緩存共享類中的數據

有人可以告訴我爲什麼這不會工作嗎？如果我把測試函數放到後面的代碼中，它可以正常工作。如果我把它放到測試類中，數據總是一無所獲。緩存共享類中的數據

Partial Class _Default 
Inherits System.Web.UI.Page 

Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load 
    ASPxGridView1.DataSource = TestClass.Test() 
    ASPxGridView1.DataBind() 
    ASPxLabel1.Text = Now 
End Sub 
End Class 

Public Class TestClass 
Public Shared Function Test() As DataTable 
    Test = DirectCast(HttpContext.Current.Cache("Test"), DataTable) 
    If Test Is Nothing Then 
     Dim sql As String = "SELECT field1,field2,field3 FROM test " 
     Using conn As New SqlConnection(Materials.Conn) 
      Using cmd As New SqlCommand(sql, conn) 
       Dim dep As New SqlCacheDependency(cmd) 
       Test = New DataTable 
       conn.Open() 
       Test.Load(cmd.ExecuteReader(CommandBehavior.CloseConnection)) 
       HttpContext.Current.Cache.Insert("Test", Test, dep, Cache.NoAbsoluteExpiration, TimeSpan.FromHours(24)) 
      End Using 
     End Using 
    End If 
End Function 
End Class

來源

2012-01-30 jocoder

你嘗試過傳遞null而不是那個「dep」嗎？ – 2012-01-30 16:54:28

HttpContext對象是否存在於測試類中的任何有意義的意義上，即那些存在於非常難以測試的ASP.NET WebForms中的醜陋框架對象之一。 – 2012-01-30 16:57:27

這工作，但我想有依賴。我想那麼我的問題是爲什麼不會在共享函數緩存依賴工作。 – jocoder 2012-01-30 16:59:40

您必須返回一些DataTable值！

更新：我加了SqlDependency.Start(connstring)在沒有這條線的情況下你應該看到錯誤。這表明測試是沒有什麼

Public Class TestClass 
Public Shared Function Test() As DataTable 
    Test = DirectCast(HttpContext.Current.Cache("Test"), DataTable) 
    If Test Is Nothing Then 
     Dim sql As String = "SELECT * from categories" 
     Dim constring As String = ConfigurationManager.ConnectionStrings("HalloweenConnectionString").ConnectionString 
     Using conn As New SqlConnection(constring) 
      Using cmd As New SqlCommand(sql, conn) 
       Dim dep As New SqlCacheDependency(cmd) 
       SqlDependency.Start(constring) 
       Test = New DataTable 
       conn.Open() 
       Test.Load(cmd.ExecuteReader(CommandBehavior.CloseConnection)) 
       HttpContext.Current.Cache.Insert("Test", Test, dep, Cache.NoAbsoluteExpiration, TimeSpan.FromHours(24)) 
      End Using 
     End Using 
    End If 
End Function

末級

來源

2012-01-30 17:06:48 Mubarek

返回數據不是問題。如果將函數本身視爲表格，則不必返回。即Test.Load（cmd.ExecuteReader（CommandBehavior.CloseConnection）） – jocoder 2012-01-30 17:13:26

@ jocoder-你是對的，我認爲這是一個變量！ – Mubarek 2012-01-30 17:28:46

更新，試試吧！ – Mubarek 2012-01-30 17:42:43

這是我怎麼會做這件事。我還不清楚爲什麼我必須通過sqlcachedepency。

Partial Class _Default 
Inherits System.Web.UI.Page 
Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load 
    Dim dep As SqlCacheDependency = Nothing 
    ASPxGridView1.DataSource = TestClass.Test(dep) 
    ASPxGridView1.DataBind() 
    ASPxLabel1.Text = Now 
End Sub 
End Class 

Public Class TestClass 
Public Shared Function Test(ByRef dep As SqlCacheDependency) As DataTable 
    Test = DirectCast(HttpRuntime.Cache("Test"), DataTable) 
    If Test Is Nothing Then 
     Dim sql As String = "SELECT field1,field2,field3 FROM test " 
     Using conn As New SqlConnection(Materials.Conn) 
      Using cmd As New SqlCommand(sql, conn) 
       dep = New SqlCacheDependency(cmd) 
       Test = New DataTable 
       conn.Open() 
       Test.Load(cmd.ExecuteReader(CommandBehavior.CloseConnection)) 
       HttpRuntime.Cache.Insert("Test", Test, dep, Cache.NoAbsoluteExpiration, TimeSpan.FromHours(24)) 
      End Using 
     End Using 
    End If 
End Function 
End Class

來源

2012-01-31 15:08:14 jocoder

緩存共享類中的數據

回答

相關問題