String formatting - the .NET way

In AX, it is possible to format strings the .NET way.
On MSDN for AX, in the strFmt article, an example is given:
s = System.String::Format("{0:##.####}", sysDouble);

See the .NET Framework Class Library String::Format Method (String, Object) article on MSDN for more information.
On MSDN, you can find more information about formatting on the following links:

• Formatting in .NET
• Standard Numeric Format Strings: overview of possible Format Specifiers
• Composite Formatting (like strFmt in AX): see "Format Item Syntax" title in the article.