Early and Late Binding

Binding refers the object type definition. You are using Early Binding if the object type is specified when declaring your object. Eg if you say Dim myObject as ADODB.Recordset that is early binding(VB example).

If on the other hand you declare your object as a generic type you are late binding. Eg if you Dim myObject as Object (VB example).

One should note that binding is determined at object declaration and not at object instantiation. Therefore it does not matter if you later go on to Set myObject = New ADODB.Recordset or Set myObject = CreateObject(”ADODB.Recordset”).

Early binding allows developers to interact with the object’s properties and methods during coding. You can enjoy the benefits of intellisense. Also, early binding permits the compiler to check your code. Errors are caught at compile time. Early binding also results in faster code. It’s disadvantage is that you cannot create a generic object which may be bound to different types of objects.

Late binding on the other hand permits defining generic objects which may be bound to different objects. Eg you could declare myControl as Control without knowing which control you will encounter. You could then query the Controls collection and determine which control you are working on using the TypeOf method and branch to the section of your code that provides for that type. This is the only benefit of late binding. It’s disadvantages are that it is error prone and you will not enjoy much intellisense whilst coding.