Checking for empty strings or lists

[user612345]

I am doing some validation on a form and I am checking for empty strings or empty lists.

Is this a proper way to check for an empty string in a text box?

if(Textbox.Text == String.Empty)

From my understanding this will check to see that the Text field is empty. This also prevents the use of something like the following which does the same thing.

if(Textbox.Text == "")

Which is basically doing like a magic number where I have a literal string in my code.

But how would you do this with a List or Listbox? I am trying to prevent the following where I have a hard coded 0.

if(List.Items.Count == 0)