C# 0 The Complete Reference

o

 in 

ob1

 and 

o

 in 

ob2

 both refer to the same 

X

 object. Changing one affects both. 

Of course, the 

int

 field 

b

 in each is still separate because the value types are not accessed via 

references.

IFormatProvider and IFormattable

The

IFormatProvider

 interface defines one method called 

GetFormat( )

, which returns an 

object that controls the formatting of data into a human-readable string. The general form of 

GetFormat( )

 is shown here:

object GetFormat(Type 

fmt

)

Here, 

fmt

 specifies the format object to obtain.

The

IFormattable

 interface supports the formatting of human-readable output. 

IFormattable

 defines this method:

string ToString(string 

fmt

, IFormatProvider 

fmtpvdr

)

Here, 

fmt

 specifies formatting instructions and 

fmtpvdr

specifies the format provider.