Type: System.IFormatProvider An object that implements the IFormatProvider interface and is used to augment the conversion. If null is specified, format information is obtained from the current culture.
Type: System.Object The boxed equivalent of the current DBNull object, if that conversion is supported; otherwise, an exception is thrown and no value is returned.
Three conversions are supported: If the type parameter specifies Object or DBNull, the return value is the current DBNull object itself. If the type parameter specifies String, the return value is the string returned by the ToString method.