asp.net data Binding Instance Code _ Practical Tips

Copy Code code as follows:

public partial class _default:system.web.ui.page
{
Protected string title= "everyone good"; Front Code <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 ();
}//Data binding to 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 ();
}
}
}//realize two-level linkage between provinces and cities
}