<%@ Import NameSpace="System.Data" %>
<%@ Import NameSpace="System.Data.Oledb" %>
<Script Language="VB" runat="Server">
    '定義公共連接對象
    Dim conn As OledbConnection   '聲明一個OledbConnection對象
    '定義公共的DataAdapter對象
    Dim Da As oledbdataAdapter
    '定義公共的DataSet
    Dim ds As New DataSet()
    '定義公共的連接字符串
    Dim SQLStr As String
Sub Page_Load(Sender As Object,e As Eventargs)
  If Not Page.IsPostBack Then
    '首先建立數據連接
    conn=New OledbConnection()    '建立一個oledbConnection對象
    '設定連接字符串ConnectionString
    conn.ConnectionString="Provider=Microsoft.Jet.OLEDB.4.0;" & _
     "Data Source=" & Server.MapPath("Discuss.mdb")
    '打開連接
    conn.Open()
    '選出最近的十條記錄，按照Id的降序排列
    SQLstr="Select top 10 * from content"
    SQLstr &=" where parent=0 Order by ID desc"
    da=New OleDbDataAdapter(SQLstr,conn)
    da.Fill(ds,"head")
    '記錄當前的最后一個記錄號
       lastno.text=ds.Tables("head").rows.Item(0).Item("ID")
    '記錄當前的第一個記錄號
       dim count as integer
       count=ds.Tables("head").rows.count-1
       priorno.text=ds.Tables("head").rows.Item(count).Item("ID")
    '對于一條記錄生成一顆樹
     Tree("head")
    conn.close()    
  End If
End sub
'Tree函數采用遞歸生成樹
Sub tree(lasttab As String)  
    Dim rowid As Integer   '定義記錄錄號
    Dim content,img,aux,item,body As String 'HTML元素的ID
    Dim tr As dataRow   
    Dim tablename As String '定義樹的表名
    Response.Write("<table border=0>")
     '遍歷當前表中的記錄
   
     For Each tr In ds.Tables(lasttab).rows
         rowid=tr.Item("ID")
         '將當前記錄的子節點生成一張表
         tablename="table" & rowid
         SQLstr="Select  * from content"
         SQLstr &=" where Parent=" & rowid
         da=New OleDbDataAdapter(SQLstr,conn)
         da.Fill(ds,tablename)
        '檢測時候存在子節點，如果存在繼續使用遞歸來生成樹，如果不存在，退出遞歸
       If ds.Tables(tablename).rows.count=0 then
          '如果當前節點已經是葉節點，顯示當前節點，退出遞歸
          Response.Write("<tr>")
          Response.Write("<td>")
          img="img" & rowid
          item="Item" & rowid
          Content="content" & rowid
          body="body" & rowid
          Response.Write("<p align='right'><img id=" &Img & " src='minus.gif' WIDTH='9' HEIGHT='9'></p>")
          Response.Write("</td>")
          Response.Write("<td id=" & item & " language='JavaScript' onMouseUp='turnout(" & body & ");' style='CURSOR: hand'><font  face='楷體_GB2312' size='2'><strong>" & tr.Item("subject") & "——" & tr.Item("Sender") & tr.Item("SendDate") & "</strong></font></a></td>")
        Response.Write (" </tr>")
        Response.Write("<tr>")
        response.write("<td colspan=2 id=" & body & " style='DISPLAY: none'>" )
        Response.Write("<table border=0 bgcolor='grey'>")
        Response.Write("<tr><td></td>")
        Response.Write("<td><font size=1>" & tr.Item("body") &"</font></td>")
        Response.Write("</tr>")
 Response.Write("<tr><td></td>")
        Response.Write("<td><font size=1><a href=mailto:" & tr.Item("Email") & ">寄信給作者  </a>")
        Response.Write("<a href=post.aspx?ID=" & Tr.Item("id") & "&subject=" & tr.item("subject") & ">回復此文</a></font></td>")
        Response.Write("</tr>")
        Response.Write("</table>")
        Response.Write("</td></tr>")
        '如果不是葉節點，則繼續遞歸顯示
       Else 
         content="content" & rowid
         img="img" & rowid
         aux="Aux" & rowid
         body="body" & rowid
         item="Item" & rowid
         '顯示信息頭     
      Response.Write("<tr>")
      Response.Write("<td language='JavaScript' onMouseUp='turnit("& Content &","& Img &"," & Aux & ");' style='CURSOR: hand'>")
        Response.Write("<p align='right'><img id=" &Img & " src='plus.gif' WIDTH='9' HEIGHT='9'></p>")
        Response.Write("</td>")
        Response.Write("<td id=" & item & " language='JavaScript' onMouseUp='turnout(" & body & ");' style='CURSOR: hand'><font  face='楷體_GB2312' size='2'><strong>" & tr.Item("subject") & "——" & tr.Item("Sender") & tr.Item("SendDate") & "</strong></font></a></td>")
