if,return method

Question

 Hi, I was wondering if there a way to make it so if something other than int or double is input, it gives an error message.

This is what I got so far: 

 

public static void FirstInput()

{
Console.WriteLine("F to C");
Console.Write("Enter number : ");
double.TryParse(Console.ReadLine(), out fromF);

}

 

//and below is the coding that I got from a friend 

Is there a way to integrate those two codes? 

if (int.tryParse(Console.ReadLine(), out res))

return res;

console.WriteLine("Error, can't convert, try again");

return GetInteger();

 

 

Thank you!