Getting value from a dropdown list that was populated with AJAX

Question

I had populated an ASP.net dropdown list with AJAX now I need to get the Id to store in into the database in a C# method, (I'm using LINQ)

This is my webmethod

[WebMethod]
public static ArrayList GetLanguageList()
{
    ArrayList lstArrLanguage = new ArrayList();
     IQueryable<Common.Town> myList = new SupplierBL().GetTowns();
     foreach(Common.Town t in myList)
    {
        string name = t.Name;
        string id = t.TownId.ToString();
        lstArrLanguage.Add(new ListItem(name, id));
    }

    return lstArrLanguage;
}

My test.aspx code

<script language="javascript" type="text/javascript">
    $(document).ready(function () {
        $.ajax({
            type: "POST",
            url: "test.aspx/GetLanguageList",
            data: '',
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            success: function (msg) {
                $("#ddlLanguage").empty().append($("<option></option>").val("[-]").html("Please select"));
                $.each(msg.d, function () {
                     $('#<%=ddlLanguage.ClientID%>').append($("<option></option>").val(this['Value']).html(this['Text']));
                });
            },
            error: function () {
                alert("An error has occurred during processing your request.");
            }
        });
    });
</script>

Eliza, the `GetLanguageList()` method where are you calling that from are you doing that based on a button click or form a SelectedItem in the DDL..? can you show the relevant code..? also what is Common.Town? — MethodMan, Jan 26 '13 at 15:07
when you get the DropDown list values loaded, does it have the name, Id in the list..? if so now you need to get the ID based on the selected item.. from the selected Item you could do a Split(',') and get the array[1] value correct me if I am understanding you incorrectly Eliza — MethodMan, Jan 26 '13 at 15:30
I know which data I need to get, but I don't know to to getting it into a c# method when I tried string text = ddlDropDown.SelectedValue.ToString() in gives me an error Invalid postback or callback argument — Eliza, Jan 26 '13 at 15:37
are you doing any `if(!IsPostBack)` check..? you could actually do something like this `var value = Request.Form[ddlLanguage.UniqueID];` it will get the value that was selected stored on the Server not the Client. — MethodMan, Jan 26 '13 at 15:43
what method in your code is this giving you the error..? can you get at the document level..? would really need to see where you are getting this error what code or event Eliza.. thanks — MethodMan, Jan 26 '13 at 16:05

score 7 · Accepted Answer · edited May 23 '17 at 11:47

7

You can't get selected value from DropDownList if you adding options in javaScript. You can try the following

string selectedValue = Request.Form[ddlLanguage.UniqueID];

This question may be useful also.

edited May 23 '17 at 11:47

Community

1
1

answered Jan 26 '13 at 16:09

Muhammad Hani

8,476
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score 0 · Answer 2 · answered Jan 26 '13 at 15:31

0

If you populate the value of dropdown via ajax than it can't be available on Server Side because the page doesn't postback during ajax request.

In order to get the value of dropdown in C# use below snippets :

String _value = Convert.ToString(Request[ddlLanguage.ClientID]);

Hope this will help !!

answered Jan 26 '13 at 15:31

Kundan Singh Chouhan

13,952
4
27
32

1

No, still given me the error Invalid postback or callback argument – Eliza Jan 26 '13 at 15:33

Getting value from a dropdown list that was populated with AJAX

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