Asp. NET implementation of the dropdown box two-level linkage components

Asp.net| pull Down

Namespace WEBAPPLICATIONDLH
{
Using System;
Using System.Data;
Using System.Drawing;
Using System.Web;
Using System.Web.UI.WebControls;
Using System.Web.UI.HtmlControls;
Using System.Data.SqlClient;
Using Db;
<summary>
A summary description of area.
</summary>
public class Area:System.Web.UI.UserControl
{
protected System.Web.UI.WebControls.DropDownList ddlprovince;
protected System.Web.UI.WebControls.DropDownList ddlcity;
public string Strprovince
{
Get
{
return ddlProvince.SelectedItem.Value;
}
Set
{
DdlProvince.SelectedItem.Value = Value;
}
}
public string strcity
{
Get
{
return ddlCity.SelectedItem.Value;
}
Set
{
DdlCity.SelectedItem.Value = Value;
}
}
private void Page_Load (object sender, System.EventArgs e)
{
if (! IsPostBack)
{
Ddlprovincebind ();
DdlCity.Items.Insert (0, "-Please select City-");
}
}
private void Ddlprovincebind ()
{
Db.area Myarea = new Db.area ();
SqlDataReader dr = Myarea.getallprovince ();
if (Dr. Read ())
{
Ddlprovince.datasource = Dr;
Ddlprovince.datatextfield = "province";
Ddlprovince.datavaluefield = "province";
Ddlprovince.databind ();
DdlProvince.Items.Insert (0, "-Please select Province-");
}
}
Code generated #region the Web forms Designer
Override protected void OnInit (EventArgs e)
{
//
CodeGen: This call is required for the ASP.net Web forms Designer.
//
InitializeComponent ();
Base. OnInit (e);
}

///<summary>
///The designer supports the method you want-do not modify the contents of this method using the Code Editor
///.
///</summary>
private void InitializeComponent ()
{
This.ddlProvince.SelectedIndexChanged + = new System.EventHandler (this.ddlprovince_selectedindexchanged);
this. Load + = new System.EventHandler (this. Page_Load);
}
#endregion
private void Ddlprovince_selectedindexchanged (object sender, System.EventArgs e)
{
if ( DdlProvince.SelectedItem.Value = = "-Please select Province-")
{
DdlCity.Items.Clear ();
DdlCity.Items.Insert (Ddlprovince.selectedindex, "-Please select City-");
}
Else
{
Db.area myarea = new Db.area ();
SqlDataReader dr = Myarea.getallcitywhereprovince (DdlProvince.SelectedItem.Value);
if (Dr. Read ())
{
Ddlcity.datasource = dr;
Ddlcity.datatextfield = "City";
Ddlcity.datavaluefield = "ID";
Ddlcity.databind ();
}
}
}
}
}

=============================================================〉
Using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration; A summary description of the
namespace Db
{
///<summary>
///area.
///</summary>
public class Area:base
{
Public area ()
{
//
//TODO: Add constructor logic here
// br>}
Public SqlDataReader getallprovince ()
{
Strsp = "Sp_area_selectall";
Drselectall (STRSP);
Return Dr;
}
Public SqlDataReader getallcitywhereprovince (string a)
{
conn = new SqlConnection ( configurationsettings.appsettings["DSN"]);
cmd = new SqlCommand ("Sp_area_selectallwhereprovince", conn);
Cmd.commandtype = CommandType.StoredProcedure;
Cmd. Parameters.Add ("@Province", sqldbtype.varchar,50). Value = A.tostring ();
Conn. Open ();
Dr = cmd. ExecuteReader (commandbehavior.closeconnection);
Return Dr;
}
}
}

=====================================================〉
if exists (SELECT * from dbo.sysobjects WHERE id = object_id (N ' [dbo].[ Sp_area_selectall] and OBJECTPROPERTY (ID, N ' isprocedure ') = 1)
drop procedure [dbo]. [Sp_area_selectall]
Go
if exists (SELECT * from dbo.sysobjects WHERE id = object_id (N ' [dbo].[ Sp_area_selectallwhereprovince] and OBJECTPROPERTY (ID, N ' isprocedure ') = 1)
drop procedure [dbo]. [Sp_area_selectallwhereprovince]
Go
if exists (SELECT * from dbo.sysobjects WHERE id = object_id (N ' [dbo].[ Area] ') and OBJECTPROPERTY (ID, N ' isusertable ') = 1)
drop table [dbo]. [Area]
Go
CREATE TABLE [dbo]. [Area] (
[ID] [int] not NULL,
[Province] [varchar] (m) COLLATE chinese_prc_ci_as NULL,
[City] [varchar] (m) COLLATE chinese_prc_ci_as NULL,
Other [varchar] (m) COLLATE chinese_prc_ci_as NULL
) on [PRIMARY]
Go
SET QUOTED_IDENTIFIER ON
Go
SET ANSI_NULLS on
Go
CREATE PROCEDURE Sp_area_selectall
As
SELECT DISTINCT Province
From area
Order by province
Return
Go
SET QUOTED_IDENTIFIER OFF
Go
SET ANSI_NULLS on
Go
SET QUOTED_IDENTIFIER ON
Go
SET ANSI_NULLS on
Go
CREATE PROCEDURE sp_area_selectallwhereprovince
@Province varchar (50)
As
SELECT area.*
From area
WHERE (province = @Province)
Return
Go
SET QUOTED_IDENTIFIER OFF
Go
SET ANSI_NULLS on
Go
================================================〉
Using System;
Using System.Data;
Using System.Data.SqlClient;
Using System.Configuration; Namespace Db
{
<summary>
A summary description of Base.
</summary>
public class Base
{
Public Base ()
{
//
TODO: Add constructor logic here
//
}
protected string con = configurationsettings.appsettings["DSN"];
Protected SqlConnection conn;
protected SqlCommand cmd;
protected SqlDataReader Dr;
protected string strsp;
Protected SqlDataReader Drselectall (string strsp)
{
conn = new SqlConnection (Con);
cmd = new SqlCommand (strsp,conn);
Cmd.commandtype = CommandType.StoredProcedure; Conn. Open ();
Dr = cmd. ExecuteReader (commandbehavior.closeconnection);
Return Dr;
}//returns a SqlDataReader}
}