Object References
When we work with an object we are using a reference to that object. On the other hand, when we are working with simple data types such as Integer, we are working with the actual value rather than a reference.
When we create a new object using the New keyword, we store a reference to that object in a variable. For instance:
Draw MyDraw = new Draw;
This code creates a new instance of Draw. We gain access to this new object via the MyDraw variable. This variable holds a reference to the object.
Now we have a second variable, which also has a reference to that same object. We can use either variable interchangeably, since they both reference the exact same object. The thing we need to remember is that the variable we have is not the object itself but, rather, is just a reference or pointer to the object itself.
Early binding means that our code directly interacts with the object, by directly calling its methods. Since the compiler knows the object's data type ahead of time, it can directly compile code to invoke the methods on the object. Early binding also allows the IDE to use IntelliSense to aid our development efforts; it allows the compiler to ensure that we are referencing methods that do exist and that we are providing the proper parameter values.
Late binding means that our code interacts with an object dynamically at run-time. This provides a great deal of flexibility since our code literally doesn't care what type of object it is interacting with as long as the object supports the methods we want to call. Because the type of the object isn't known by the IDE or compiler, neither IntelliSense nor compile-time syntax checking is possible but we get unprecedented flexibility in exchange.
If we enable strict type checking by using Option Strict On at the top of our code modules, then the IDE and compiler will enforce early binding behavior. By default, Option Strict is turned off and so we have easy access to the use of late binding within our code.
By Milan Saxena
Category:
C#,
OOPS
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