DropDownHeight Autosize

[Thomas]

Is there a way to have the DropDownList DropDownHeight be determined on drop down ("popup opened")?

[Thomas]

Just figured out a way:

private void CalculateSize(RadDropDownList list)
        {
            float height = 0;

            for (int x = 0; x < list.Items.Count(); x++)
            {
                height += list.Items[x].MeasuredSize.Height;
            }

            height += 2;
            height = (height > list.DropDownMaxSize.Height) ? list.DropDownMaxSize.Height : (int)height;

            if (list.DropDownHeight != height)
            {
                list.DropDownHeight = (int)height;

                // Refresh?
                list.CloseDropDown();
                list.ShowDropDown();
            }
        }

[Thomas]

Call that function from "PopupOpened" or PopupOpening

[Stefan]

Hello Thomas,

I can confirm that the PopupOpened/PopupOpening events are suitable for the purpose. Since by this time the drop down height is already set, the "refresh" is needed. 

I would also like to mention that while your function will work when the AutoSizeItems = true, for the rest of the cases one can use the following property to retrieve the item's height:

radDropDownList1.DropDownListElement.ItemHeight

I hope that you find this information useful.

Regards,
Stefan
Telerik