This class is the root of all .NET
types, including value types and
reference types. Some CLR languages such as C# and VB.NET do not
require a type to inherit from Object explicitly.
If no base type is listed in a class declaration, it is assumed that
the type is to inherit from Object. Therefore, all
types derive from it implicitly and can use any of its methods.
Use the GetType( ) method to obtain a description
of your object's internal metadata as a
Type object. Use the ToString(
) method to get a String that represents
your object. By default, this is the fully qualified type name of
your object, but most classes override this method to provide
something more useful, such as a string representation of the
object's content. For example,
System.Drawing.Point.ToString( ) might return
(10, 5).
The MemberwiseClone( ) method returns a new object
of the same type that is a member-by-member duplicate. This object is
called a shallow copy because any subobjects are not copied. Instead,
the references are duplicated, meaning that both the original and
cloned type refer to the same subobjects. MemberwiseClone(
) is protected, so it can be called only from methods of
your derived object. Usually, you will implement the
ICloneable interface for your objects and call
MemberwiseClone( ) from a customized
ICloneable.Clone( ) method.
Use the Equals( ) method to test for reference
equality. Derived value-type classes override this method to provide
value equality (which returns true for identical
content, even if it is stored in different objects at different
memory addresses). Note that the equality operator (=
= in C#, = in VB.NET) does not call
Equals( ) unless the equality operator is
overloaded for the appropriate type (as it is with
String, for example).
The ReferenceEquals( ) method, while perhaps
seeming somewhat similar, compares object identity rather than object
equality. That is, while Equals( ) might return
true for two independent objects that contain the
same state, ReferenceEquals( ) checks to see if
the two references passed to it point to the same object. These two
objects are identical, which is only the case when both references
point to the same location in memory. Because the =
= operator compares references by default, but could be
changed later to compare state (or anything else),
ReferenceEquals( ) is the only safe way to test
references for identity.
The GetHashCode( ) method returns a hash code so
the object can be used as a key in a
System.Collections.Hashtable collection. By
default, GetHashCode( ) returns a unique hash code
for each object, which is sufficient for reference types but must be
overridden by all value types so that equivalent types return
identical hash codes.
public class Object {
// Public Constructors
public Object( );
// Public Static Methods
public static bool Equals(object objA, object objB);
public static bool ReferenceEquals(object objA, object objB);
// Public Instance Methods
public virtual bool Equals(object obj);
public virtual int GetHashCode( );
public Type GetType( );
public virtual string ToString( );
// Protected Instance Methods
protected override void Finalize( );
protected object MemberwiseClone( );
}
