CascadingDropDownList fireEvent onchange not working when parent selection changed

I changed the included sample test page to remove the autopostback from theDropDownList3 dropdown (for color). I also removed the server side onselectedindxchanged eventhandler. I wanted to give the feedback to the user all from the client side. For that effect I added the following javascript code at the end of the page:

 <script type="text/javascript">$addHandler($get('<%=DropDownList3.ClientID%>'), "change", ProvideFeedback);function ProvideFeedback(eventElement){var makeDropdown = $get('<%=DropDownList1.ClientID%>');var modelDropdown = $get('<%=DropDownList2.ClientID%>');var colorDropdown = $get('<%=DropDownList3.ClientID%>');if(colorDropdown.selectedIndex == 0){alert("Please make all your selections");}else{alert('You selected ' + makeDropdown.options[makeDropdown.selectedIndex].text + ' - ' + modelDropdown.options[modelDropdown.selectedIndex].text + ' - ' + colorDropdown.options[colorDropdown.selectedIndex].text);}} </script>

It works just fine when I change the values in the color dropdown; I get the feedback. But I am also expecting to get the feedback when I change the make or model dropdown as the onchage is internally fired for color dropdown. But I never see that handled. Everytime I change values of make or model I never get the feedback.

Why is that? What am I missing?

Thanks.

Bumping up. Could someone please respond to this thread.

Ifthis.get_element().fireEvent('onchange'); is not producing the effect I am looking for what is it for?

Thanks.

Hi Nkv321,

CascadingDropDown will compare the selected value when its onchange event is fired. If no changes , there will no further actions , so it won't call the WebService.

I hope this helps.

Best regards,

Jonathan

It's not about changing the selected value and calling the web service. It's about when the parent value changes -- child drop down items get rebound -- and then an event is fired indicating that the child dropdown value has changed.

My question is what can that event be used for? How can it be used? I tried to use it in the sample that I put forth earlier but it was not executing. For example how can I add/attach a hanlder in the page to this event?

Thanks

Hi Nkv321,

I think you can attach a Javascript to the CascadingDropDown's add_selectionChanged or add_populated. For example:

function pageLoad(){$find("CascadingDropDown's BehaviorID"). add_selectionChanged(onSelectionChanged); }

function onSelectionChanged(){//your codes here.}

add_selectionChanged //Add an event handler for the selectionChanged event

add_populated //Add an event handler for the populated event

I Hope this help.

Best regards,

Jonathan

CascadingDropDown: How to register OnChange event on client?

Hello,

I have a WebForm with three CascadingDropDown. First is the parent of second list and second is the parent of the third list. And third list has a AutoPostBack feature to populate a GridView in an UpdatePanel on the page. My challenge is clear UpdatePanel content when user change first or second lists value.

So how can I register to onChange something like event of the list on client script? Then I can use $get("UpdatePanelClientId").innerHTML="".

Regards.

Hi,

You may use the following code.

<asp:DropDownList ID="DropDownList1" runat="server" Width="170"onchange="$get('ctl00_SampleContent_UpdatePanel1').innerHTML='';"/>

You can try it on the sample website's CascadingDropDown.aspx page.

Hope this helps.