Re: Confused about OOP programming!

Abosultely don't assume that the file is open, but you have a reference
to it and you can check it's state.. 

Ie.. IsNothing(_excelHandle) = False   then set the file

And if it is true, you can check it's open state.

-----Original Message-----
From: Discussion forum for developers using Windows Forms to build apps
and controls [mailto:[email protected]] On Behalf Of
Stuart Laughlin
Sent: Friday, March 30, 2007 11:26 AM
To: [email protected]
Subject: Re: [DOTNET-WINFORMS] Confused about OOP programming!

I attempted to send this yesterday, but it never appeared on the list...

On 3/29/07, Steve Abaffy <[email protected]> wrote:
>
> Now the problem I see here is that I am open and closing the same file
> twice.

Why is that a problem? I do the analogue with databases all the time
(i.e. open a connection, read some records, close the connection, user
selects record of interest, open a connection, read some detail
records, close the connection, etc).

> I can of course get around this problem by using a global
InputExcelObj but
> that seems to violate the do not use global variable rule.

As Stacey suggested, you could indeed use a private class-level
identifier to reference the Excel object. I think it's asking for
trouble, though. If you go this route, you still ought not to assume
that the file remains open and accessible via the class-level
identifier when the user clicks the 'process file' button.

>
> What is a better way to do this? And of course if one could use a
> ExcelObjClass where you can have methods like GetCellValue, SaveFile,
> OpenFileforRead, OpenFileForWrite etc... that would be even better.

Aren't those methods (or something very similar) already part of the
API?

http://msdn2.microsoft.com/en-us/library/aa168292(office.11).aspx


--Stuart