Hi Sebastian! Thanks your answer so kind of you. I download your code to my local project and debug your demo ajax by fiddler, I found that , The first ajax call http://demos.telerik.com/kendo-ui/service/Orders/ValueMapper return nothing, and the second ajax call
return a value of page data, one property is _count and other property is page data,I fix my code of back-end and return json data like your demo's structure,but I meet a problem again, I don't know how to bind data to dropdown list if my json data is like your demo's structure,
Here is my json data as image shows. hope your help, thanks again!