检查基础 class 是否使用 Roslyn 实现了某个接口

Question

UPDATE:

As it turns out, I am an idiot. Instead of deriving from BaseClass , I made a typo and derived from another class with a very similar name -- let's say BassClass .

Many thanks to @canton7 for patiently guiding me through the debugging process.

---

Here is some sample code:

using System;

public interface SomeInterface {}

public class SomeAttribute : Attribute
{
}

[SomeAttribute]
public class BaseClass : SomeInterface
{
}

[SomeAttribute]
public class DerivedClass : BaseClass
{
}

Through inspecting the syntax node that represents DerivedClass , I want to be able to know that DerivedClass implements SomeInterface , by virtue of its being derived from BaseClass .

Here is what I have so far:

SemanticModel semanticModel = context.Compilation.GetSemanticModel(candidateSyntax.SyntaxTree);
ISymbol candidateSymbol = semanticModel.GetDeclaredSymbol(candidateSyntax);

if (!ImplementsSomeInterface(candidateSymbol))
{
    // Do something
}

bool ImplementsSomeInterface(ISymbol symbol)
{
    return symbol is ITypeSymbol typeSymbol && typeSymbol.AllInterfaces.Any(i => i.Name == "SomeInterface");
}

ImplementsSomeInterface returns true for BaseClass but false for DerivedClass . typeSymbol.AllInterfaces.Count() is 1 for BaseClass and 0 for DerivedClass .

How should I implement the ImplementsSomeInterface method, so that it returns true also for DerivedClass ?

Answer 1

You can achieve it easily, using reflections:

var temp = typeof (B).GetInterfaces ().Contains (typeof (Isome));

If that's not the case, perhaps try write all of them to console, to check does it fetches those interfaces right.