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dreamweaverMX通用分页代码研究
作者:采集员 文章来源:来源于网络 点击数: 更新时间:2005-9-10 12:59:59
dreamweaverMX已经正式发布了,Deamweaver4 + Deamweaver ULTRADEV 4 的组合使他成为当然的制做网页的首选工具,(好象做广告:) )
好了,进入正题,
我在以前做网页的分页时候都是用自己写的服务端脚本(我从不用ADO的分页),用了MX后发现在这里面用分页太方便了,不过代码也有点太长了,大家看下面的代码就可以知道。用过之后我发现里面recordset 的cursortype设为0分页竟然可以正常工作!这令我吃惊不少,分析了代码之后才发现MX 是用了一种挺笨的方法实现的,效率很低,所以大家还是用1吧:)
分析如下:


<%@LANGUAGE="VBSCRIPT" CODEPAGE="936"%>
<!--#include file="Connections/ncarcnn.asp" -->
<%
Dim Recordset1
Dim Recordset1_numRows

Set Recordset1 = Server.CreateObject("ADODB.Recordset")
Recordset1.ActiveConnection = MM_ncarcnn_STRING
Recordset1.Source = "SELECT * FROM dbo.ncarinfo"

Recordset1.CursorType = 0
'这里用0也可以正常运行,但是经过分析代码可以看出,用0的效率很低,建议用1


Recordset1.CursorLocation = 2
Recordset1.LockType = 1
Recordset1.Open()

Recordset1_numRows = 0
%>


<%
'''''''''''''''''''''''''''''''''''''
'以下为分页代码
Dim Repeat1__numRows
Dim Repeat1__index

Repeat1__numRows = 10
Repeat1__index = 0
Recordset1_numRows = Recordset1_numRows + Repeat1__numRows
%>
<%
'  *** Recordset状态, 定义状态变量

Dim Recordset1_total
Dim Recordset1_first
Dim Recordset1_last

' set the record count
Recordset1_total = Recordset1.RecordCount

' set the number of rows displayed on this page
If (Recordset1_numRows < 0) Then
  Recordset1_numRows = Recordset1_total
Elseif (Recordset1_numRows = 0) Then
  Recordset1_numRows = 1
End If

' set the first and last displayed record
Recordset1_first = 1
Recordset1_last  = Recordset1_first + Recordset1_numRows - 1

' if we have the correct record count, check the other stats 处理正确的rs
If (Recordset1_total <> -1) Then
  If (Recordset1_first > Recordset1_total) Then
    Recordset1_first = Recordset1_total
  End If
  If (Recordset1_last > Recordset1_total) Then
    Recordset1_last = Recordset1_total
  End If
  If (Recordset1_numRows > Recordset1_total) Then
    Recordset1_numRows = Recordset1_total
  End If
End If
%>
<%
' *** Recordset Stats: if we don't know the record count, manually count them处理错误的RS

If (Recordset1_total = -1) Then

  ' count the total records by iterating through the recordset
  Recordset1_total=0
  While (Not Recordset1.EOF)
    Recordset1_total = Recordset1_total + 1
    Recordset1.MoveNext
  Wend

  ' reset the cursor to the beginning
  If (Recordset1.CursorType > 0) Then
    Recordset1.MoveFirst
  Else
    Recordset1.Requery
  End If

  ' set the number of rows displayed on this page
  If (Recordset1_numRows < 0 Or Recordset1_numRows > Recordset1_total) Then
    Recordset1_numRows = Recordset1_total
  End If

  ' set the first and last displayed record
  Recordset1_first = 1
  Recordset1_last = Recordset1_first + Recordset1_numRows - 1
  
  If (Recordset1_first > Recordset1_total) Then
    Recordset1_first = Recordset1_total
  End If
  If (Recordset1_last > Recordset1_total) Then
    Recordset1_last = Recordset1_total
  End If

End If
%>
<%
Dim MM_paramName
%>
<%
' *** Move To Record and Go To Record: declare variables

Dim MM_rs
Dim MM_rsCount
Dim MM_size
Dim MM_uniqueCol
Dim MM_offset
Dim MM_atTotal
Dim MM_paramIsDefined

