Extract method name from expression tree?

.net, c#, expression-trees, linq, reflection

Solution

You're half way there. Look at the code below

public static void Main(string[] args)
{
    var program = new Program();
    var methodInfo = GetMethod<Program, EventArgs>(()=> program.Method);
    Console.WriteLine(methodInfo.Name);
}

And use the following code to get the method name.

static MethodInfo GetMethod<TTarget, TEventArgs>(Expression<Func<EventHandler<TEventArgs>>> method) where TEventArgs:EventArgs
{
    var convert = method.Body as UnaryExpression;
    var methodCall = (convert.Operand as MethodCallExpression);
    if (methodCall != null && methodCall.Arguments.Count>2 && methodCall.Arguments[2] is ConstantExpression)
    {
        var methodInfo = (methodCall.Arguments[2]as ConstantExpression).Value as MethodInfo;
        return methodInfo;
    }
    return null;
}

I hope this answers your question.

Problem

I am trying to implement the following pattern function: ``` MethodInfo GetMethod( Expression<Func<TTarget, EventHandler<TEventArgs>>> method) ``` I can provide an instance of TTarget if required The desired usage is: ``` public static void Main(string[] args) { var methodInfo = GetMethod<Program, EventArgs>(t => t.Method); Console.WriteLine("Hello, world!"); } private void Method(object sender, EventArgs e) { } ``` Here's what I've tried so far: ``` private static MethodInfo GetMethod(TTarget target, Expression<Func<TTarget, EventHandler<TEventArgs>>> method) { var lambda = method as LambdaExpression; var body = lambda.Body as UnaryExpression; var call = body.Operand as MethodCallExpression; var mInfo = call.Method as MethodInfo; Console.WriteLine(mInfo); throw new NotImplementedException(); } ``` It prints out: `System.Delegate CreateDelegate(System.Type, System.Object, System.Reflection.Met hodInfo)`

Original source