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On selecting value not change in child DropdownList

mayank prajapati

mayank prajapati
Feb 18 2015 7:13 AM
587
I have created three tables CountryTable(CountryID,CountryName), StateTable(StateID(PK),StateName,CountryID(FK)),RegionTable(RegionID(PK),RegionName,StateID(FK)) 
 
 I am getting Country Name list in dropdownlist but not all other.. 
 
web.config file
_______________________ 
<connectionStrings>
<add name="DbContext" connectionString="Server=MAYANK; Database=CounrtyDB; User ID=sa; Password=123" providerName="System.Data.SqlClient"/>
</connectionStrings>
 
Index.aspx
 <html>
<head></head> 
<body>
<form id="form1" runat="server">
<div>
<table>
<tr>
<td>
Select Country:
</td>
<td>
<asp:DropDownList ID="ddlCountry" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddlCountry_SelectedIndexChanged"></asp:DropDownList>
</td>
</tr>
<tr>
<td>
Select State:
</td>
<td>
<asp:DropDownList ID="ddlState" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddlState_SelectedIndexChanged"></asp:DropDownList>
</td>
</tr>
<tr>
<td>
Select Region:
</td>
<td>
<asp:DropDownList ID="ddlRegion" runat="server"></asp:DropDownList>
</td>
</tr>
</table>
</div>
</form>
</body>
</html> 
index.aspx.cs
 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.Sql;
using System.Data.SqlClient;
using System.Configuration;
namespace CountryApplication
{
public partial class Home : System.Web.UI.Page
{
string strConnection = ConfigurationManager.ConnectionStrings["DbContext"].ConnectionString;
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
BindContrydropdown();
}
}
protected void BindContrydropdown()
{
//conenction path for database
SqlConnection con = new SqlConnection(strConnection);
con.Open();
SqlCommand cmd = new SqlCommand("select * from CountryTable", con);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
con.Close();
ddlCountry.DataSource = ds;
ddlCountry.DataTextField = "CountryName";
ddlCountry.DataValueField = "CountryID";
ddlCountry.DataBind();
ddlCountry.Items.Insert(0, new ListItem("--Select--", "0"));
ddlState.Items.Insert(0, new ListItem("--Select--", "0"));
ddlRegion.Items.Insert(0, new ListItem("--Select--", "0"));
}
protected void ddlCountry_SelectedIndexChanged(object sender, EventArgs e)
{
int CountryID = Convert.ToInt32(ddlCountry.SelectedValue);
SqlConnection con = new SqlConnection(strConnection);
con.Open();
SqlCommand cmd = new SqlCommand("select * from StateTable where CountryID=" + CountryID, con);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
con.Close();
ddlState.DataSource = ds;
ddlState.DataTextField = "StateName";
ddlState.DataValueField = "StateID";
ddlState.DataBind();
ddlState.Items.Insert(0, new ListItem("--Select--", "0"));
if (ddlState.SelectedValue == "0")
{
ddlRegion.Items.Clear();
ddlRegion.Items.Insert(0, new ListItem("--Select--", "0"));
}
}
protected void ddlState_SelectedIndexChanged(object sender, EventArgs e)
{
int StateID = Convert.ToInt32(ddlState.SelectedValue);
SqlConnection con = new SqlConnection(strConnection);
con.Open();
SqlCommand cmd = new SqlCommand("select * from RegionTable where StateID=" + StateID, con);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
con.Close();
ddlRegion.DataSource = ds;
ddlRegion.DataTextField = "RegionName";
ddlRegion.DataValueField = "RegionID";
ddlRegion.DataBind();
ddlRegion.Items.Insert(0, new ListItem("--Select--", "0"));
}
}
} 
 

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