@"" in C#

1.
string file = "C:\\MyFolder\\MySubFolder\\MyFile.txt";
if use @
string file = @"C:\MyFolder\MySubFolder\MyFile.txt";

2.
<%= Html.TextBox("Title", Model.Title, new { size = 30, @class="myclass" } )%>
using a @ character because class is a reserved keyword in C#