We are developing an application to manage customer records for a
phone company. We have come to a disagreement in the project about
what exactly the difference is between SDI & MDI. I tend to follow the
standard definition given in all the Microsoft documentation (an MDI
program is one that allows multiple views of an object through child
windows, all enclosed in one parent window & the parent window is the
only one with a menu bar. SDI allows one single view of an object).
An associate of mine disagrees with this definition. He says that with
an SDI program you have only one main window, but you can have many
instances of main windows, or in other words you have the ability to
retrieve multiple occurances of an object (in our case, different
customers). Each of these main windows would have a meu bar that would
allow action to be taken (saving,editing) on the object in the
associated window (in this case, our customer information). I'm not
familiar with the Windows architecture but I'm fairly sure that this
is not an SDI application....I am thinking this is more of a
multithreading thing. Can anyone clarify?
I guess another way to ask this question would be to say that we are
developing an application that requires us to be able to retrieve
multiple, different customers and have them open in different windows
at the same time, each with their own menu bars. Would this be an SDI
or MDI application and would it have to be multithreaded?

Any help greatly appreciated!

Brian

Hi Brian,

What your describing is definitely a MDI application.  SDI applications have one
application window.  It is possible to have more than one view however, only one
can be viewed at any given time.  An MDI application also only has one
application window but can have multiple views open at the same time.  Each MDI
child window has it's own menu which replaces the application's menu when the
child has the focus and may or may not have it's own toolbar.  Toolbars in MDI
child windows are not directly supported by MFC but can be managed manually.
Although you can implement multithreading in either of these types of
applications it isn't a requirement.

My personal recommendation is: If only one customer record will be viewed at any
one time, it may be adequate to go SDI however, I would probably go MDI because
it sounds more suited to the task.

HTH
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Frank Hickman
NobleSoft, Inc.

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