        Response.Write (" </tr>")
        Response.Write("<tr>")
        response.write("<td colspan=2 id=" & body & " style='DISPLAY: none'>")
        Response.Write("<table border=0 bgcolor='grey'>")
        Response.Write("<tr><td></td>")
        Response.Write("<td><font size=1>" & tr.Item("body") &"</font></td>")
        Response.Write("</tr>")
        Response.Write("<tr><td></td>")
        Response.Write("<td><font size=1><a href=mailto:" & tr.Item("Email") & ">寄信給作者  </a>")
        Response.Write("<a href=post.aspx?ID=" & Tr.Item("id") & "&subject=" & tr.item("subject") & ">回復此文</a></font></td>")
        Response.Write("</tr>")
        Response.Write("</table>")
        Response.Write("</td></tr>")
        Response.Write("<tr>")
        Response.Write("<td id=" & Aux & "  style='DISPLAY: none'></td>")
        Response.Write ("<td id=" & Content & " style='DISPLAY: none'>")
        '將遞歸深度加深
        tree(tablename)
          Response.Write("</tr>")
    End If
         next
        Response.Write("</Table>")
End Sub
Sub prior_click(Sender As object,e As Eventargs)
    '首先建立數據連接
    conn=New OledbConnection()    '建立一個oledbConnection對象
    '設定連接字符串ConnectionString
    conn.ConnectionString="Provider=Microsoft.Jet.OLEDB.4.0;" & _
     "Data Source=" & Server.MapPath("Discuss.mdb")
    '打開連接
    conn.Open()
    '選出最近的十條記錄，按照Id的降序排列
    SQLstr="Select top 10 * from content"
    SQLstr &=" where parent=0 "
    SQLstr &=" and ID<" & priorno.text
    SQLstr &=" Order by ID desc"
    da=New OleDbDataAdapter(SQLstr,conn)
    da.Fill(ds,"head")
    if ds.Tables("head").rows.count=0 then
      Response.Write("已經到了第一頁!")
    Else
    '記錄當前的最后一個記錄號
       lastno.text=ds.Tables("head").rows.Item(0).Item("ID")
    '記錄當前的第一個記錄號
       dim count as integer
       count=ds.Tables("head").rows.count-1
       priorno.text=ds.Tables("head").rows.Item(count).Item("ID")
    '對于一條記錄生成一顆樹
     Tree("head")
    End If
    conn.close()    
End Sub
Sub Next_Click(Sender As object,e As Eventargs)
    '首先建立數據連接
    conn=New OledbConnection()    '建立一個oledbConnection對象
    '設定連接字符串ConnectionString
    conn.ConnectionString="Provider=Microsoft.Jet.OLEDB.4.0;" & _
     "Data Source=" & Server.MapPath("Discuss.mdb")
    '打開連接
    conn.Open()
    '選出最近的十條記錄，按照Id的降序排列
    SQLstr="Select top 10 * from content"
    SQLstr &=" where parent=0 "
    SQLstr &=" and ID>" & lastno.text
    SQLstr &=" Order by ID Asc"
    da=New OleDbDataAdapter(SQLstr,conn)
    da.Fill(ds,"head")
    if ds.Tables("head").rows.count=0 then
      Response.Write("已經到了最后一頁!")
    Else
     '記錄當前的最后一個記錄號
         Dim count as integer
         count=ds.Tables("head").rows.count-1
       lastno.text=ds.Tables("head").rows.Item(count).Item("ID")
    '記錄當前的第一個記錄號
       priorno.text=ds.Tables("head").rows.Item(0).Item("ID")
       '對于一條記錄生成一顆樹
    Tree("head")
    End If
    conn.close()    
End Sub
</Script>
<script lanuage="javascript">
function turnit(ss,ii,aa)
{
 if (ss.style.display=="none") 
  {ss.style.display="";
   aa.style.display="";
   ii.src="minus.gif";
 }
 else
  {ss.style.display="none"; 
   aa.style.display="none";
   ii.src="plus.gif";}
}
function turnout(bb)
{
 if (bb.style.display=="none") 
  {
    bb.style.display="";
   } 
 else
{
  bb.style.display="none";
}
}
</script>
<Html>
<Head>
<title>歡迎進入論壇!</Title>
</Head>
<Body bgcolor="lightgrey">
<Form runat="Server">
<asp:linkbutton id="prior" text="上一頁"
      OnClick="prior_click" runat="Server"/>
<asp:linkbutton id="nxt" text="下一頁" 
      OnClick="next_click" runat="Server"/>
<asp:Textbox id="lastno" visible=false runat="server" />
<asp:textbox id="priorno" visible=false runat="Server" />
</Form>
</Body>
</Html>