CODEWITHSUNDEEP
c#genericsfunc
Barry McDermid
Barry McDermid

Reputation: 339

How to get Method Name of Generic Func<T> passed into Method

I'm trying to get the method name of a function passed into an object using a .Net closure like this:

Method Signature

public IEnumerable<T> GetData<T>(Func<IEnumerable<T>> WebServiceCallback) 
where T : class    
{
    // either gets me '<LoadData>b__3'
    var a = nrdsWebServiceCallback.Method.Name;
    var b = nrdsWebServiceCallback.GetInvocationList();

    return WebServiceCallback();
}

I'm calling it like this:

SessionStateService.Labs = CacheManager.GetData(() =>  
WCFService.GetLabs(SessionStateService.var1, SessionStateService.var2));

Seeing 'b__3' instead of WCFServce.GetLabs(..) etc

Upvotes: 15

Views: 10488

Answers (2)

Avner Shahar-Kashtan
Avner Shahar-Kashtan

Reputation: 14700

What is actually passed into your function is an anonymous lambda function (() => WCFService.Etc), so what you're seeing is the actual method name - <LoadData>b__3 is the autogenerated name for the anonymous method.

What you actually want is the method called inside the method called. For that, you need to delve into expressions. Instead of Func<IEnumerable<T>>, define your parameter as Expression<Func<IEnumerable<T>>>, and call this code:

var body = nrdsWebServiceCallback.Body as MethodCallExpression;
if (body != null)
   Console.WriteLine(body.Method.DeclaringType.Name + "." + body.Method.Name);

Upvotes: 2

dcastro
dcastro

Reputation: 68680

You're looking at the name of the lambda expression (generated by the compiler), instead of the name of the method called inside the lambda.

You have to use an <Expression<Func<T>> instead of a Func<T>. Expressions can be parsed and analyzed.

Try

public IEnumerable<T> GetData<T>(Expression<Func<IEnumerable<T>>> callbackExpression) 
where T : class    
{
    var methodCall = callbackExpression.Body as MethodCallExpression;
    if(methodCall != null)
    {
        string methodName = methodCall.Method.Name;
    }

    return callbackExpression.Compile()();
}

Upvotes: 22

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