Seeking knowledge on Early Binding, Late Binding

I have never done a course on VBA so I feel I lack understanding of certain concepts.

1. I am looking for a concise definition & explanation of Early Binding & Late Binding.
2. What is the pros & cons of each method?

In early binding, the VBA project includes a reference to the library where the methods and properties of (non-native VBA) objects are defined, so object variables may be defined and instantiated as the objects they will reference (e.g., Dim oDoc as Word.Document, Set oDoc = New Word.Document). Because objects are known at compile time, Intellisense works, and it's faster at runtime because references to properties and methods are linked to the known entry points. When referencing a library, you are, perforce, specifying a version, e.g., Word 12.

In late binding, there is no reference, and object variables are declared as Object (or, less strongly, as Variant). Intellisense doesn't work because the compiler hasn't a clue what they are. Object variables are instantiated with CreateObject() or GetObject(). At runtime, the VTable must be searched to locate the entry point for the property or method. An advantage is that it loads whatever library is most recent, so if it can't find Word 12, it will load Word 10, which affords a level of flexibility, especially if the code is being deployed to multiple computers.

Originally Posted by shg

In early binding, the VBA project includes a reference to the library where the methods and properties of (non-native VBA) objects are defined, so object variables may be defined and instantiated as the objects they will reference (e.g., Dim oDoc as Word.Document, Set oDoc = New Word.Document). Because objects are known at compile time, Intellisense works, and it's faster at runtime because references to properties and methods are linked to the known entry points. When referencing a library, you are, perforce, specifying a version, e.g., Word 12.

In late binding, there is no reference, and object variables are declared as Object (or, less strongly, as Variant). Intellisense doesn't work because the compiler hasn't a clue what they are. Object variables are instantiated with CreateObject() or GetObject(). At runtime, the VTable must be searched to locate the entry point for the property or method. An advantage is that it loads whatever library is most recent, so if it can't find Word 12, it will load Word 10, which affords a level of flexibility, especially if the code is being deployed to multiple computers.

This is the sort of explanation I was looking for! Thank you.

In short, I take it that:
Early Binding = faster & tighter/explicit
Late Binding = slower & flexible

You're welcome.

strictly speaking of course it is simply the declaration as Object or specific object type that determines the binding and not the method of instantiation. you can late bind even with a reference set-though not vice versa!

Originally Posted by JosephP

strictly speaking of course it is simply the declaration as Object or specific object type that determines the binding and not the method of instantiation. you can late bind even with a reference set-though not vice versa!

So the early/late is referring to the object declaration method? I'm afraid you lost me on the next bit...

what I mean is that

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is late binding even if you are in Excel or if you have a reference set to the excel object library, and regardless of whether you then use

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or

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to actually initialize the variable

Originally Posted by JosephP

what I mean is

Got it! Thanks!