课程追踪进度等级 [英] course tracking progress level

问题描述

我正在做学习管理系统(LMS)项目，这里要制作课程跟踪器的课程跟踪器是当一个用户注册此Lms并登录到Lms时，他选择该课程并学习了该课程.当然，如果第二章进行了测试，则用户完成了第二章后会转到测试屏幕，完成测试后，用户要转到跟踪器的第三章.


我正在为userid创建会话.此会话用于使用用户方法获取用户详细信息.所有会话均在onload方法中的跟踪器屏幕中分配给某个变量

总是用户从跟踪器屏幕上开始课程.如果用户开始课程，则正在调用onload方法，这时屏幕上出现以下错误对象引用不是要设置对象的实例"

因为会话值是在测试屏幕中分配的.如果我不转到测试屏幕，则会话值将分配为null.如果会话为null的值，则它想正常工作.

因此，如何为session设置null值.如果我为session设置null值，则不希望给出错误

i am doing learning management System(LMS) project,here want to make course tracker course tracker is when one user register this Lms and login to the Lms ,then he choose the course,and studied the course.when during study the course ,if second chapter have test ,the user finished second chapter it goes to the test screen,after complete the test the user want to go to the third chapter of tracker.


i am create session for userid .this session is used to get user detail using user method .all session are assign to some variable in tracker screen in onload method

always user start a course from tracker screen.if user start a course,the onload method are calling,in this time following error are appear in the screen "object reference are not to set an instance of a object"

because the session value are assign in test screen.if i does not go to the test screen ,session value are assign to null.if session is null value it want to work properly.

so ,how to set null value to session.if i set null value to session ,it do not want to give the error

推荐答案

您可以设置一些检查条件如果该Session变量存在并且具有一定的价值.然后再执行您编写的任何代码.

You can put some conditions for checking if that Session variable exists and has some value. Only then execute whatever code you have written.

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