xamarin forms -get the imei number

Question

hi,

 

I want find the imei number of the device in xamarin forms .I have tryed the following solution but nothing is happen 

 

 This is serviceImei which implement the  interface IServiceImei containg one function

 

And Mianpage having the following code 

 

  when i exceute this nothing is happen.

plz provide some suggestion.