asp.net分页代码，执行偶尔会出现问题，并且执行效率非常低，请求帮助改进一下。

robake 2008-06-04 11:10:01

Public Function ReadAllNews(ByVal rPage As Integer) As String
ConnectionSQL()
ds.Clear()
SQL = "Select * from [News_Table] order by Tim desc,id asc"
mySqlAdapter = New SqlDataAdapter(SQL, Conn)
mySqlAdapter.Fill(ds, "News_Table")
Dim pagecounts As Integer = ds.Tables("News_Table").Rows.Count
Dim RCount As Integer = pagecounts

If RCount = 0 Then
ReadAllNews = "未找到新闻数据。"
Exit Function
End If

Dim i As Integer = 1

Dim pagesizes As Integer = 20
Dim curpage = rPage
Dim a, b, sa, page As Integer
a = Int(pagecounts / pagesizes)
b = pagecounts / pagesizes
If a < b Then
pagecounts = a + 1
Else
pagecounts = b
End If
If curpage < 1 Or curpage > pagecounts Then
page = 1
sa = 1
Else
page = curpage
sa = (curpage - 1) * pagesizes + 1
End If
CloseSQL()
ConnectionSQL()
ds.Clear()
mySqlAdapter = New SqlDataAdapter(SQL, Conn)
mySqlAdapter.Fill(ds, sa - 1, pagesizes, "News_Table")
For i = 0 To ds.Tables("News_Table").Rows.Count - 1
If ReadAllNews = "" Then
ReadAllNews = "<div><li class='newsl'>" & i + 1 + (rPage - 1) * 20 & ". <a href='" & ds.Tables("News_Table").Rows(i).Item("html") & "' target='_blank'>" & ds.Tables("News_Table").Rows(i).Item("topic") & "</a></li><li class='newsr'>" & Year(ds.Tables("News_Table").Rows(i).Item("tim")) & "年" & Month(ds.Tables("News_Table").Rows(i).Item("tim")) & "月" & Day(ds.Tables("News_Table").Rows(i).Item("tim")) & "日 </li></div>"
Else
ReadAllNews = ReadAllNews & vbCrLf & "<div><li class='newsl'>" & i + 1 + (rPage - 1) * 20 & ". <a href='" & ds.Tables("News_Table").Rows(i).Item("html") & "' target='_blank'>" & ds.Tables("News_Table").Rows(i).Item("topic") & "</a></li><li class='newsr'>" & Year(ds.Tables("News_Table").Rows(i).Item("tim")) & "年" & Month(ds.Tables("News_Table").Rows(i).Item("tim")) & "月" & Day(ds.Tables("News_Table").Rows(i).Item("tim")) & "日 </li></div>"
End If
Next
'====分页链接
ReadAllNews = ReadAllNews & "<div>总共 " & RCount & " 条本页 " & ds.Tables("News_Table").Rows.Count & " 条第 " & rPage & " 页/共 " & pagecounts & " 页"

If rPage > 1 Then
ReadAllNews = ReadAllNews & vbCrLf & " <a href='?page=1'>首页</a> <a href='?page=" & rPage - 1 & "'>上一页</a>"
Else
ReadAllNews = ReadAllNews & vbCrLf & " 首页上一页"
End If
If rPage < pagecounts Then
ReadAllNews = ReadAllNews & " <a href='?page=" & rPage + 1 & "'>下一页</a> <a href='?page=" & pagecounts & " '>末页</a> "
Else
ReadAllNews = ReadAllNews & " 下一页末页"
End If
ReadAllNews = ReadAllNews & "</div>"
CloseSQL()
End Funct
以上是我的函数代码，分页显示有时正常，有时出现，出现的错误有：对象未引用到实例，致命的内部错误，运行超时等，我发现，只要不调用这个函数，程序运行非常正常，效率也挺好，程序的执行时间在几十毫秒到几百之间，调用了这个函数，执行时间立即要变成几千，甚至上万毫秒，根据断点检查发现，问题在mySQLAdapter.fill这个地方，上述的代码在我的程序其他函数里也有，其他的函数运行完全正常。
请指点一下。

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