A .NET class that represents a 128-bit signed integer. Supports all .NET Framework versions from 2 to 4, including Silverlight and Windows Phone.
I have written this class because the System.Numerics.BigInteger class is only available starting from the Framework 4, and I needed 128-bit arithmetics.
The properties and methods mimic what can be found in standard .NET classes. The class implements all standard interfaces: IComparable<T>, IComparable, IEquatable<T>, IConvertible and IFormattable. It also implements IBinarySerialize to help serialize it in a SQL Server database. It also has Parse and TryParse methods, including hexadecimal support.
I have also added a TypeConverter that eases ASP.NET or other "data binding" integration.