c# - Make call by click on Button -

i writing app windows phone 10

i try make phone call pressing button this

windows.applicationmodel.calls.phonecallmanager.showphonecallui("phone number", "display name"); 

but have error:

error cs1069 type name 'phonecallmanager' not found in namespace 'windows.applicationmodel.calls'. type has been forwarded assembly 'windows.foundation.universalapicontract, version=2.0.0.0, culture=neutral, publickeytoken=null, contenttype=windowsruntime' consider adding reference assembly.

how can solve problem?

the error states using different namespace (windows.applicationmodel.calls). answer in error. recommending include different assembly, meaning windows.foundation.universalapicontract

edit: stated here, recommend checking requirements, there might have missed.