以下代码用于用户控制（它显示横幅），页面卡在IIS中，状态为Executerequesthandler（当此页面有并发请求时），当我从页面中取出该用户控件时，它运行平稳，请注意，此控件在页面中嵌入了5次。以下是此用户控件的完整代码，有人可以发现问题吗？
Public Class daAds
Private Remote_Host As String
Private Script_Name As String
Private PATH_INFO As String
Private Page_Link As String
Private Country As String
Public Property p_Country() As String
Get
Return Country
End Get
Set(ByVal value As String)
Country = value
End Set
End Property
Public Property p_Page_Link() As String
Get
Return Page_Link
End Get
Set(ByVal value As String)
Page_Link = value
End Set
End Property
Public Property p_Remote_Host() As String
Get
Return Remote_Host
End Get
Set(ByVal value As String)
Remote_Host = value
End Set
End Property
Public Property p_Script_Name() As String
Get
Return Script_Name
End Get
Set(ByVal value As String)
Script_Name = value
End Set
End Property
Private ConnectionToFetch As SqlConnection
Private ReadOnly Property Connection() As SqlConnection
Get
ConnectionToFetch = New SqlConnection(ConnectionString)
ConnectionToFetch.Open()
Return ConnectionToFetch
End Get
End Property
Private ReadOnly Property ConnectionString() As String
Get
Return ConfigurationManager.ConnectionStrings("ConnStr").ConnectionString
End Get
End Property
Public Property p_PATH_INFO() As String
Get
Return PATH_INFO
End Get
Set(ByVal value As String)
PATH_INFO = value
End Set
End Property
Public Function showAd(ByVal Banner_inc As Integer, ByVal banner_layout As String, Optional ByVal ShowAdsInfo As Integer = 0) As String
'Return ""
Try
'Dim connectionString As String = ConfigurationManager.ConnectionStrings("ConnStr").ConnectionString
Dim imp_user_ip As String = Trim(Remote_Host)
Dim imp_country As String = Trim(p_Country)
imp_country = Replace(imp_country, Chr(10), "")
imp_country = Replace(imp_country, Chr(13), "")
Dim imp_page_name As String = Trim(Script_Name)
Dim imp_page_name2 As String = Trim(PATH_INFO)
Dim imp_page_link As String = p_Page_Link
'Response.Write(imp_page_name)
'ParamArrayAttribute()
'Dim m As DataSet
'm = SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, "disp_banner_byPageName_views", parameters)
Dim InsertCommand As New SqlCommand
InsertCommand.Connection = Connection
InsertCommand.CommandText = "disp_banner_byPageName_views"
InsertCommand.CommandType = CommandType.StoredProcedure '
'Dim IdParameter = New SqlParameter("@CategoryID", SqlDbType.Int)
'Dim NameParameter = New SqlParameter("@CategoryName", SqlDbType.NVarChar)
'IdParameter.Direction = ParameterDirection.Output
'NameParameter.Value = txtCategoryName.Text
'InsertCommand.Parameters.Add(IdParameter)
'InsertCommand.Parameters.Add(NameParameter)
Dim Param_Imp_user_ip = New SqlParameter("@imp_user_ip", SqlDbType.VarChar)
Param_Imp_user_ip.Direction = ParameterDirection.Input
Param_Imp_user_ip.Value = imp_user_ip
InsertCommand.Parameters.Add(Param_Imp_user_ip)
Param_Imp_user_ip = Nothing
Dim Param_imp_country = New SqlParameter("@imp_country", SqlDbType.VarChar)
Param_imp_country.Direction = ParameterDirection.Input
Param_imp_country.Value = imp_country '"jo" '
InsertCommand.Parameters.Add(Param_imp_country)
Param_imp_country = Nothing
