The Comment/Uncomment tool enables you to comment out a selection or delete comment delimeters with only a single keystroke. To comment out a selected code section, press Slash (/) in C# / C++, or Apostrophe (') in VB. Comment delimiters are deleted from the selection in the same way.
You can comment or uncomment selection in XML-like code as well. Use the Slash (/) or Apostrophe (') shortcut.