c# - 如何在 Threaded .Net Webservice 中启用会话？

Question

我有一个具有以下两种方法的 .Net Webservice：

[WebMethod(EnableSession = true)]
public void A()
{
   HttpSessionState session = Session;

   Thread thread = new Thread(B);
   thread.Start();
}

[WebMethod(EnableSession = true)]
public void B()
{
   HttpSessionState session = Session;
}

场景1）直接调用B方法时，session不为null

场景 2）但是当我调用A时，在B中 session 和 HttpContext.Current 都是空的。

为什么？如何在第二种情况下启用B中的会话？如何访问 A 中的会话？我应该将其会话传递给 B 吗？如果是怎么办？

方法 B 不应将会话作为参数。

谢谢，

Answer 1

这是因为您在新线程中启动 B。

请参阅http://forums.asp.net/t/1276840.aspx 或 http://forums.asp.net/t/1630651.aspx/1

Answer 2

[WebMethod(EnableSession = true)]
public void A()
{
   HttpSessionState session = Session;

   Action action = () => B_Core(session);
   Thread thread = new Thread(action);
   thread.Start();
}

[WebMethod(EnableSession = true)]
public void B()
{
   HttpSessionState session = Session;
   B_Core(session);
}
private void B_Core(HttpSessionState session)
{
    // todo
}

Answer 3

我必须使用一个全局字段：

/// <summary>
/// Holds the current session for using in threads.
/// </summary>
private HttpSessionState CurrentSession;

[WebMethod(EnableSession = true)]
public void A()
{
   CurrentSession = Session;

   Thread thread = new Thread(B);
   thread.Start();
}

[WebMethod(EnableSession = true)]
public void B()
{
  //for times that method is not called as a thread
  CurrentSession = CurrentSession == null ? Session : CurrentSession;

   HttpSessionState session = CurrentSession;
}