RadComboBox selected value is empty

Question

I get the SelectedValue = "" when i click on My button .

My aspx :

<telerik:RadComboBox ID="ddl_contactList" runat="server" AutoPostBack="True" CausesValidation="False"
            CollapseDelay="0" Culture="ar-EG" ExpandDelay="0" Filter="StartsWith" ItemsPerRequest="10"
            MarkFirstMatch="true" Skin="Outlook" EnableAutomaticLoadOnDemand="True" EmptyMessage="-New Menu-"
            ShowMoreResultsBox="True" OnSelectedIndexChanged="ddl_contactList_SelectedIndexChanged"
            EnableItemCaching="false" EnableLoadOnDemand="True" EnableVirtualScrolling="True">
        </telerik:RadComboBox>

My .cs :

 private void BindContactLists(int year, int main_code)
        {
            ddl_contactList.Items.Clear();
            DataTable dt = ContactList.GetContactListsByDep(year, main_code);
            ddl_contactList.DataSource = dt;
            ddl_contactList.DataTextField = "list_desc";
            ddl_contactList.DataValueField = "list_code";
            ddl_contactList.DataBind();

        }

I call it in the page load because when I call it in the !Page.Ispostback, I get the following error:

There is no assigned data source. Unable to complete callback request.

How can I fix this problem? Right now:

ddl_contactList.Text == "MySelectedItemText"

but

selectedValue == "" and selectedItem == ""

Could you provide the class for ContactList too, or at least a sample return from ContactList.GetContactListsByDep(year, main_code)? — DanM7, Sep 26 '12 at 16:58
Could you post more of your code here? Possible the whole load event? — Cruril, Sep 27 '12 at 19:38

score 8 · Accepted Answer · answered Oct 15 '12 at 19:20

8

Move your call to BindContactLists() from the Page_Load() method to the Page_Init() method. This allows the control to be setup for ViewState binding later in the page lifecycle, and allow proper population of the SelectedValue property.

answered Oct 15 '12 at 19:20

lukiffer

11,025
8
46
70

score 3 · Answer 2 · answered Sep 26 '12 at 17:56

3

It's normal because you re-bind your datas => so you erase your selected value

I suggest you to set your block in !IsPostBack => you don't erase when you post

In PageLoad

if(! IsPostBack)
{

           ddl_contactList.Items.Clear();
            DataTable dt = ContactList.GetContactListsByDep(year, main_code);
            ddl_contactList.DataSource = dt;
            ddl_contactList.DataTextField = "list_desc";
            ddl_contactList.DataValueField = "list_code";
            ddl_contactList.DataBind();


}

And you persist your control with ViewState

Set EnableViewState="true"

answered Sep 26 '12 at 17:56

Aghilas Yakoub

28,516
5
46
51

I try this but i get the following error : `There is no assigned data source. Unable to complete callback request` – Anyname Donotcare Sep 27 '12 at 07:09
Databound controls aren't entirely stored in ViewState, and the control would not be databound when `IsPostBack` is true. – lukiffer Oct 15 '12 at 19:23

score 1 · Answer 3 · answered Oct 21 '12 at 10:50

1

make sure your datasource like dataset or datatable fill when page load or init fire

answered Oct 21 '12 at 10:50

soheil bijavar

1,213
2
10
18

RadComboBox selected value is empty

3 Answers3

Linked