Introduction:
Here I will explain how to use Ajax cascading dropdownlist with database using asp.net
Description:
now I will explain how to use Ajax cascading dropdownlist in asp.net.
Here I will explain how to use Ajax cascading dropdownlist with database using asp.net
Description:
now I will explain how to use Ajax cascading dropdownlist in asp.net.
Here I already explained how to
populate dropdown based on another dropdown but now why I am explaining about
this Ajax cascading dropdownlist because if we use this Ajax cascading
dropdownlist we can get the dropdown data without any postback operation and we
don’t need to write extra code to disable dropdowns based on otherdropdown
selection all the futures available with this Ajax cascading dropdown directly
but here we need to write webservices to populate the dropdowns with
data.
Here I will explain with three dropdowns Country dropwdown, State dropdown, Region dropdown I need to populate states dropdown based on country dropdown and I need to populate region dropdown based on states dropdown for that what we have to do first design three tables in sql server with data like this
Country Table
State
Table
Region
Table
After that add AjaxControlToolkit
to your bin folder and design your aspx page like this
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<%@ Register
Namespace="AjaxControlToolkit"
Assembly="AjaxControlToolkit"
tagPrefix="ajax"
%>
<html
xmlns="http://www.w3.org/1999/xhtml">
<head
runat="server">
<title></title>
</head>
<body>
<form
id="form1"
runat="server">
<asp:ScriptManager ID="scriptmanager1"
runat="server"></asp:ScriptManager>
<div>
<table>
<tr>
<td>
Select
Country:
</td>
<td>
<asp:DropDownList ID="ddlcountry"
runat="server"></asp:DropDownList>
<ajax:CascadingDropDown ID="ccdCountry" runat="server" Category="Country" TargetControlID="ddlcountry" PromptText="Select Country" LoadingText="Loading
Countries.." ServiceMethod="BindCountryDetails" ServicePath="CascadingDropdown.asmx">
</ajax:CascadingDropDown>
</td>
</tr>
<tr>
<td>
Select
State:
</td>
<td>
<asp:DropDownList ID="ddlState"
runat="server"></asp:DropDownList>
<ajax:CascadingDropDown ID="ccdState" runat="server" Category="State" ParentControlID="ddlcountry" TargetControlID="ddlState" PromptText="Select State" LoadingText="Loading States.." ServiceMethod="BindStateDetails"
ServicePath="CascadingDropdown.asmx">
</ajax:CascadingDropDown>
</td>
</tr>
<tr>
<td>
Select
Region:
</td>
<td>
<asp:DropDownList ID="ddlRegion"
runat="server"></asp:DropDownList>
<ajax:CascadingDropDown ID="ccdRegion" runat="server" Category="Region" ParentControlID="ddlState" TargetControlID="ddlRegion" PromptText="Select Region" LoadingText="Loading Regions.." ServiceMethod="BindRegionDetails"
ServicePath="CascadingDropdown.asmx">
</ajax:CascadingDropDown>
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
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After
that add one new webservice page to your application and following
namcespaces in your webservice code behind page
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using
System.Data;
using
System.Data.SqlClient;
using
System.Collections.Generic;
using
System.Collections.Specialized;
using
System.Configuration;
using
AjaxControlToolkit;
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Here
we need to remember one point that is we need to write webmethods this format
only and use exact parameters that should be same as whatever I mentioned in
web method
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[WebMethod]
public
CascadingDropDownNameValue[]
BindCountryDetails(string knownCategoryValues,string category)
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In
this web method we have a chance to change only method name return type also
same CascadingDropDownNameValue[]
After
completion of writing namespaces and write the following code in webservice
page
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/// <summary>
