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Cascading Dropdownlist not retreiving values

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User-1352156089 posted

Hi All,

I cannot understand what's wrong with the below code but the dropdownlists are not populated as expected.

    <asp:DropDownList ID="ddlcontinents" runat="server" CssClass="ddlcontent"></asp:DropDownList>
    <cc1:CascadingDropDown ID="ccdddlcontinents" runat="server" 
        TargetControlID="ddlcontinents"
        PromptText="Select Continents"
        PromptValue=""
        ServicePath="ccdregioncountry.asmx"
        ServiceMethod="GetContinents"
        Category="Continent" />
 

    <asp:DropDownList ID="ddlcountries" runat="server"  CssClass="ddlcontent"> </asp:DropDownList>
        <cc1:CascadingDropDown ID="ccdddlcountries" runat="server" 
        TargetControlID="ddlcountries"   
PromptText="Select Country"
PromptValue=""
ServicePath="ccdregioncountry.asmx"
ServiceMethod="GetCountries"
Category="Country"/>

I created a webmethod as follows:

Imports System.Web
Imports System.Web.Services
Imports System.Web.Services.Protocols
Imports System.Data
Imports System.Data.SqlClient
Imports System.Configuration
Imports AjaxControlToolkit
Imports System.Collections.Generic

<WebService([Namespace]:="http://tempuri.org/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<System.Web.Script.Services.ScriptService()> _
Public Class ccdregioncountry
    Inherits System.Web.Services.WebService
    Private conString As String = System.Configuration.ConfigurationManager.ConnectionStrings("DefaultConnection").ToString()
    <WebMethod> _
    Public Function GetContinents(knownContinentValues As String, Continent As String) As CascadingDropDownNameValue()
        Dim sqlConn As New SqlConnection(conString)
        sqlConn.Open()
        Dim sqlSelect As New SqlCommand("SELECT ContinentName, ContinentId FROM Continents", sqlConn)
        sqlSelect.CommandType = System.Data.CommandType.Text
        Dim sqlAdapter As New SqlDataAdapter(sqlSelect)
        Dim myDataset As New DataSet()
        sqlAdapter.Fill(myDataset)
        sqlConn.Close()
        Dim cascadingValues As New List(Of CascadingDropDownNameValue)()
        For Each dRow As DataRow In myDataset.Tables(0).Rows
            Dim ContinentId As String = dRow("ContinentId").ToString()
            Dim ContinentName As String = dRow("ContinentName").ToString()
            cascadingValues.Add(New CascadingDropDownNameValue(ContinentName, ContinentId))
        Next
        Return cascadingValues.ToArray()
    End Function
    <WebMethod> _
    Public Function GetCountries(knownContinentValues As String, Continent As String) As CascadingDropDownNameValue()
        Dim ContinentId As Integer
        Dim continentValues As StringDictionary = CascadingDropDown.ParseKnownCategoryValuesString(knownContinentValues)
        ContinentId = Convert.ToInt32(continentValues("Continent"))
        Dim sqlConn As New SqlConnection(conString)
        sqlConn.Open()
        Dim sqlSelect As New SqlCommand("SELECT CountryName, CountryId FROM Countries WHERE ContinentId=@ContinentId", sqlConn)
        sqlSelect.CommandType = System.Data.CommandType.Text
        sqlSelect.Parameters.Add("@ContinentId", SqlDbType.Int).Value = ContinentId
        Dim sqlAdapter As New SqlDataAdapter(sqlSelect)
        Dim myDataset As New DataSet()
        sqlAdapter.Fill(myDataset)
        sqlConn.Close()
        Dim cascadingValues As New List(Of CascadingDropDownNameValue)()
        For Each dRow As DataRow In myDataset.Tables(0).Rows
            Dim CountryId As String = dRow("CountryId").ToString()
            Dim CountryName As String = dRow("CountryName").ToString()
            cascadingValues.Add(New CascadingDropDownNameValue(CountryName, CountryId))
        Next
        Return cascadingValues.ToArray()
    End Function
End Class

Thank you in advance for helping me out in double checking where is the error here.

Friday, May 22, 2015 9:07 AM

Answers

User1996603829 posted

Hi claudio,

Thanks for your post.

