Early Binding vs. Late Binding

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Before discussing about the differences, let's know what is meant by Early and Late Binding.

Early Binding

The name itself describes that compiler knows about what kind of object it is, what are all the methods and properties it contains. As soon as you declared the object, .NET Intellisense will populate its methods and properties on click of the dot button.

Common Examples:

ComboBox cboItems;
ListBox lstItems;

In the above examples, if we type the cboItem and place a dot followed by, it will automatically populate all the methods, events and properties of a combo box, because compiler already know it's an combobox.

Late Binding

The name itself describes that compiler does not know what kind of object it is, what are all the methods and properties it contains. You have to declare it as an object, later you need get the type of the object, methods that are stored in it. Everything will be known at the run time.

Common Examples:

Object objItems;
objItems = CreateObject("DLL or Assembly name");

Here during the compile time, type of objItems is not determined. We are creating an object of a dll and assigning it to the objItems, so everything is determined at the run time.

Early Binding vs. Late Binding

Now coming into the picture…

Application will run faster in Early binding, since no boxing or unboxing are done here.
Easier to write the code in Early binding, since the intellisense will be automatically populated
Minimal Errors in Early binding, since the syntax is checked during the compile time itself.
Late binding would support in all kind of versions, since everything is decided at the run time.
Minimal Impact of code in future enhancements, if Late Binding is used.
Performance will be code in early binding.

Both have merits and demerits, it's the developer decision to choose the appropriate binding based on the scenario.