Dim Param_banner_inc = New SqlParameter("@banner_inc", SqlDbType.Int)
Param_banner_inc.Direction = ParameterDirection.Input
Param_banner_inc.Value = Banner_inc
InsertCommand.Parameters.Add(Param_banner_inc)
Param_banner_inc = Nothing
Dim Param_imp_page_name = New SqlParameter("@imp_page_name", SqlDbType.VarChar)
Param_imp_page_name.Direction = ParameterDirection.Input
Param_imp_page_name.Value = imp_page_name
InsertCommand.Parameters.Add(Param_imp_page_name)
Param_imp_page_name = Nothing
Dim Param_imp_page_link = New SqlParameter("@imp_page_link", SqlDbType.VarChar)
Param_imp_page_link.Direction = ParameterDirection.Input
Param_imp_page_link.Value = imp_page_link
InsertCommand.Parameters.Add(Param_imp_page_link)
Param_imp_page_link = Nothing
Dim Param_banner_layout = New SqlParameter("@banner_layout", SqlDbType.VarChar)
Param_banner_layout.Direction = ParameterDirection.Input
Param_banner_layout.Value = banner_layout
InsertCommand.Parameters.Add(Param_banner_layout)
Param_banner_layout = Nothing
Dim Param_activeBanners = New SqlParameter("@activeBanners", SqlDbType.VarChar)
Param_activeBanners.Direction = ParameterDirection.Input
Param_activeBanners.Value = ""
InsertCommand.Parameters.Add(Param_activeBanners)
Param_activeBanners = Nothing
Dim Param_banner_width = New SqlParameter("@banner_width", SqlDbType.Int)
Param_banner_width.Direction = ParameterDirection.Output
InsertCommand.Parameters.Add(Param_banner_width)
Dim Param_banner_height = New SqlParameter("@banner_height", SqlDbType.Int)
Param_banner_height.Direction = ParameterDirection.Output
InsertCommand.Parameters.Add(Param_banner_height)
Dim Param_campaign_id = New SqlParameter("@campaign_id", SqlDbType.Int)
Param_campaign_id.Direction = ParameterDirection.Output
InsertCommand.Parameters.Add(Param_campaign_id)
Dim Param_imp_id = New SqlParameter("@imp_id", SqlDbType.Int)
Param_imp_id.Direction = ParameterDirection.Output
InsertCommand.Parameters.Add(Param_imp_id)
Dim Param_banner_url = New SqlParameter("@banner_url", SqlDbType.VarChar, 500)
Param_banner_url.Direction = ParameterDirection.Output
InsertCommand.Parameters.Add(Param_banner_url)
Dim Param_banner_img = New SqlParameter("@banner_img", SqlDbType.VarChar, 100)
Param_banner_img.Direction = ParameterDirection.Output
InsertCommand.Parameters.Add(Param_banner_img)
Dim Param_banner_text = New SqlParameter("@banner_text", SqlDbType.VarChar, 1000)
Param_banner_text.Direction = ParameterDirection.Output
InsertCommand.Parameters.Add(Param_banner_text)
Dim Param_banner_script = New SqlParameter("@banner_script", SqlDbType.VarChar, 2000)
Param_banner_script.Direction = ParameterDirection.Output
InsertCommand.Parameters.Add(Param_banner_script)
Dim Param_banner_ID = New SqlParameter("@banner_ID", SqlDbType.Int)
Param_banner_ID.Direction = ParameterDirection.Output
InsertCommand.Parameters.Add(Param_banner_ID)
Dim param_adv_name_script = New SqlParameter("@adv_name", SqlDbType.VarChar, 2000)
param_adv_name_script.Direction = ParameterDirection.Output
InsertCommand.Parameters.Add(param_adv_name_script)
InsertCommand.ExecuteNonQuery()
Dim ActiveBanner As String = ""
Dim banner_height As Integer
