Escaping Curly Bracket in String.Format()

If you need to print a curly bracket in string, when using string format, just put it twice in a row.

string.Format("{{ hello world }}")//{ hello world };
string.Format("{{0}}", 45);//{0}
string.Format("{{{0}}}", 45);//{45}
string.Format("{0:N}", 45);//45.00
string.Format("{{{0:N}}}", 45);//{N}

The last one is not `{45.00}`, because the parser when reading `}}}` first prints the escaped `}`, and only then closes the formatting section. And as `N}` number format does not mean anything to it, it just prints it out.