ASP.NET 2.0中随机读取Access数据库记录-技术开发专区

ASP.NET 2.0中随机读取Access数据库记录

作者：孟宪会编辑：晓徐 2007-04-21 22:38

【IT168 技术文档】由于使用ADO访问Access数据库会有缓存，这在随机提取数据库数据时，例如：sql="select top 10 Title,objectGuid from Document Order By Rnd(id)"，将得不到随机记录，下面的例子可以克服这一缺陷，实现数据库的随机读取。

C#:

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

  protected void Page_Load( object sender, EventArgs e )
  ...{
    Random rnd = new Random(unchecked((int)DateTime.Now.Ticks));
    int intRandomNumber = rnd.Next();
    string ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|
        \aspxWeb.mdb;Persist Security Info=True";
    string sql = "select top 10 Title,objectGuid from Document  Order By  
        Rnd(" + (-1 * intRandomNumber) + "*id)";
    System.Data.OleDb.OleDbConnection cn = new System.Data.OleDb.OleDbConnection(ConnectionString);
    cn.Open();
    System.Data.OleDb.OleDbCommand cmd = new System.Data.OleDb.OleDbCommand(sql, cn);
    System.Data.OleDb.OleDbDataReader dr = c
         md.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
    GridView1.DataSource = dr;
    GridView1.DataBind();
    dr.Close();
    cmd.Dispose();
    cn.Dispose();
    cn = null;

  }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
  <title>随机读取Access数据库记录</title>
</head>
<body>
  <form id="form1" runat="server">
    <div>
      <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
        <Columns>
          <asp:HyperLinkField DataNavigateUrlFields="objectGuid" HeaderText="文章" 
DataTextField="Title"
            DataNavigateUrlFormatString="http://dotnet.aspx.cc/article/{0}/read.aspx" />
        </Columns>
      </asp:GridView>
    </div>
  </form>
</body>
</html>

关注我们