会话意外消失

Question

该网站是买/卖网站，代码来自的页面是“添加产品”页面。

问题是，会话（“更改”）由于某种原因而变为无效，我找不到任何错误。 payment.aspx有一个按钮，通过会话（“更改”）将我发回页面。 我看到问题的原因是，当我尝试编辑某个类别时，该类别被重新调整为列表中的第一个。当我调试我看到，本次会议是什么，但它应该是

继承人的代码：

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles BtnSubmit.Click 
     If Not stats > 0 Then 
      If Session("change") IsNot Nothing Then 
       Dim dc As New DataClassesDataContext 
       Dim getP = From prod In dc.Products _ 
          Where prod.ProductID = CInt(Session("change")) _ 
          Select prod 

       If getP.Any Then 
        If rdbSell.Checked = True Then 
         getP.FirstOrDefault.BuySell = True 
        Else 
         getP.FirstOrDefault.BuySell = False 
        End If 
        If ddlSubSubcat.SelectedValue IsNot String.Empty Then 
         getP.FirstOrDefault.CategoryID = CInt(ddlSubSubcat.SelectedValue) 
        Else 
         getP.FirstOrDefault.CategoryID = CInt(ddlSubCat.SelectedValue) 
        End If 

        getP.FirstOrDefault.Content = txtContent.Text.Replace(Environment.NewLine, "<br />") 
        getP.FirstOrDefault.CountyID = CInt(ddlCounty.SelectedValue) 
        getP.FirstOrDefault.E_mail = txtEmail.Text 
        getP.FirstOrDefault.Date = DateTime.Now 
        getP.FirstOrDefault.Active = 0 
        getP.FirstOrDefault.Alias = txtAlias.Text.Replace("'", "''") 
        getP.FirstOrDefault.ShowEmail = 0 
        Dim PreID As Integer = getP.FirstOrDefault.ProductID 
        If chkShowEmail.Checked = True Then 
         getP.FirstOrDefault.ShowEmail = 1 
        Else 
         getP.FirstOrDefault.ShowEmail = 0 
        End If 
        If chkShowPhone.Checked = True Then 
         getP.FirstOrDefault.ShowPhone = 1 
        Else 
         getP.FirstOrDefault.ShowPhone = 0 
        End If 
        getP.FirstOrDefault.Headline = txtHeadline.Text 
        getP.FirstOrDefault.Password = txtPassword.Text 
        getP.FirstOrDefault.Phone = txtPhone.Text 
        getP.FirstOrDefault.Price = txtPrice.Text 

        If chkUnknown.Checked = True Then 
         getP.FirstOrDefault.YearModel = String.Empty 
        Else 
         getP.FirstOrDefault.YearModel = ddlYear.SelectedValue 
        End If 

        For Each item In libPictures.Items 
         Dim i As String = item.ToString 
         Dim imagecheck = From img In dc.Pictures _ 
             Where img.Name = i And img.ProductID = CInt(Session("change")) _ 
             Select img 

         If imagecheck.Any Then 
         Else 
          Dim img As New Picture 
          img.Name = item.ToString 

          img.ProductID = CInt(Session("change")) 
          dc.Pictures.InsertOnSubmit(img) 
          dc.SubmitChanges() 
         End If 
        Next 

        dc.SubmitChanges() 

        Session.Remove("change") 
        Response.Redirect("~/precheck.aspx?id=" + PreID.ToString) 
       End If 
      Else 
       Dim dc As New DataClassesDataContext 
       Dim prod As New Product 
       If rdbSell.Checked = True Then 
        prod.BuySell = True 
       Else 
        prod.BuySell = False 
       End If 
       If ddlSubSubcat.DataValueField IsNot String.Empty Then 
        prod.CategoryID = CInt(ddlSubSubcat.SelectedValue) 
       Else 
        prod.CategoryID = CInt(ddlSubCat.SelectedValue) 
       End If 

       prod.Content = txtContent.Text.Replace(Environment.NewLine, "<br />") 
       prod.CountyID = CInt(ddlCounty.SelectedValue) 
       prod.E_mail = txtEmail.Text 
       prod.Date = DateTime.Now 
       prod.Active = 0 
       prod.Alias = txtAlias.Text.Replace("'", "''") 
       prod.ShowEmail = 0 
       If chkShowEmail.Checked = True Then 
        prod.ShowEmail = 1 
       Else 
        prod.ShowEmail = 0 
       End If 
       If chkShowPhone.Checked = True Then 
        prod.ShowPhone = 1 
       Else 
        prod.ShowPhone = 0 
       End If 
       prod.Headline = txtHeadline.Text 
       prod.Password = txtPassword.Text 
       prod.Phone = txtPhone.Text 
       prod.Price = txtPrice.Text 

       If chkUnknown.Checked = True Then 
        prod.YearModel = String.Empty 
       Else 
        prod.YearModel = ddlYear.SelectedValue 
       End If 

       dc.Products.InsertOnSubmit(prod) 
       dc.SubmitChanges() 
       Dim PreID As Integer = prod.ProductID 

       For Each item In libPictures.Items 
        Dim img As New Picture 
        img.Name = item.ToString 

        img.ProductID = prod.ProductID 
        dc.Pictures.InsertOnSubmit(img) 
        dc.SubmitChanges() 
       Next 
       Session.Remove("change") 
       Response.Redirect("./precheck.aspx?id=" + PreID.ToString, False) 
      End If 
     End If 
     stats = 0 
     'Catch ex As Exception 
     'End Try 

    End Sub 

Answer 1

这取决于应用程序是如何管理会话状态。如果您的会话状态被管理InProc，那么如果应用程序池被回收，那么您的所有会话信息都将丢失。如果发生这种情况，那么在SQL Server中存储会话状态可能是一个不错的选择，它将在应用程序池回收之间持续存在。

更多信息：

ASP.NET Session State Overview

ASP.NET State Management Recommendations