Webservice called two times with LoadOnDemand + EnableVirtualScrolling

[Mike Taylor]

Hi,

(I am using the 2012.3.1205.40 version.)
I think I figured out a weird issue with the RadComBox when used with LoadOnDemand + EnableVirtualScrolling.
I bind my RadComboBoxes with a WCF Webservice and has been surprised to see that it is called two times:
- when I open the drop down panel (normal) 
- but also after I selected an item.

I checked your demo and it worked as expected.
Finally I detected that it was the MaxHeight property that makes the RadCombobox to call the WCF Webservice two times.

Code:

<telerik:RadComboBox ID="ddlCustomer" runat="server" ClientIDMode="Static" EnableLoadOnDemand="true" MaxHeight="200"
    ShowMoreResultsBox="true" EnableVirtualScrolling="true" EmptyMessage="Type here ..."  >
    <WebServiceSettings Path="~/TestWS.svc" Method="LoadCustomersOnDemand" />
</telerik:RadComboBox>


<telerik:RadComboBox ID="ddlCustomer2" runat="server" ClientIDMode="Static" EnableLoadOnDemand="true"
    ShowMoreResultsBox="true" EnableVirtualScrolling="true" EmptyMessage="Type here ...">
    <WebServiceSettings Path="~/TestWS.svc" Method="LoadCustomersOnDemand" />
</telerik:RadComboBox>

The first RadCombobox calls my WCF Webservice two times, whereas the second one behaves normally (only one call).

Moreover because it is called two times, when you try to get the selectedItem after the second call, it returns null:

$find("ddlCustomer").get_selectedItem()

Can you check and confirm that?

[Mike Taylor]

UP

[Nencho]

Hello Mike,

The issue that you describe is quite strange.

I created a test page based on the provided information and code, but I was unable to replicate it.
In addition, I tried to reproduce the issue with this online demo after applying the settings that you use in your implementation - but without success.

I can suggest you find the differences between our online demo and your implementation - there has to be something specific in your code that causes the issue.

Greetings,
Nencho
the Telerik team

[Mike Taylor]

In fact this issue is dependent on this one.

[Dimitar Terziev]

Hi Mike,

Indeed the experienced behavior seems to related to the problem reported in the forum thread which you referring to. As my colleague have mentioned in the forum thread in question, this problem is already logged for fixing.

Regards,
Dimitar Terziev
the Telerik team