index.aspx
来自「《ASP.NET C#程序设计案例教程》」· ASPX 代码 · 共 64 行
ASPX
64 行
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.OleDb" %>
<Script Language="VB" Runat="Server">
Sub Page_Load(Sender As Object,E as Eventargs)
Dim VisitNum As Long
'下面要判断是刚刚打开页面,还是重新打开页面
If Session("Visited") Is Nothing Then
'这表示客户刚刚打开页面
VisitNum=GetVisitNum()+1 '读取原有访问次数并加1
Session("Visited")=True '更新访问标志
Call AddVisitNum() '调用过程,令访问次数加1
Else
'这表示客户刷新页面,或者从别的页面返回
VisitNum=GetVisitNum() '读取原有访问次数
End If
message.Text="您是第" & VisitNum & "位访客" '显示访问次数
End Sub
'该函数用来读取原有访问次数
Function GetVisitNum() As Long
Dim conn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Server.Mappath("temp.mdb"))
Dim strSql As String = "Select * From counters"
Dim cmd As New OleDbCommand(strSql, conn) '建立Command对象
conn.Open
Dim dr As OleDbDataReader = cmd.ExecuteReader() '建立DataReader对象
'下面判断数据库中是否已经有记录,如有,则读取记录;如没有,则添加一条记录
If dr.HasRows=True Then '如有记录,dr.HasRows会返回True
dr.Read() '读取一条记录
GetVisitNum=dr.Item("VisitNum") '返回原有访问次数
Else
GetVisitNum=0 '返回原有访问次数
Call InitialVisitNum() '调用过程添加一条记录
End If
conn.Close
End Function
'该过程用来添加初始记录
Sub InitialVisitNum()
Dim conn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Server.Mappath("temp.mdb"))
Dim strSql As String = "Insert Into counters(VisitNum) Values(0)"
Dim cmd As New OleDbCommand(strSql, conn)
conn.Open
cmd.ExecuteNonQuery()
conn.Close
End Sub
'该过程用来给访问次数加1
Sub AddVisitNum()
Dim conn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Server.Mappath("temp.mdb"))
Dim strSql As String = "Update counters Set VisitNum = VisitNum + 1"
Dim cmd As New OleDbCommand(strSql, conn)
conn.Open
cmd.ExecuteNonQuery()
conn.Close
End Sub
</Script>
<html>
<body>
<h3 align="center">个人主页</h3>
<asp:Label id="message" runat="server"/>
</body>
</html>
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