Can you use reflection to find the name of the currently executing method?

Question

Like the title says: Can reflection give you the name of the currently executing method.

I'm inclined to guess not, because of the Heisenberg problem. How do you call a method that will tell you the current method without changing what the current method is? But I'm hoping someone can prove me wrong there.

Update:

• Part 2: Could this be used to look inside code for a property as well?
• Part 3: What would the performance be like?

Final Result
I learned about MethodBase.GetCurrentMethod(). I also learned that not only can I create a stack trace, I can create only the exact frame I need if I want.

To use this inside a property, just take a .Substring(4) to remove the 'set_' or 'get_'.

Answer 1

As of .NET 4.5 you can also use [CallerMemberName]

Example: a property setter (to answer part 2):

    protected void SetProperty<T>(T value, [CallerMemberName] string property = null)
    {
        this.propertyValues[property] = value;
        OnPropertyChanged(property);
    }

    public string SomeProperty
    {
        set { SetProperty(value); }
    }

The compiler will supply matching string literals at callsites, so there is basically no performance overhead.

Answer 2

System.Reflection.MethodBase.GetCurrentMethod().Name;

http://msdn.microsoft.com/en-us/library/system.reflection.methodbase.getcurrentmethod.aspx

Answer 3

The snippet provided by Lex was a little long, so I'm pointing out the important part since no one else used the exact same technique:

string MethodName = new StackFrame(0).GetMethod().Name;

This should return identical results to the MethodBase.GetCurrentMethod().Name technique, but it's still worth pointing out because I could implement this once in its own method using index 1 for the previous method and call it from a number of different properties. Also, it only returns one frame rather then the entire stack trace:

private string GetPropertyName()
{  //.SubString(4) strips the property prefix (get|set) from the name
    return new StackFrame(1).GetMethod().Name.Substring(4);
}

It's a one-liner, too ;)

Answer 4

Try this inside the Main method in an empty console program:

MethodBase method = MethodBase.GetCurrentMethod();
Console.WriteLine(method.Name);

Console Output:
Main

Answer 5

Yes definitely.

If you want an object to manipulate I actually use a function like this:

public static T CreateWrapper<T>(Exception innerException, params object[] parameterValues) where T : Exception, new()
{
    if (parameterValues == null)
    {
        parameterValues = new object[0];
    }

    Exception exception   = null;
    StringBuilder builder = new StringBuilder();
    MethodBase method     = new StackFrame(2).GetMethod();
    ParameterInfo[] parameters = method.GetParameters();
    builder.AppendFormat(CultureInfo.InvariantCulture, ExceptionFormat, new object[] { method.DeclaringType.Name, method.Name });
    if ((parameters.Length > 0) || (parameterValues.Length > 0))
    {
        builder.Append(GetParameterList(parameters, parameterValues));
    }

    exception = (Exception)Activator.CreateInstance(typeof(T), new object[] { builder.ToString(), innerException });
    return (T)exception;
}

This line:

MethodBase method     = new StackFrame(2).GetMethod();

Walks up the stack frame to find the calling method then we use reflection to obtain parameter information values passed to it for a generic error reporting function. To get the current method simply use current stack frame (1) instead.

As others have said for the current methods name you can also use:

MethodBase.GetCurrentMethod()

I prefer walking the stack because if look internally at that method it simply creates a StackCrawlMark anyway. Addressing the Stack directly seems clearer to me

Post 4.5 you can now use the [CallerMemberNameAttribute] as part of the method parameters to get a string of the method name - this may help in some scenarios (but really in say the example above)

public void Foo ([CallerMemberName] string methodName = null)

This seemed to be mainly a solution for INotifyPropertyChanged support where previously you had strings littered all through your event code.

Answer 6

Comparing ways to get the method name -- using an arbitrary timing construct in LinqPad:

CODE

void Main()
{
    // from http://blogs.msdn.com/b/webdevelopertips/archive/2009/06/23/tip-83-did-you-know-you-can-get-the-name-of-the-calling-method-from-the-stack-using-reflection.aspx
    // and https://stackoverflow.com/questions/2652460/c-sharp-how-to-get-the-name-of-the-current-method-from-code

    var fn = new methods();

    fn.reflection().Dump("reflection");
    fn.stacktrace().Dump("stacktrace");
    fn.inlineconstant().Dump("inlineconstant");
    fn.constant().Dump("constant");
    fn.expr().Dump("expr");
    fn.exprmember().Dump("exprmember");
    fn.callermember().Dump("callermember");

    new Perf {
        { "reflection", n => fn.reflection() },
        { "stacktrace", n => fn.stacktrace() },
        { "inlineconstant", n => fn.inlineconstant() },
        { "constant", n => fn.constant() },
        { "expr", n => fn.expr() },
        { "exprmember", n => fn.exprmember() },
        { "callermember", n => fn.callermember() },
    }.Vs("Method name retrieval");
}

