FIX: Items loaded on demand can be added multiple times on scroll (Q3 2009 issue)

[Telerik Admin]

Hi guys,

We introduced a small problem in the Q3 2009 (2009.3.1103) in the load on demand mechanism.

Who is affected:
All scenarios where:
EnableLoadOnDemand = True and
EnableVirtualScrolling or ShowMoreResults properties are not set to True (it is False by default).

If there is a scrollbar on the dropdown and you scroll to the bottom of the items list - another request is send to the server and the items are loaded again thus multiplying the items.


Workaround:
There are several easy workarounds (choose one of them):

1. Set the _virtualScroll private member of the combobox to false. This can be done in the OnClientLoad event of the combobox:

function onClientLoadHandler(sender, e) {
    sender._virtualScroll = false;
}

2. Set the EndOfItems property to True.

• In ItemsRequested event this property is a member of the RadComboBoxItemsRequestedEventArgs class:

     

protected void RadComboBox1_ItemsRequested(object sender, RadComboBoxItemsRequestedEventArgs e)
{
    DataTable data = GetData(e.Text);

    // ...

    e.EndOfItems = true;
}

• In PageMethods mode this property is a member of the RadComboBoxData class:

[WebMethod]
public static RadComboBoxData GetCompanyNames(RadComboBoxContext context)
{
    DataTable data = GetData(context.Text);
    RadComboBoxData comboData = new RadComboBoxData();

    // ...

    comboData.Items = result.ToArray();
    comboData.EndOfItems = true;

    return comboData;
}

• In WebService mode this property is a member of the RadComboBoxData class:

[WebMethod]
public RadComboBoxData GetCompanyNames(RadComboBoxContext context)
{
    RadComboBoxData comboData = new RadComboBoxData();

    // ...

    comboData.Items = result.ToArray();
    comboData.EndOfItems = true;

    return comboData;
}

What is next
The problem is already fixed and will be available in the next Latest Internal Build and the first service pack.

We apologize for the caused inconvenience.