asp.net 数据绑定的实例代码

public partial class _default : system.web.ui.page
{
    protected string title="大家好";            //前台代码<title><%#title %></title>
    protected void page_load(object sender, eventargs e)
    {
        dataset ds = new dataset();
        string sql = configurationmanager.connectionstrings["strsql"].connectionstring;
        using (sqlconnection sqlcnn=new sqlconnection(sql))
        {
            using (sqlcommand sqlcmm=sqlcnn.createcommand())
            {
                sqlcmm.commandtext = "select * from list";
                sqldataadapter adapter = new sqldataadapter(sqlcmm);
                adapter.fill(ds);
            }
            this.radiobuttonlist1.datasource = ds.tables[0];
            this.radiobuttonlist1.datatextfield = "listname";
            this.radiobuttonlist1.datavaluefield = "id";
            //this.radiobuttonlist1.databind();
            this.checkboxlist1.datasource = ds.tables[0];
            this.checkboxlist1.datatextfield = "listname";
            this.checkboxlist1.datavaluefield = "id";
            //this.radiobuttonlist1.databind();
            this.databind();
        }            //数据绑定到radiobuttonlist,checkboxlist
        if (!ispostback)
        {
            dataset ds1 = new dataset();
            using (sqlconnection sqlcnn1 = new sqlconnection(sql))
            {
                using (sqlcommand sqlcmm1 = sqlcnn1.createcommand())
                {
                    sqlcmm1.commandtext = "select provinceid,provincename from province";
                    sqldataadapter adapter = new sqldataadapter(sqlcmm1);
                    adapter.fill(ds1);
                    this.dropdownlist1.datasource = ds1.tables[0];
                    this.dropdownlist1.datatextfield = "provincename";
                    this.dropdownlist1.datavaluefield = "provinceid";
                    this.dropdownlist1.databind();
                }
            }
        }
    }
    protected void dropdownlist1_selectedindexchanged(object sender, eventargs e)
    {
        dataset ds = new dataset();
        string str = configurationmanager.connectionstrings["strsql"].connectionstring;
        using (sqlconnection sqlcnn = new sqlconnection(str))
        {
            using (sqlcommand sqlcmm = sqlcnn.createcommand())
            {
                sqlcmm.commandtext = "select cityid,cityname from city where provinceid='" + this.dropdownlist1.selectedvalue + "'";
                sqldataadapter adapter = new sqldataadapter(sqlcmm);
                adapter.fill(ds);
                this.dropdownlist2.datasource = ds.tables[0];
                this.dropdownlist2.datatextfield = "cityname";
                this.dropdownlist2.datavaluefield = "cityid";
                this.dropdownlist2.databind();
            }
        }
    }//实现省市二级联动
}