According to your description, you could try to fix the problem as follows:

Firstly: please add <asp:ScriptManager> tag to your page:

<asp:ScriptManager ID="ScriptManager1" runat="server" />

Secondly: please add "ParentControlID" attribute to CascadingDropDown whose ID is 'ccdddlcountries':

<cc1:CascadingDropDown ID="ccdddlcountries" runat="server"
ParentControlID="ddlcontinents"
TargetControlID="ddlcountries"
PromptText="Select Country"
PromptValue=""
ServicePath="ccdregioncountry.asmx"
ServiceMethod="GetCountries"
Category="Country" />

Thirdly: please modify the webmethod as follows, please be noticed about the parameter:

<WebMethod()>  _
     Public Function ObtenerEstadoLista(ByVal knownCategoryValues As String, ByVal category As String) As CascadingDropDownNameValue()
         Dim con As SqlConnection = New SqlConnection(strConnection)
         Dim cmd As SqlCommand = New SqlCommand
         cmd.Connection = con
         cmd.CommandType = System.Data.CommandType.Text
         cmd.CommandText = "select * from dbo.xdom_Estado"
         Dim dAdapter As SqlDataAdapter = New SqlDataAdapter
         dAdapter.SelectCommand = cmd
         con.Open
         Dim objDs As DataSet = New DataSet
         dAdapter.Fill(objDs)
         con.Close
         Dim countryNames As List(Of CascadingDropDownNameValue) = New List(Of CascadingDropDownNameValue)
         For Each dRow As DataRow In objDs.Tables(0).Rows
             Dim countryID As String = dRow("NumeroEstado").ToString
             Dim countryName As String = dRow("DescripEstado").ToString
             countryNames.Add(New CascadingDropDownNameValue(countryName, countryID))
         Next
         Return countryNames.ToArray
     End Function
     
     <WebMethod()>  _
     Public Function ObtenerMunicipioLista(ByVal knownCategoryValues As String, ByVal category As String) As CascadingDropDownNameValue()
         Dim countryID As Integer
         Dim countryValues As StringDictionary = AjaxControlToolkit.CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues)
         countryID = Convert.ToInt32(countryValues("Estado"))
         Dim con As SqlConnection = New SqlConnection(strConnection)
         Dim cmd As SqlCommand = New SqlCommand
         cmd.Connection = con
         cmd.CommandType = System.Data.CommandType.Text
         cmd.Parameters.AddWithValue("@EstadoID", countryID)
         cmd.CommandText = "select * from dbo.xdom_Municipio where ID_Estado=@EstadoID "
         Dim dAdapter As SqlDataAdapter = New SqlDataAdapter
         dAdapter.SelectCommand = cmd
         con.Open
         Dim objDs As DataSet = New DataSet
         dAdapter.Fill(objDs)
         con.Close
         Dim cityNames As List(Of CascadingDropDownNameValue) = New List(Of CascadingDropDownNameValue)
         For Each dRow As DataRow In objDs.Tables(0).Rows
             Dim cityID As String = dRow("NumeroMunicipio").ToString
             Dim cityName As String = dRow("DescripMunicipio").ToString
             cityNames.Add(New CascadingDropDownNameValue(cityName, cityID))
         Next
         Return cityNames.ToArray
     End Function
     
     <WebMethod()>  _
     Public Function ObtenerCiudadLista(ByVal knownCategoryValues As String, ByVal category As String) As CascadingDropDownNameValue()
         Dim countryID As Integer
         Dim countryValues As StringDictionary = AjaxControlToolkit.CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues)
         countryID = Convert.ToInt32(countryValues("Municipio"))
         Dim con As SqlConnection = New SqlConnection(strConnection)
         Dim cmd As SqlCommand = New SqlCommand
         cmd.Connection = con
         cmd.CommandType = System.Data.CommandType.Text
         cmd.Parameters.AddWithValue("@MunicipioID", countryID)
         cmd.CommandText = "select * from dbo.xdom_Ciudad where ID_Municipio=@MunicipioID"
         Dim dAdapter As SqlDataAdapter = New SqlDataAdapter
         dAdapter.SelectCommand = cmd
         con.Open
         Dim objDs As DataSet = New DataSet
         dAdapter.Fill(objDs)
         con.Close
         Dim cityNamestest As List(Of CascadingDropDownNameValue) = New List(Of CascadingDropDownNameValue)
         For Each dRow As DataRow In objDs.Tables(0).Rows
             Dim cityID As String = dRow("NumeroCiudad").ToString
             Dim cityName As String = dRow("DescripCiudad").ToString
             cityNamestest.Add(New CascadingDropDownNameValue(cityName, cityID))
         Next
         Return cityNamestest.ToArray
     End Function

For more information, please try to refer to the following article :
http://www.aspdotnet-suresh.com/2011/01/introduction-here-i-will-explain-how-to.html .

Best Regards,
Collina

Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM

Wednesday, May 27, 2015 4:08 AM

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Cascading Dropdownlist not retreiving values

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