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I have an ideal in which I have an abstract class (it's called vehicle ) and Classes in the form of many heritage bikes , motorbike , car , van etc., it is basically a real Simplified version is world problem 

  Abstract class auto id; Int wheelcount; String OwnerName; Class Bike Datetime Latest Security Checks; Class motorbike-engine engine class car double engines class van double storage capacitance

I have a system that is IEnumerable & lt; Vehicle & gt; in which each of these threads is contained in Secure Singleton Class, which essentially acts as an in-memory database.

I want to make a method in my application (in singleton or separate class) which allows me to query only for a certain type of vehicle.

Initially I thought of a method: 

  Internal IEnumerable & lt; T & gt; GetVehicles & lt; T & gt; () Where T: Vehicle

In order to be able to provide a type T , which would like to retrieve that type. I know that I can use type () to do logic, but I do not know how to return my values? I am struggling with the basics of the method, and I think there should be a design pattern which means a lot more.

LINQ already has this method -: 

  var vans = vehicle. Optty Type & lt; Wan & gt; ();

To determine that an example is an example of a type that you do not need to use typeof () , you and operators use (And they can also be used with normal type): 

  if (vehicle is vane) ... if (vehicle is t) ...

or 

  variant = vehicle in the form of van; If (van! = Null) ... var example = vehicle in t; // will require t: class generic type barrier if (example! = Faucet) ... var instance = vehicle as t ?; // will be required: if the structure is the type of generic type (example! = Tap) ...


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