CascadingDropDown - AJAX

Hi there,

I use three CascadingDropDown. They all get filled with SQL DB data.
In the first Dropdown you have to select the language. In the second you select a continent and in the third you select a country which belongs to the select continent from dropdown 2.
The continents in dropdown 2 are shown in the language you selected in dropdown 1.

My problem is, that it shows the countries in dropdown3 in all available languages, but I also want it to be filtered by selected language in dropdown 1.
I don't have an idea how to fix this problem.

I'm using asp.net, vb and ajax.

Please help!

Code:

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<WebMethod()> _
    Public Function GetLanguage( _
    ByVal knownCategoryValues As String, _
    ByVal category As String) As  _
    CascadingDropDownNameValue()

        Dim ConnString As String = "Data Source=tim-pc\SQLExpress;Initial Catalog=master;Integrated Security=True;"
        Dim SqlString As String = "SELECT * FROM Language"
        Dim conn As SqlConnection = New SqlConnection(ConnString)
        Dim cmd As SqlCommand = New SqlCommand(SqlString, conn)
        Dim dtrLang As SqlDataReader
        Dim languages As New List(Of CascadingDropDownNameValue)

        conn.Open()

        dtrLang = cmd.ExecuteReader

        While dtrLang.Read

            Dim strLangText As String = dtrLang("Language").ToString
            Dim strLangID As String = dtrLang("Language_ID").ToString
            languages.Add(New CascadingDropDownNameValue(strLangText, strLangID))
        End While
        Return languages.ToArray


    End Function

    <WebMethod()> _
    Public Function GetContinent( _
    ByVal knownCategoryValues As String, _
    ByVal category As String) As  _
    CascadingDropDownNameValue()

        Dim ConnString As String = "Data Source=..."
        Dim conn As SqlConnection = New SqlConnection(ConnString)
        Dim SqlString As String = "SELECT * FROM Continent WHERE Language_ID = @conti_id"
        'System.Diagnostics.Debug.Print(SqlString)
        Dim cmdFetchConti As SqlCommand = New SqlCommand(SqlString, conn)

        Dim dtrConti As SqlDataReader
        Dim kvConti As StringDictionary = CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues)

        Dim intContiId As Integer

        If Not kvConti.ContainsKey("Language") Or Not Int32.TryParse(kvConti("Language"), intContiId) Then
            Return Nothing
            'System.Diagnostics.Debug.Print("no")
        End If
        'System.Diagnostics.Debug.Print(intContiId)



        cmdFetchConti.Parameters.AddWithValue("conti_id", intContiId)
        Dim continents As New List(Of CascadingDropDownNameValue)

        conn.Open()
        dtrConti = cmdFetchConti.ExecuteReader

        While dtrConti.Read()
            Dim strContiName As String = dtrConti("Continent").ToString
            Dim strContiId As String = dtrConti("Continent_ID").ToString
            System.Diagnostics.Debug.Print(strContiName)
            System.Diagnostics.Debug.Print(strContiId)
            continents.Add(New CascadingDropDownNameValue(strContiName, strContiId))
        End While

        Return continents.ToArray

    End Function

    <WebMethod()> _
    Public Function GetCountry( _
    ByVal knownCategoryValues As String, _
    ByVal category As String) As  _
    CascadingDropDownNameValue()

        Dim ConnString As String = "Data Source=..."
        Dim conn As SqlConnection = New SqlConnection(ConnString)
        Dim SqlString As String = "SELECT * FROM Country WHERE Continent_ID = @country_id ORDER BY Country ASC"
        'System.Diagnostics.Debug.Print(SqlString)
        Dim cmdFetchCountry As SqlCommand = New SqlCommand(SqlString, conn)

        Dim dtrCountry As SqlDataReader
        Dim kvCountry As StringDictionary = CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues)

        Dim intCountryId As Integer


        If Not kvCountry.ContainsKey("Continent") Or Not Int32.TryParse(kvCountry("Continent"), intCountryId) Then
            Return Nothing
            'System.Diagnostics.Debug.Print("no")
        End If

        cmdFetchCountry.Parameters.AddWithValue("country_id", intCountryId)

        Dim countries As New List(Of CascadingDropDownNameValue)

        conn.Open()
        dtrCountry = cmdFetchCountry.ExecuteReader

        While dtrCountry.Read()
            Dim strCountryName As String = dtrCountry("Country").ToString
            Dim strCountryId As String = dtrCountry("Country_ID").ToString
            countries.Add(New CascadingDropDownNameValue(strCountryName, strCountryId))
        End While

        Return countries.ToArray
    End Function

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