如何在课堂上获得会话价值？ [英] How to get session value in class anywhere ?

问题描述

大家好。我在ASP.net中有一些会话如下。在文件Test.aspx.cs中有一些会话

 HttpContext.Current.Session [   Id] = obj.USER_MOD_ID; 
 HttpContext.Current.Session [  Group] = obj.GROUP_MOD_ID; 
 HttpContext.Current.Session [  Region] = obj.REGION_ID; 
 

然后我创建了一些课程，我希望得到会话的价值。



首先，我创建一个类MySession.cs

  public   class  MySession 
 {
  //  私有构造函数 
  private  MySession（）
 {
 value_group =   Group; 
  //   value_id =Id;  
  //   value_region =Region;  
} 
  / /  获取当前会话。 
  public  静态 MySession当前
 {
 获取 
 {
 MySession session =（MySession）HttpContext .Current.Session [  Group]; 
  if （session ==  null ）
 {
 session =  new  MySession（）; 
 HttpContext.Current.Session [  Group] = session; 
} 
  return  session; 
} 
} 
  //   ****在此添加会话属性，例如： 
  public   string  value_group {获得;  set ; } 
  //   public string value_id {get;组; }  
  //   public string value_region {get;组; }  
} 
 

其次，我创建了类Test.cs，我希望获得价值会话

  string  value_group = MySession.Current.value_group.ToString （）; 
  //   string value_id = MySession.Current.value_id.ToString（）;  
  //   string value_region = MySession.Current.value_region.ToString（）;  
 

但是它会收到错误

 < span class =code-sdkkeyword> Object 引用 set 为 object  

谢谢大家。

解决方案

 MySession session =（MySession）HttpContext.Current.Session [  Group]; 

这个演员是问题。

请尝试使用它：

 MySession session = HttpContext.Current.Session [ 组]  as  MySession; 

如果当前即时返回会话，更改以下代码

  public   class  MySession 
 {
  //  私有构造函数 
 私有 MySession（）
 {
 Group =  初始组值; 
} 
  //  获取当前会话。 
  public   static  MySession当前
 {
  get  
 {
 MySession session =（MySession）HttpContext.Current.Session [  MySession的]; 
  if （session ==  null ）
 {
 session =  new  MySession（）; 
 HttpContext.Current.Session [  MySession] = session; 
} 
  return  session; 
} 
} 
 
  public   string 组{  get ;  set ; } 
 
} 
 

那么你需要访问会话值为

  string  value_group = MySession.Current.Group; 

Hello guys. I have some sessions in ASP.net as follow . In file Test.aspx.cs have some session

HttpContext.Current.Session["Id"] = obj.USER_MOD_ID;
HttpContext.Current.Session["Group"] = obj.GROUP_MOD_ID;
HttpContext.Current.Session["Region"] = obj.REGION_ID;

And then i create some class , I want to get value of session.

First , i create a class MySession.cs

public class MySession
   {
       // private constructor
       private MySession()
       {
           value_group = "Group";
           //value_id = "Id";
           //value_region = "Region";
       }
       // Gets the current session.
       public static MySession Current
       {
           get
           {
               MySession session =(MySession)HttpContext.Current.Session["Group"];
               if (session == null)
               {
                   session = new MySession();
                   HttpContext.Current.Session["Group"] = session;
               }
               return session;
           }
       }
       // **** add your session properties here, e.g like this:
       public string value_group { get; set; }
       //public string value_id { get; set; }
       //public string value_region { get; set; }
   }

Second, i create class Test.cs and i want get value of session

string value_group = MySession.Current.value_group.ToString();
               //string value_id = MySession.Current.value_id.ToString();
               //string value_region = MySession.Current.value_region.ToString();

But it's get error

Object reference not set to an instance of an object 

Thank guys.

解决方案

MySession session = (MySession)HttpContext.Current.Session["Group"];

This casting is the issue.
Try using this instead:

MySession session = HttpContext.Current.Session["Group"] as MySession;

if the Current is returning session instant, change the code as below

public class MySession
   {
       // private constructor
       private MySession()
       {
           Group= "Initial Group Value";
       }
       // Gets the current session.
       public static MySession Current
       {
           get
           {
               MySession session =(MySession)HttpContext.Current.Session["MySession"];
               if (session == null)
               {
                   session = new MySession();
                   HttpContext.Current.Session["MySession"] = session;
               }
               return session;
           }
       }

       public string Group { get; set; }

   }

then you need to access session value as

string value_group = MySession.Current.Group;

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