Locking by string. Is this safe/sane?

Question

I need to lock a section of code by string. Of course the following code is hideously unsafe:

lock(\"http://someurl\")
{
    //bla
}

So I\'

Answer 1

Now I have the same issue. I decided to use simple solution: to avoid deadlocks create a new string with fixed unique prefix and use it as a lock object:

lock(string.Intern("uniqueprefix" + url))
{
//
}