Session problem when accessed through pagemethods_问答_开发者

I have a problem with accessing values in the session through pagemethods.

The example below demonstrates the problem in a simple form. There are three buttons on the page and each of these invokes a different pagemethod, that, in turn accesses what I would expect to be the same variable from the session. In fact the value returned is different for each pagemethod, as demonstrated below.

I only get this problem when I deploy to the webserver; it's not an issue when I test it locally.

Example output:

Method       Session Value
DoMethod1   597cbe1c-5391-4b93-af6b-0da0068b264b
DoMethod2   35df48aa-8a58-4008-b353-be7b9f950395
DoMethod3   35df48aa-8a58-4008-b353-be7b9f950395
DoMethod1   597cbe1c-5391-4b93-af6b-0da0068b264b
DoMethod2   597cbe1c-5391-4b93-af6b-0da0068b264b
DoMethod1   35df48aa-8a58-4008-b353-be7b9f950395
DoMethod3   35df48aa-8a58-4008-b353-be7b9f950395
DoMethod1   597cbe1c-5391-4b93-af6b-0da0068b264b
DoMethod2   597cbe1c-5391-4b93-af6b-0da0068b264b
DoMethod3   35df48aa-8a58-4008-b353-be7b9f950395




Imports System.Web.Services

Public Class MethodResult
    Public MethodName As String
    Public SessionID As String
    Public SessionValue As Object
End Class

Partial Public Class sessiontest
    Inherits System.Web.UI.Page

    <WebMethod()> _
    Public Shared Function DoMethod1() As MethodResult
        If HttpContext.Current.Session("sharedvalue") Is Nothing Then
            HttpContext.Current.Session("sharedvalue") = Guid.NewGuid
        End If
        Dim ret = New MethodResult
        ret.MethodName = "DoMethod1"
        ret.SessionID = HttpContext.Current.Session.SessionID
        ret.SessionValue = HttpContext.Current.Session("sharedvalue")
        Return ret
    End Function


    <WebMethod()> _
    Public Shared Function DoMethod2() As MethodResult
        If HttpContext.Current.Session("sharedvalue") Is Nothing Then
            HttpContext.Current.Session("sharedvalue") = Guid.NewGuid
        End If
        Dim ret = New MethodResult
        ret.MethodName = "DoMethod2"
        ret.SessionID = HttpContext.Current.Session.SessionID
        ret.SessionValue = HttpContext.Current.Session("sharedvalue")
        Return ret

    End Function


    <WebMethod()> _
    Public Shared Function DoMethod3() As MethodResult
        If HttpContext.Current.Session("sharedvalue") Is Nothing Then
            HttpContext.Current.Session("sharedvalue") = Guid.NewGuid
        End If
        Dim ret = New MethodResult
        ret.MethodName = "DoMethod3"
        ret.SessionID = HttpContext.Current.Session.SessionID
        ret.SessionValue = HttpContext.Current.Session("sharedvalue")
        Return ret

    End Function

End Class


<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="sessiontest.aspx.vb"    Inherits="project1.sessiontest" %>
<!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 runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="true" />
    <script type="text/javascript">
        function method1() {
            PageMethods.DoMethod1(methodComplete);
        }
        function method2() {
            PageMethods.DoMethod2(methodComplete);
        }
        function method3() {
            PageMethods.DoMethod3(methodComplete);
        }
        //complete
        function methodComplete(result) {
            document.getElementById('output').innerHTML += "<tr><td>" + result.MethodName + "</td><td>" + result.SessionID + "</td><td>" + result.SessionValue + "</td></tr&开发者_JAVA百科gt;";
        }

    </script>    
    <div>
        <input type="button" value="Method 1" onclick="method1();" id="btn1" />
        <br />
        <input type="button" value="Method 2" onclick="method2();" id="Button1" />
        <br />
        <input type="button" value="Method 3" onclick="method3();" id="Button2" />
        <br />
        <table id="output" style="width:100%;">
            <tr>
                <th>Method Name</th>
                <th>Session ID</th>
                <th>Session Value</th>
            </tr>
        </table>
    </div>
    </form>
</body>
</html>

You need to enable session state for your web methods.

Example:

<WebMethod(EnableSession:=True)> _
Public Shared Function DoMethod1() As MethodResult
    If HttpContext.Current.Session("sharedvalue") Is Nothing Then
        HttpContext.Current.Session("sharedvalue") = Guid.NewGuid
    End If
    Dim ret = New MethodResult
    ret.MethodName = "DoMethod1"
    ret.SessionID = HttpContext.Current.Session.SessionID
    ret.SessionValue = HttpContext.Current.Session("sharedvalue")
    Return ret
End Function

check out this msdn article for more information.