Difference between 'using' and scoping?

Question

What is the difference between the following two snippets of code:

using (Object o = new Object())
{
    // Do something
}

and

{
    Object o = new Object();
    // Do something
}

I have started using using a lot more but I am curious as to what the actually benefits are as compared to scoping objects.

Edit: Useful tidbits I took from this:

Jon Skeet:

Note that this does not force garbage collection in any way, shape or form. Garbage collection and prompt resource clean-up are somewhat orthogonal.

Will Eddins comment:

Unless your class implements the IDisposable interface, and has a Dispose() function, you don't use using.

Answer 1

The first snippet calls Dispose at the end of the block - you can only do it with types which implement IDisposable, and it basically calls Dispose in a finally block, so you can use it with types which need resources cleaning up, e.g.

using (TextReader reader = File.OpenText("test.txt"))
{
    // Use reader to read the file
}
// reader will be disposed, so file handle released

Note that this does not force garbage collection in any way, shape or form. Garbage collection and prompt resource clean-up are somewhat orthogonal.

Basically, you should use a using statement for pretty much anything which implements IDisposable and which your code block is going to take responsibility for (in terms of cleanup).