Is there any way to specify the number of items to display for a RadComboBox dropdown?
I have seen there is a property to set the lookup window height, which sets the dropdown's height on popup, but nothing related to the number of items to be displayed at a time in the dropdown.
You can specify a number of items when using ShowMoreResultsBox mechanism which provides a clickable button on the drop-down list to retrieve more results when they exist.
The above link provides instructions and here is a screenshot:
Specifically, you will set the itemsPerRequest property to the value you need, which for the photo above was set to 10 and therefore populates the box that many items on it's initial request.
来源：https://stackoverflow.com/questions/13748526/radcombobox-set-number-of-items-to-display