通过下拉DropDownList来筛选新闻显示表(有新闻类别名称)

后台:

protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            string SQL_SELECT_Type = "SELECT * FROM NewsType";
            //使用using确保释放数据库连接
            //连接字符串存放在Web.Config文件中便于修改
            using (SqlConnection conn = new SqlConnection(ConfigurationSettings.AppSettings["ConnectionString"]))
            {
                SqlDataAdapter dataAdapter = new SqlDataAdapter(SQL_SELECT_Type, conn);
                DataSet ds = new DataSet();
                dataAdapter.Fill(ds);
                //设置下拉列表的数据源与文本域、值域
                dropDownList.DataSource = ds;
                dropDownList.DataTextField = "ClassName";
                dropDownList.DataValueField = "ClassID";
                dropDownList.DataBind();
            }
        }
    }
    protected void button_Click(object sender, EventArgs e)
    {
        string SQL_SELECT_News = "SELECT Title,UpdateTime,ClassName from News,NewsType where News.ClassID=NewsType.ClassID and NewsType.ClassID = {0}";
        using (SqlConnection conn = new SqlConnection(ConfigurationSettings.AppSettings["ConnectionString"]))
        {
            //用下拉列表选择的值替换掉SQL语句中的待定字符{0}
            SqlDataAdapter dataAdapter = new SqlDataAdapter(string.Format(SQL_SELECT_News, dropDownList.SelectedValue), conn);
            DataSet ds = new DataSet();
            dataAdapter.Fill(ds);
            dataGrid.DataSource = ds;
            dataGrid.DataBind();
        } 

前台:

<asp:DropDownList id="dropDownList" runat="server"></asp:DropDownList>
 <asp:Button id="button" runat="server" Text="Button" OnClick="button_Click"></asp:Button>
 <asp:DataGrid id="dataGrid" runat="server" AutoGenerateColumns="False">
        <Columns>
            <asp:BoundColumn DataField="Title" HeaderText="新闻标题"></asp:BoundColumn>
            <asp:BoundColumn DataField="UpdateTime" DataFormatString="{0:d}" HeaderText="发表时间"></asp:BoundColumn>
            <asp:BoundColumn DataField="ClassName" HeaderText="新闻类型"></asp:BoundColumn>
        </Columns>
    </asp:DataGrid>

高级功能在:http://www.microsoft.com/china/community/Column/93.mspx