Dim MM_param
Dim MM_index

Set MM_rs    = Recordset1
MM_rsCount   = Recordset1_total
MM_size      = Recordset1_numRows
MM_uniqueCol = ""
MM_paramName = ""
MM_offset = 0
MM_atTotal = false
MM_paramIsDefined = false
If (MM_paramName <> "") Then
  MM_paramIsDefined = (Request.QueryString(MM_paramName) <> "")
End If
%>
<%
' *** Move To Record: handle 'index' or 'offset' parameter

if (Not MM_paramIsDefined And MM_rsCount <> 0) then

  ' use index parameter if defined, otherwise use offset parameter
  MM_param = Request.QueryString("index")
  If (MM_param = "") Then
    MM_param = Request.QueryString("offset")
  End If
  If (MM_param <> "") Then
    MM_offset = Int(MM_param)
  End If

  ' if we have a record count, check if we are past the end of the recordset
  If (MM_rsCount <> -1) Then
    If (MM_offset >= MM_rsCount Or MM_offset = -1) Then  ' past end or move last
      If ((MM_rsCount Mod MM_size) > 0) Then         ' last page not a full repeat region
        MM_offset = MM_rsCount - (MM_rsCount Mod MM_size)
      Else
        MM_offset = MM_rsCount - MM_size
      End If
    End If
  End If

  ' move the cursor to the selected record
  MM_index = 0
  While ((Not MM_rs.EOF) And (MM_index < MM_offset Or MM_offset = -1))
    MM_rs.MoveNext
    MM_index = MM_index + 1
  Wend
  If (MM_rs.EOF) Then
    MM_offset = MM_index  ' set MM_offset to the last possible record
  End If

End If
%>
<%
' *** Move To Record: if we dont know the record count, check the display range

If (MM_rsCount = -1) Then

  ' walk to the end of the display range for this page
  MM_index = MM_offset
  While (Not MM_rs.EOF And (MM_size < 0 Or MM_index < MM_offset + MM_size))
    MM_rs.MoveNext
    MM_index = MM_index + 1
  Wend

  ' if we walked off the end of the recordset, set MM_rsCount and MM_size
  If (MM_rs.EOF) Then
    MM_rsCount = MM_index
    If (MM_size < 0 Or MM_size > MM_rsCount) Then
      MM_size = MM_rsCount
    End If
  End If

  ' if we walked off the end, set the offset based on page size
  If (MM_rs.EOF And Not MM_paramIsDefined) Then
    If (MM_offset > MM_rsCount - MM_size Or MM_offset = -1) Then
      If ((MM_rsCount Mod MM_size) > 0) Then
        MM_offset = MM_rsCount - (MM_rsCount Mod MM_size)
      Else
        MM_offset = MM_rsCount - MM_size
      End If
    End If
  End If

  ' reset the cursor to the beginning
  If (MM_rs.CursorType > 0) Then
    MM_rs.MoveFirst
  Else
    MM_rs.Requery
  End If

  ' move the cursor to the selected record
  MM_index = 0
  While (Not MM_rs.EOF And MM_index < MM_offset)
    MM_rs.MoveNext
    MM_index = MM_index + 1
  Wend
End If
%>
<%
' *** Move To Record: update recordset stats

' set the first and last displayed record
Recordset1_first = MM_offset + 1
Recordset1_last  = MM_offset + MM_size

If (MM_rsCount <> -1) Then
  If (Recordset1_first > MM_rsCount) Then
    Recordset1_first = MM_rsCount
  End If
  If (Recordset1_last > MM_rsCount) Then
    Recordset1_last = MM_rsCount
  End If
End If

' set the boolean used by hide region to check if we are on the last record
MM_atTotal = (MM_rsCount <> -1 And MM_offset + MM_size >= MM_rsCount)
%>
<%
' *** Go To Record and Move To Record: create strings for maintaining URL and Form parameters

Dim MM_keepNone
Dim MM_keepURL
Dim MM_keepForm
Dim MM_keepBoth

Dim MM_removeList
Dim MM_item
Dim MM_nextItem

' create the list of parameters which should not be maintained
MM_removeList = "&index="
If (MM_paramName <> "") Then
  MM_removeList = MM_removeList & "&" & MM_paramName & "="
End If

MM_keepURL=""
MM_keepForm=""
MM_keepBoth=""
MM_keepNone=""

' add the URL parameters to the MM_keepURL string
For Each MM_item In Request.QueryString
  MM_nextItem = "&" & MM_item & "="
  If (InStr(1,MM_removeList,MM_nextItem,1) = 0) Then
    MM_keepURL = MM_keepURL & MM_nextItem & Server.URLencode(Request.QueryString(MM_item))
  End If
Next

' add the Form variables to the MM_keepForm string

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