一、取得數(shù)據(jù)表 i 行 j 列的值   

     //建立并打開數(shù)據(jù)庫連接
    oledbconnection conn=new oledbconnection();
    conn.connectionstring=strconnectionstring;//strconnectionstring為數(shù)據(jù)庫連接字符串
    conn.open();

    string sql="select * from newsclass order by classid desc";
    string x; 
    dataset ds=new dataset();
    oledbdataadapter da=new oledbdataadapter(sql,conn);  
    da.fill(ds,"newstable");
    datatable dt=ds.tables["newstable"]; 
    x=dt.rows[i][1].tostring()//數(shù)據(jù)表i行j列的值  
    conn.close();

二、將數(shù)據(jù)讀入dropdownlist

（1）  dropdownlist中添加數(shù)據(jù)

  //建立并打開數(shù)據(jù)庫連接
    oledbconnection conn=new oledbconnection();
    conn.connectionstring=strconnectionstring;//strconnectionstring為數(shù)據(jù)庫連接字符串
    conn.open();

    string sql="select * from newsclass order by classid desc";
    //建立數(shù)據(jù)集
    dataset ds=new dataset();
    oledbdataadapter da=new oledbdataadapter(sql,conn);  
    da.fill(ds,"newstable");
    this.dropdownlist1.datasource=ds;
    this.dropdownlist1.datatextfield = "classname";//text值
    this.dropdownlist1.datavaluefield = "classid";//value值
    this.dropdownlist1.databind();
    
    conn.close();

（2）選中dropdownlist的某項

this.dropdownlist1.items.findbyvalue(dr["classid"].tostring().trim()).selected=true;//dr為datarow

三、分類編碼檢索出相應(yīng)的分類名稱并在datagrid中顯示

（1）.aspx中的代碼（classid為分類編碼）：

    <asp:templatecolumn headertext="類 別">
         <itemtemplate>
          <asp:label id=lblclass runat="server" text='<%# getclassname(convert.toint32(databinder.eval(container, "dataitem.classid"))) %>'>
          </asp:label>
         </itemtemplate>
        </asp:templatecolumn>

（2）c#代碼：

 /// <summary>
  /// "分類"列根據(jù)數(shù)字返回文字
  /// </summary>
  /// <param name="ispassed"></param>
  /// <returns></returns>
  public string  getclassname(int classid)
  {
   oledbconnection conn=new oledbconnection();
   conn.connectionstring=strconnectionstring;
   conn.open();

   string sql="select * from newsclass where classid="+classid;
   dataset ds=new dataset();
   oledbdataadapter da=new oledbdataadapter(sql,conn);
   da.fill(ds,"classtable");
   datatable dt=ds.tables["classtable"];
   string strclassname=dt.rows[0]["classname"].tostring();
   conn.close();

   return strclassname;//返回 classid對應(yīng)的classname
  }