Username'];  $password=(md5($_POST['Password']));  $MM_fldUserAuthorization = "enable";  $MM_redirectLoginSuccess = "index.php";  $MM_redirectLoginFailed = "zhuce.php";  $MM_redirecttoReferrer = false;  //*** 输入账号和密码，判断转向页面。  mysql_select_db($database_yiwuyiwu, $yiwuyiwu);  	  $LoginRS__query=sprintf("SELECT u_id u_name, pass, enable FROM `user` WHERE u_name=%s AND pass=%s",  //*** 启用符号是这个“&middot;”  GetSQLValueString($loginUsername, "text"), GetSQLValueString($password, "text"));      $LoginRS = mysql_query($LoginRS__query, $yiwuyiwu) or die(mysql_error());  $row_LoginRS = mysql_fetch_assoc($LoginRS);  $loginFoundUser = mysql_num_rows($LoginRS);      if ($loginFoundUser) {        $loginStrGroup  = mysql_result($LoginRS,0,'enable');        //***   声明三个会话变量并分配值    $_SESSION['MM_Username'] = $loginUsername;    $_SESSION['MM_UserGroup'] = $loginStrGroup;		$_SESSION['u_id']= $row_LoginRS('u_id');         if (isset($_SESSION['PrevUrl']) && false) {      $MM_redirectLoginSuccess = $_SESSION['PrevUrl'];	    }    header("Location: " . $MM_redirectLoginSuccess );  }  else {    header("Location: ". $MM_redirectLoginFailed );  }}?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title></title></head><body>  <h3 id="登录系统">登录系统</h3>  <hr /><form ACTION="<?php echo $loginFormAction; ?>" id="form1" name="form1" method="POST">  <table width="250" border="1" align="center" cellpadding="0" cellspacing="0">    <tr>      <td colspan="2" nowrap="nowrap" bgcolor="#3366CC"><div align="center"><font color="#FFFFFF">用户登陆</font></div></td>    </tr>    <tr>      <td width="100" nowrap="nowrap"><div align="right"><font color="#000000">用户名:</font></div></td>      <td width="235">                <div align="left">          <input name="Username" type="text" id="Username" />      </div></td>    </tr>    <tr>      <td width="100" nowrap="nowrap"><div align="right"><font color="#000000">密码:</font></div></td>      <td width="235">                <div align="left">          <input name="Password" type="password" id="Password" value="" />      </div></td>    </tr>    <tr>      <td colspan="2"><div align="right">        <a href="/test/zhuce.php">注册</a>        <input type="submit" name="Submit" value="登陆" />      </div></td>    </tr>  </table></form></body></html><?phpmysql_free_result($Recordset1);?>

回复讨论(解决方案)

你怎么知道没有生效的？

你怎么知道没有生效的？
因为登录以后我计划用session变量做了if语句，结果if语句没生效

你用了哪个session，你可以echo一下看是否有值。

你把相关代码贴出来

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