C# 在类库中访问会话。
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Access session in class library.
提问by Bikash Shrestha
I am developing an application architecture that uses 2 sub projects: a) asp.net web application (it covers user interface and business logic) and b) class library. (it covers data access layer)
我正在开发一个使用 2 个子项目的应用程序架构：a) asp.net web 应用程序（它涵盖用户界面和业务逻辑）和 b) 类库。（它涵盖了数据访问层）
After system user successfully logs in , the user information is stored in a session object.
系统用户登录成功后，用户信息保存在一个会话对象中。
The problem I am facing is when I try to access that session object in class library project(data access layer), it always returns null.
我面临的问题是当我尝试访问类库项目（数据访问层）中的会话对象时，它总是返回 null。
I need to access the session object in class library project because, in my case each user has their own username and password for database access(for security reasons);
我需要访问类库项目中的会话对象，因为在我的情况下，每个用户都有自己的数据库访问用户名和密码（出于安全原因）；
So, How how do i read and write from/to session object in class library project
那么，我如何在类库项目中读写会话对象
回答by geekchic
Use the System.Web.HttpContext.Current.Sessionobject.
使用System.Web.HttpContext.Current.Session对象。
回答by Giedrius
First of all, as Peri correctly noticed - you need to think again if having separate database logins for each user is a good idea - because you loose connection pooling (different users won't be able to reuse existing connections - and creating a new sql connection is quite expensive).
首先，正如 Peri 正确注意到的那样-您需要重新考虑是否为每个用户使用单独的数据库登录是个好主意-因为您失去了连接池（不同的用户将无法重用现有连接-并创建一个新的 sql连接相当昂贵）。
If you really wish to keep separate database users, I would create interface to abstract session from data access:
如果您真的希望保留单独的数据库用户，我将创建接口以从数据访问中抽象会话：
public interface ILoginDataService
{
LoginData Current { get; }
}
And implementation would pass login data from session. In such way you won't have session dependency to session in your data access logic - so it will be more testable, also you'll separate concerns.
并且实现将从会话传递登录数据。通过这种方式，您的数据访问逻辑中不会有会话依赖于会话 - 因此它将更易于测试，您也将分离关注点。
回答by user1496412
Here is the code I used within a library to get session information.
这是我在库中用于获取会话信息的代码。
public static string Entity()
{
string entity = "";
HttpContext httpContext = HttpContext.Current;
if (httpContext.ApplicationInstance.Session.Count > 0)
entity = httpContext.ApplicationInstance.Session["EntityCode"].ToString();
return entity;
}
回答by FaheemMCFC
I am having an ASP.Net application which uses session. I am able to access it in my app_code files using [WebMethod(EnableSession = true)] for the function. I am not sure whether this is your problem. I also faced session value as null when I removed (EnableSession = true) on the method.
我有一个使用会话的 ASP.Net 应用程序。我可以在我的 app_code 文件中使用 [WebMethod(EnableSession = true)] 来访问它。我不确定这是否是您的问题。当我在方法上删除 (EnableSession = true) 时，我还面临会话值为 null。
回答by Ahmed Mohammed Fahmy
using System.Web;
namespace ClassNameSpace
{
public class Class1 : IRequiresSessionState
{
private string sessionValue => HttpContext.Current.Session["sessionKey"].ToString();
}
}