Question

I am using LinqPad and in that I was looking at the IL code(compiler optimization switched on) generated for the following Interface & the class that implements the interface:

public interface IStockService
{
    [OperationContract]
    double GetPrice(string ticker);
}

public class StockService : IStockService
{
    public double GetPrice(string ticker)
    {
        return 93.45;
    }
}

IL Code :

IStockService.GetPrice:

StockService.GetPrice:
IL_0000:  ldc.r8      CD CC CC CC CC 5C 57 40 
IL_0009:  ret         

StockService..ctor:
IL_0000:  ldarg.0     
IL_0001:  call        System.Object..ctor
IL_0006:  ret         

Surprisingly I don’t see any IL code for the interface. Is this because of the way LinqPad works or the C# compiler treats the interfaces in a different manner?

Answer 1

IL is for method bodies. An interface does not contain any method bodies, thus no IL.

A method body in this case (put simply) is any executable code. Nothing in an interface is executable since it is just a contract. It’s up to the implementor of the interface to provide an implementation, which will usually contain IL.