Dim campaign_id As Integer
Dim imp_id As Integer
Dim banner_url As String
Dim banner_img As String
Dim banner_text As String
Dim banner_script As String
Dim banner_ID As Integer
Dim banner_width As String
'ActiveBanner = Param_activeBanners.Value()
banner_width = Param_banner_width.Value()
banner_height = Param_banner_height.Value()
If (Not IsDBNull(Param_campaign_id.Value())) Then
campaign_id = Convert.ToInt16(Param_campaign_id.Value())
End If
If (Not IsDBNull(Param_imp_id.Value())) Then
imp_id = Convert.ToInt16(Param_imp_id.Value())
End If
banner_url = Param_banner_url.Value()
banner_img = Param_banner_img.Value()
banner_text = Param_banner_text.Value()
banner_script = Param_banner_script.Value()
banner_ID = Param_banner_ID.Value()
ConnectionToFetch.Close()
ConnectionToFetch = Nothing
Param_banner_width = Nothing
Param_banner_height = Nothing
Param_campaign_id = Nothing
Param_imp_id = Nothing
Param_banner_url = Nothing
Param_banner_img = Nothing
Param_banner_text = Nothing
Param_banner_script = Nothing
Param_banner_ID = Nothing
param_adv_name_script = Nothing
If imp_page_link = "" Then
imp_page_link = " "
End If
'Dim x As Integer = parameters(9).Value
If String.IsNullOrEmpty(campaign_id) Then
campaign_id = -1
End If
If IsNothing(campaign_id) Then
campaign_id = -1
End If
If campaign_id < 1 Then 'If CInt("0" & param_campaign_id.value) < 1 Then
Return "<!-- log name='campNull' value='" & campaign_id & "' -->"
End If
If ActiveBanner = "" Then
ActiveBanner = banner_ID
ElseIf InStr("," & ActiveBanner & ",", "," & banner_ID & ",") < 1 Then
ActiveBanner = banner_ID & "," & ActiveBanner
End If
Dim strRet As String
'If request.QueryString("ads") = 1 Then
'Response.Write(" SessionID:" & Session.SessionID & " " & " disp_custom_banner " & campaign_id & "," & banner_ID & "," & adv_id & " Country=" & gCountry & " Banner=" & adv_name & " IP=" & request.ServerVariables("Remote_host"))
' End If
Dim strbuilder As New StringBuilder
If ShowAdsInfo = 1 Then
strbuilder.Append("disp_custom_banner " & campaign_id & "," & banner_ID & "," & " Country=" & imp_country & ", Banner=" & param_adv_name_script.Value())
End If
strbuilder.Append("<!-- log banner=" & banner_ID & " activeBanners=" & ActiveBanner & " -->")
strbuilder.Append("<script language='javascript' defer=defer>AdvimgBanner=" & IIf(imp_id = Nothing, 0, imp_id) & ";</script>" & vbCr)
If Len(banner_script) > 5 Then
''''''''' added for counting issue
Dim tmtmp As String = Replace(DateTime.Now.ToShortTimeString(), "PM", "")
Dim tm As String = Replace(tmtmp, "AM", "")
tm = Replace(tm, ":", "")
'''''''''
Dim max, min, RandomNum
max = 10000
min = 1
RandomNum = CStr(Int((max - min + 1) * Rnd() + min))
RandomNum = RandomNum & "-" & banner_ID
Dim ReFactor As String = Replace(banner_script, "[timestamp]", RandomNum & tm)
strbuilder.Append(Replace(ReFactor, "&cacheburst=", "&cacheburst=" & RandomNum & tm))
Return strbuilder.ToString
End If
If InStr(LCase(banner_img), ".swf") > 0 Then
Dim url_str As String = HttpContext.Current.Server.UrlEncode("http://www.xxx.com/includes/bannerhits.asp?campaign_id=" & campaign_id & "&imp_id=" & imp_id & "&URL=" & HttpContext.Current.Server.UrlEncode(banner_url))