// Define other methods and classes here
class methods {
    public string reflection() {
        return System.Reflection.MethodBase.GetCurrentMethod().Name;
    }
    public string stacktrace() {
        return new StackTrace().GetFrame(0).GetMethod().Name;
    }
    public string inlineconstant() {
        return "inlineconstant";
    }
    const string CONSTANT_NAME = "constant";
    public string constant() {
        return CONSTANT_NAME;
    }
    public string expr() {
        Expression<Func<methods, string>> ex = e => e.expr();
        return ex.ToString();
    }
    public string exprmember() {
        return expressionName<methods,string>(e => e.exprmember);
    }
    protected string expressionName<T,P>(Expression<Func<T,Func<P>>> action) {
        // https://stackoverflow.com/a/9015598/1037948
        return ((((action.Body as UnaryExpression).Operand as MethodCallExpression).Object as ConstantExpression).Value as MethodInfo).Name;
    }
    public string callermember([CallerMemberName]string name = null) {
        return name;
    }
}

RESULTS

reflection reflection

stacktrace stacktrace

inlineconstant inlineconstant

constant constant

expr e => e.expr()

exprmember exprmember

callermember Main

Method name retrieval: (reflection) vs (stacktrace) vs (inlineconstant) vs (constant) vs (expr) vs (exprmember) vs (callermember) 

 154673 ticks elapsed ( 15.4673 ms) - reflection
2588601 ticks elapsed (258.8601 ms) - stacktrace
   1985 ticks elapsed (  0.1985 ms) - inlineconstant
   1385 ticks elapsed (  0.1385 ms) - constant
1366706 ticks elapsed (136.6706 ms) - expr
 775160 ticks elapsed ( 77.516  ms) - exprmember
   2073 ticks elapsed (  0.2073 ms) - callermember


>> winner: constant

---

Note that the expr and callermember methods aren't quite "right". And there you see a repetition of a related comment that reflection is ~15x faster than stacktrace.

Answer 7

EDIT: MethodBase is probably a better way to just get the method you're in (as opposed to the whole calling stack). I'd still be concerned about inlining however.

You can use a StackTrace within the method:

StackTrace st = new StackTrace(true);

And the look at the frames:

// The first frame will be the method you want (However, see caution below)
st.GetFrames();

However, be aware that if the method is inlined, you will not be inside the method you think you are. You can use an attribute to prevent inlining:

[MethodImpl(MethodImplOptions.NoInlining)]

Answer 8

The simple way to deal is:

System.Reflection.MethodBase.GetCurrentMethod().DeclaringType.FullName + "." + System.Reflection.MethodBase.GetCurrentMethod().Name;

If the System.Reflection is included in the using block:

MethodBase.GetCurrentMethod().DeclaringType.FullName + "." + MethodBase.GetCurrentMethod().Name;

Answer 9

How about this this:

StackFrame frame = new StackFrame(1);
frame.GetMethod().Name; //Gets the current method name

MethodBase method = frame.GetMethod();
method.DeclaringType.Name //Gets the current class name

Answer 10

I think you should be able to get that from creating a StackTrace. Or, as @edg and @Lars Mæhlum mention, MethodBase.GetCurrentMethod()

Answer 11

If you need just the string name of the method, you can use Expressions. See http://joelabrahamsson.com/entry/getting-property-and-method-names-using-static-reflection-in-c-sharp

Answer 12

Try this...

    /// <summary>
    /// Return the full name of method
    /// </summary>
    /// <param name="obj">Class that calls this method (use Report(this))</param>
    /// <returns></returns>
    public string Report(object obj)
    {
        var reflectedType = new StackTrace().GetFrame(1).GetMethod().ReflectedType;
        if (reflectedType == null) return null;

        var i = reflectedType.FullName;
        var ii = new StackTrace().GetFrame(1).GetMethod().Name;

        return string.Concat(i, ".", ii);
    }

Answer 13

I just did this with a simple static class:

using System.Runtime.CompilerServices;
.
.
.
    public static class MyMethodName
        {
            public static string Show([CallerMemberName] string name = "")
            {
                return name;
            }
        }

then in your code:

private void button1_Click(object sender, EventArgs e)
        {
            textBox1.Text = MyMethodName.Show();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            textBox1.Text = MyMethodName.Show();
        }