/// Summary description for CascadingDropdown
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.Web.Script.Services.ScriptService()]
public
class CascadingDropdown
: System.Web.Services.WebService
{
//Database connection string
private
static string
strconnection = ConfigurationManager.AppSettings["ConnectionString"].ToString();
//database connection
SqlConnection concountry = new SqlConnection(strconnection);
public
CascadingDropdown () {
//Uncomment the following line if using designed components
//InitializeComponent();
}
/// <summary>
/// WebMethod to Populate COuntry Dropdown
/// </summary>
[WebMethod]
public
CascadingDropDownNameValue[]
BindCountryDetails(string
knownCategoryValues,string category)
{
concountry.Open();
SqlCommand cmdcountry = new SqlCommand("select
* from CountryTable", concountry);
cmdcountry.ExecuteNonQuery();
SqlDataAdapter dacountry = new SqlDataAdapter(cmdcountry);
DataSet
dscountry = new DataSet();
dacountry.Fill(dscountry);
concountry.Close();
//create list and add items in it by looping through dataset
table
List<CascadingDropDownNameValue> countrydetails = new List<CascadingDropDownNameValue>();
foreach(DataRow dtrow in
dscountry.Tables[0].Rows)
{
string
CountryID = dtrow["CountryID"].ToString();
string
CountryName = dtrow["CountryName"].ToString();
countrydetails.Add(new CascadingDropDownNameValue(CountryName,
CountryID));
}
return
countrydetails.ToArray();
}
/// <summary>
/// WebMethod to Populate State Dropdown
/// </summary>
[WebMethod]
public
CascadingDropDownNameValue[]
BindStateDetails(string knownCategoryValues,string category)
{
int
countryID;
//This method will return a StringDictionary containing the
name/value pairs of the currently selected values
StringDictionary countrydetails =AjaxControlToolkit.CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);
countryID
= Convert.ToInt32(countrydetails["Country"]);
concountry.Open();
SqlCommand cmdstate = new SqlCommand("select
* from StateTable where CountryID=@CountryID", concountry);
cmdstate.Parameters.AddWithValue("@CountryID", countryID);
cmdstate.ExecuteNonQuery();
SqlDataAdapter dastate = new SqlDataAdapter(cmdstate);
DataSet
dsstate = new DataSet();
dastate.Fill(dsstate);
concountry.Close();
//create list and add items in it by looping through dataset
table
List<CascadingDropDownNameValue> statedetails = new List<CascadingDropDownNameValue>();
foreach
(DataRow dtrow in
dsstate.Tables[0].Rows)
{
string
StateID = dtrow["StateID"].ToString();
string
StateName = dtrow["StateName"].ToString();
statedetails.Add(new CascadingDropDownNameValue(StateName,
StateID));
}
return
statedetails.ToArray();
}
/// <summary>
/// WebMethod to Populate Region Dropdown
/// </summary>
[WebMethod]
public
CascadingDropDownNameValue[]
BindRegionDetails(string knownCategoryValues,
string category)
{
int
stateID;
//This method will return a StringDictionary containing the
name/value pairs of the currently selected values
StringDictionary statedetails = AjaxControlToolkit.CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);
stateID
= Convert.ToInt32(statedetails["State"]);
concountry.Open();
SqlCommand cmdregion = new SqlCommand("select
* from RegionTable where StateID=@StateID", concountry);
cmdregion.Parameters.AddWithValue("@StateID", stateID);
cmdregion.ExecuteNonQuery();
SqlDataAdapter daregion = new SqlDataAdapter(cmdregion);
DataSet
dsregion = new DataSet();
daregion.Fill(dsregion);
concountry.Close();
//create list and add items in it by looping through dataset
table
List<CascadingDropDownNameValue> regiondetails = new List<CascadingDropDownNameValue>();
foreach
(DataRow dtrow in
dsregion.Tables[0].Rows)
{
string
RegionID = dtrow["RegionID"].ToString();
string
RegionName = dtrow["RegionName"].ToString();
regiondetails.Add(new CascadingDropDownNameValue(RegionName,
RegionID));
}
return
regiondetails.ToArray();
}
}
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