Dim banner_str As String = "<A HREF=/includes/in_banner_hits.asp?campaign_id=" & campaign_id & "&imp_id=" & imp_id & "&URL=" & HttpContext.Current.Server.UrlEncode(banner_url) & " TARGET='_blank'>"
Dim bannersrc As String = "/updates/banners/" & banner_img
Dim concatEmbedID As String = "CAMP" & campaign_id
Dim DivNameID As String = "flashbanner" & banner_layout
Dim bannerhit As String = "http://www.xxx.com/includes/bannerhits.asp?campaign_id=" & campaign_id & "&imp_id=" & imp_id & "&URL=" & banner_url
bannerhit = HttpContext.Current.Server.UrlEncode(bannerhit)
strbuilder.Append("<div id='<%=DivNameID%>'>")
strbuilder.Append("<a href='http://www.adobe.com/go/getflashplayer'>")
strbuilder.Append("<img src='http://www.adobe.com/images/shared/download_buttons/get_flash_player.gif' alt='Get Adobe Flash player' border='0' /></a></div>")
strbuilder.Append("<script type='text/javascript' src='/includes/scripts/swfobject.js' ></script>")
strbuilder.Append("<script type='text/javascript' >")
strbuilder.Append("var so = new SWFObject(" + bannersrc + ", " + DivNameID + "," + banner_width + ", " + banner_height + ", ""6"", ""#ffffff"");")
strbuilder.Append("so.addParam(""quality"", ""autohigh "");")
strbuilder.Append("so.addParam(""bgcolor"", ""#ffffff"");")
strbuilder.Append("so.addParam(""swliveconnect"", ""false"");")
strbuilder.Append("so.addParam(""wmode"", ""transparent"");")
strbuilder.Append("so.addVariable(""clickTAG""," + bannerhit + ");")
strbuilder.Append("so.write(" + DivNameID + ");")
strbuilder.Append("</SCRIPT>")
Else
strbuilder.Append("<A HREF=/includes/in_banner_hits.asp?campaign_id=" & campaign_id & "&imp_id=" & imp_id & "&URL=" & HttpContext.Current.Server.UrlEncode(banner_url) & " TARGET='_blank'>" & _
" <IMG SRC='/updates/banners/" & banner_img & "' WIDTH='" & banner_width & "' HEIGHT='" & banner_height & "' BORDER='0' ALT='" & banner_text & "' vspace='5'></A>")
'response.write(banner_str)
End If
If Err.Number <> 0 Then
strbuilder.Append("<!--log name='err' value='" & Err.Description & _
"' Source='" & Err.Source & "' Number='" & Err.Number & "'-->")
End If
InsertCommand = Nothing
Dim strReturn As String = strbuilder.ToString
strbuilder = Nothing
Return strReturn
Catch ex As Exception
End Try
End Function
End Class
答案 0 :(得分：2)
简而言之：您应该创建，打开，使用关闭，在您使用它们的地方配置连接。
最好的方法是使用using-statement。通过不尽快关闭连接，Connection-Pool需要创建与dbms的新物理连接，这在性能方面非常昂贵。
Using conn As New SqlClient.SqlConnection(ConfigurationManager.ConnectionStrings("ConnStr").ConnectionString)
Using insertCommand As New SqlClient.SqlCommand("disp_banner_byPageName_views", conn)
insertCommand.CommandType = CommandType.StoredProcedure
' ....
End Using
End Using
未正确关闭连接时遇到的性能问题are the least。
修改：我忽略了代码中间的ConnectionToFetch.Close。
但无论如何，你应该使用try或catch的finally来关闭连接，否则在任何例外的情况下都会保持打开状态。因为你已经尝试过了一个try / catch，你可以用它来关闭它。
我不想唠叨更多，但是一个空的捕获是坏的，因为你永远不会知道什么时候引发了异常。您可能希望再次登录或至少throw在Application_Error和/或自定义错误页面或此方法的调用者处捕获它。
Try
' code here
Catch ex As Exception
' log exception and/or throw(what is always better than to intercept it)
Throw
Finally
ConnectionToFetch.Close
End Try