Use Ajax, jquery and jSon to get data from SQL database in asp.net and fill a listbox control

Hi,

Please go through following articals, they explain step by step:


http://www.ashishblog.com/blog/calling-database-using-jquery-ajax-and-asp-net/

http://code.google.com/p/m-jq-projects/wiki/ajaxPopulate_jQuery

http://www.daniweb.com/web-development/javascript-dhtml-ajax/threads/351614/populate-an-asp-list-box-based-on-selection-of-a-previous-list-box-using-ajax

http://www.dotnetcurry.com/ShowArticle.aspx?ID=454

Thanks

Well, I have this working to get data from a single SQL record.

My script to fill a label and textbox...
 $(document).ready(function () {
             $('#bAddDr').click(function () {
                 var u
                 u = "Help-Support.aspx?f=1&timestamp=" + (new Date()).getTime();
                 $('#Label170').text('Loading...');
                 $.getJSON(u, function (data) {
                     $('#Label170').text(data['topic']);
                     $('#tDesc').text(data['description']);
                 });
                 return false;
             });
         });

In my support page I have...
<DataContract()> Public Class Doc
        <DataMember()> Public topic As String
        <DataMember()> Public description As String
        <DataMember()> Public file As String
    End Class

Private Sub GetHelpList()
        Dim dc As New Doc
        cnn.Open()
        cmd.CommandText = "Select * from tbl_help  order by help_topic"
        dr = cmd.ExecuteReader
        If dr.HasRows Then
            Do While dr.Read()

                dc.topic = nz(dr("help_topic"))
                dc.description = nz(dr("help_description"))
                dc.file = nz(dr("help_file"))

            Loop
            doResponse(GetType(Doc), dc)
        End If
        dr.Close()
        cnn.Close()
    End Sub

    Private Sub doResponse(ByVal t As Type, ByVal o As Object)
        Dim ser As DataContractJsonSerializer
        Dim stream1 As New MemoryStream
        ser = New DataContractJsonSerializer(t)
        ser.WriteObject(stream1, o)
        stream1.Position = 0
        Dim sr As New StreamReader(stream1)
        Response.Write(sr.ReadToEnd())
    End Sub

This works good for a single item. But I want to return a list from sql with many TOPICS and then populate a ListBox on main page. Not sure how to set up and pass the DataContract or do I even need that?

instear of single object you can return list/array too.

I have tried this using a datatable and loading it into a dictionary and then serializing it to a Json string, but I am not sure how to pass it back to my main page and also on my main page how do I put the data into a listbox using jquery?

   
<DataContract()> Public Class Doc
        <DataMember()> Public serial As Integer
        <DataMember()> Public topic As String
        <DataMember()> Public description As String
        <DataMember()> Public file As String
    End Class


private sub GetHelpList()
        da.SelectCommand = cmd
        Dim dc As New Doc
        cnn.Open()
        cmd.CommandText = "Select * from tbl_help  order by help_topic"
        da.Fill(dt)
        cnn.Close()

        Dim stream As New MemoryStream()
        Dim serializer As System.Web.Script.Serialization.JavaScriptSerializer = New System.Web.Script.Serialization.JavaScriptSerializer()
        Dim rows As New List(Of Dictionary(Of String, Object))
        Dim row As Dictionary(Of String, Object)

        For Each dr As DataRow In dt.Rows
            row = New Dictionary(Of String, Object)
            For Each col As DataColumn In dt.Columns
                row.Add(col.ColumnName, dr(col))
            Next
            rows.Add(row)
        Next
        Dim JsonString = serializer.Serialize(rows)

end sub

Even if I were to  build a list array how do i serialize it and pass it back to main page and then also using jquery load it into a listbox?
Thanks