Difference between manual locking and Synchronized methods

Question

Is there any difference between this:

internal class MyClass
{
    private readonly object _syncRoot = new Object();

    public void DoSomething() 
    {
           


        

Answer 1

check out http://blogs.msdn.com/b/bclteam/archive/2004/01/20/60719.aspx and http://www.experts-exchange.com/Programming/Languages/C_Sharp/Q_20926988.html
They discuss about lock(this) too and discourage using it since:

completely unrelated code can choose to lock on that object as well

Quoting from EE:

If you lock an object, all other threads that need to access THIS PARTICULAR OBJECT will wait, until the other object finishes. However if you mark a method as Synchronized, THIS PARTICULAR METHOD will not be executed at more than one thread. Lock secures the object, Synchronized secures the method.