網站開發，善用 Cached DataTable 可以使網站效能倍增，不必一直去資料庫抓資料。
但是使用 Cached DataTable 有一個地方要注意
就是他是 Shared 物件，表示同時有好幾個頁面都可以存取他
例如A網頁將資料抓出，然後變更裡面的DataRow資料，
另一個B網頁也會跟著變更
由於 Cached DataTable 在 Set DataRow Value 時
可能 Critical Section 沒有處理好，若真的同時多個thread 操作
會出現 Exception
(System.ArgumentOutOfRangeException: 索引超出範圍。必須為非負數且小於集合的大小。)
建議:
'這是 UNT FixPage 物件抓取單一資料的範例
Shared Function GetSpecialPage2FromCachedDT(ByVal Key As Int32) As DB.SpecialPage2
Dim DT As DataTable = GetAllDataFromBaseTableWithCache()
Dim Row As DataRow = DT.Rows.Find(Key)
If Row IsNot Nothing Then
'避免每個thread都共用table 寫入資料會出現問題
Dim newDT As DataTable = DT.Clone()
newDT.ImportRow(Row)
Return New SpecialPage2(newDT.Rows(0))
Else
Return Nothing
End If
End Function
<body> <!--BodyTop--> {DebugMessage} <a id="anchorGoTop" href="#gotop" class="gotop" style="display: none;"><span><em></em></span></a>
'購物button區塊置於 <body> 正下方 Me.strBodyTop = Me.otContent.SubTemplate("BuyButtonArea").Result就可以了
Imports System.Runtime.CompilerServices Imports Microsoft.VisualBasic Public Module DateTimeExtension ''' <summary> ''' 將系統時間轉為當地的時間並轉為字串 ''' </summary> ''' <param name="dtSystem"></param> ''' <returns></returns> ''' <remarks></remarks> <Extension()> _ Public Function ToCountryDateTimeString(ByVal dtSystem As DateTime) As String If dtSystem = DateTime.MinValue Then Return "n/a" End If Dim cstTime As DateTime = dtSystem.ToCountryDateTime() ' tr-TR -> dd.MM.yyyy HH:mm:ss Dim langCode As String = SHOPUNT.DB.SysConfig.GetSysConfig("DefaultLangCode") Dim culture As New System.Globalization.CultureInfo(langCode) If cstTime.AddMonths(6) < Now Then Return cstTime.ToString("dd.MM.yyyy HH:mm", culture) Else Return cstTime.ToString("dd.MMM HH:mm", culture) End If End Function ''' <summary> ''' 將系統時間轉為當地的時間 ''' </summary> ''' <param name="dtSystem"></param> ''' <returns></returns> ''' <remarks></remarks> <Extension()> _ Public Function ToCountryDateTime(ByVal dtSystem As DateTime) As DateTime Dim cstZone As TimeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById(SHOPUNT.DB.SysConfig.GetSysConfig("DefaultTimeZone")) Dim localZone As TimeZoneInfo = TimeZoneInfo.Local Dim cstTime As DateTime = TimeZoneInfo.ConvertTime(dtSystem, localZone, cstZone) Return cstTime End Function ''' <summary> ''' 將使用者輸入的時間轉為系統時間 ''' </summary> ''' <param name="dtCountry"></param> ''' <returns></returns> ''' <remarks></remarks> <Extension()> _ Public Function ToSystemDateTime(ByVal dtCountry As DateTime) As DateTime Dim cstZone As TimeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById(SHOPUNT.DB.SysConfig.GetSysConfig("DefaultTimeZone")) Dim localZone As TimeZoneInfo = TimeZoneInfo.Local Dim sysTime As DateTime = TimeZoneInfo.ConvertTime(dtCountry, cstZone, localZone) Return sysTime End Function End Module使用上 只要
Sub SendMail_godaddy(ByVal Subject As String, ByVal Body As String, ByVal FromMail As String, ByVal ToMail As String)
Dim objMail As New System.Web.Mail.MailMessage()
objMail.From = FromMail
objMail.To = ToMail
objMail.Subject = Subject
objMail.BodyFormat = Mail.MailFormat.Html
objMail.Priority = Mail.MailPriority.High
objMail.Body = Body
System.Web.Mail.SmtpMail.SmtpServer = UW.Mail.SMTP_SERVER_NAME
System.Web.Mail.SmtpMail.Send(objMail)
End Sub
Sub SendMail_gmail(ByVal Subject As String, ByVal Body As String, ByVal FromMail As String, ByVal ToMail As String)
Dim msg As New System.Net.Mail.MailMessage
Dim client As New System.Net.Mail.SmtpClient
Try
msg.Subject = Subject
msg.Body = Body
msg.From = New System.Net.Mail.MailAddress(FromMail)
msg.To.Add(ToMail)
msg.IsBodyHtml = True
client.Host = "smtp.gmail.com"
Dim basicauthenticationinfo As System.Net.NetworkCredential = New System.Net.NetworkCredential("username@gmail.com", "password")
client.Port = Int32.Parse("587")
client.EnableSsl = True
client.UseDefaultCredentials = False
client.Credentials = basicauthenticationinfo
client.DeliveryMethod = Net.Mail.SmtpDeliveryMethod.Network
client.Send(msg)
Catch ex As Exception
UW.WU.DebugWriteLine(ex.ToString, True, True)
End Try
End Sub