How can I find the method that called the current method?

You can use Caller Information and optional parameters:

public static string WhoseThere([CallerMemberName] string memberName = "")
{
       return memberName;
}

This test illustrates this:

[Test]
public void Should_get_name_of_calling_method()
{
    var methodName = CachingHelpers.WhoseThere();
    Assert.That(methodName, Is.EqualTo("Should_get_name_of_calling_method"));
}

While the StackTrace works quite fast above and would not be a performance issue in most cases the Caller Information is much faster still. In a sample of 1000 iterations, I clocked it as 40 times faster.

A quick recap of the 2 approaches with speed comparison being the important part.

http://geekswithblogs.net/BlackRabbitCoder/archive/2013/07/25/c.net-little-wonders-getting-caller-information.aspx

Determining the caller at compile-time

static void Log(object message, 
[CallerMemberName] string memberName = "",
[CallerFilePath] string fileName = "",
[CallerLineNumber] int lineNumber = 0)
{
    // we'll just use a simple Console write for now    
    Console.WriteLine("{0}({1}):{2} - {3}", fileName, lineNumber, memberName, message);
}

Determining the caller using the stack

static void Log(object message)
{
    // frame 1, true for source info
    StackFrame frame = new StackFrame(1, true);
    var method = frame.GetMethod();
    var fileName = frame.GetFileName();
    var lineNumber = frame.GetFileLineNumber();

    // we'll just use a simple Console write for now    
    Console.WriteLine("{0}({1}):{2} - {3}", fileName, lineNumber, method.Name, message);
}

Comparison of the 2 approaches

Time for 1,000,000 iterations with Attributes: 196 ms
Time for 1,000,000 iterations with StackTrace: 5096 ms

So you see, using the attributes is much, much faster! Nearly 25x faster in fact.

In C# 5, you can get that information using caller info:

//using System.Runtime.CompilerServices;
public void SendError(string Message, [CallerMemberName] string callerName = "") 
{ 
    Console.WriteLine(callerName + "called me."); 
} 

You can also get the [CallerFilePath] and [CallerLineNumber].

Try this:

using System.Diagnostics;
// Get call stack
StackTrace stackTrace = new StackTrace(); 
// Get calling method name
Console.WriteLine(stackTrace.GetFrame(1).GetMethod().Name);

one-liner:

(new System.Diagnostics.StackTrace()).GetFrame(1).GetMethod().Name

It is from Get Calling Method using Reflection [C#].