VB Questions

This week i got one interview with VB position...i'm a new graduate, i would like to know which questions they usually ask for new people like me, if anyone knows please help thanks.
if you got the question please answer them, thanks(because i dont know the answer)

Also I got a few questions, please answer if you know, thanks

1) What is COM stand for? And what COM do? and when do u use COM?
2) What are ADO and DAO stand for? What's difference between ADO and DAO?
3)what's MDI form mean? and when do u use it?
4)when do u use class module?

3) MDI = Multiple Document Interface

this is when you're programming 1 "Main" window and a bunch of "child" windows.

this lets you easily make a program like word, where the user opens multiple word documents at once and edits them individually.

need more explanation?

class's are nice features, for a ( obviously ) beginner like you and class is just like a TYPE declaration but ALOT more advanced and more powerful, allows to have subs/functions, types, properties

example

VB Code:

type PersonDetail
 Name as string
 Age as integer
end Type

to use that you type

dim i as PersonDetail
i.Name= "Fred"
i.Age = 42

or a class version called 'PersonDetails'

VB Code:

Dim l_Name As String
Dim l_Age As Integer
 
Public Property Get Age() As Integer
    Age = l_Age
End Property
 
Public Property Let Age(ByVal NewAge As Integer)
    If NewAge > 110 Then NewAge = 110
    If NewAge < 1 Then NewAge = 1
    
    l_Age = NewAge
End Property
 
Public Property Get Name() As String
    Name = l_Name
End Property
Public Property Let Name(ByVal NewName As String)
    l_Name = NewName
End Property

and to use this, on your form code type
dim i as PersonDetails
set i = new PersonDetails

i.Name = "Fred"
i.Age = 150


as you can see classes are much more useful, because the Age Property( Get means return value, Let means Set value ) can check for errors, as in this case the age cant be 150 and will be set to 110

I suggest you learn more standard VB before going into classes, they not newbie friendle IMO

DOA and ADO, cant remember there names but something like ActiveX Data O... umm brain gone dead.

anyway the difference, just two methods to access databases made by like MS ACCESS

as usual, theres an easy way and a harder way, DOA is the easier way and ADO is the hard way because its more powerful, this is the method MS are going towards. Theres lots of tutorials explaining about database access, check www.vbworld.com , they have some easy to understand tutorials

Component Object Model (COM)

you use these to extend the functionality of your program, and they made by compiling a class into a DLL

basically, you can load externel dll's made by other developers and import them into your project and use there fucntions. Great example of this is the MS Script Control.
You can either add the control to your form but that will require it needed when you come to package and development ( creating a setup program ). Or you can reference the MS Script dll file, by Projects>References
and call its functions by

dim i as MSScriptControl.

but doing so this way requires you to know what procedures are available to you and how to use them


Hope i made sense on my explainations

i think dao = data access object

DAO = Data Access Objects, ADO = ActiveX Data Objects

ADO objects provide you with the fastest, easiest and most productive means for accessing all kinds of data sources. The ADO model strives to expose everything that the underlying data provider can do, while still adding value by giving you shortcuts for common operations.

DAO provide a framework for using code to create and manipulate databases. DAO supplies a hierarchical set of objects that use the Microsoft Jet database engine to access data and database structure in:
Microsoft Jet (.MDB) databases
ODBC data sources, using an ODBC driver
Installable ISAM databases, such as dBASE®, Paradox™ and Microsoft FoxPro which the database engine can read directly