Excel how to tell if workbook is already open BEFORE you try to open it.
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From: hdjim on 3 May 2010 16:57 I've been looking all over the net trying to find C# code to determine if a workbook is open before you try to open it so you can alert the user to close it before you update it. There must be a way. Please help. hd
From: Jeff Johnson on 3 May 2010 17:17 "hdjim" <hdjim69(a)yahoo.com> wrote in message news:121fe4a0-138e-497f-b6b7-32b4b3f9ef7a(a)o14g2000yqb.googlegroups.com... > I've been looking all over the net trying to find C# code to determine > if a workbook is open before you try to open it so you can alert the > user to close it before you update it. > > There must be a way. Please help. The easiest way is to try to open the file for writing and see if the operation fails (i.e., trap the exception).
From: Jeff Johnson on 3 May 2010 18:15 "Harlan Messinger" <hmessinger.removethis(a)comcast.net> wrote in message news:848tnmF251U1(a)mid.individual.net... >>> I've been looking all over the net trying to find C# code to determine >>> if a workbook is open before you try to open it so you can alert the >>> user to close it before you update it. >>> >>> There must be a way. Please help. >> >> The easiest way is to try to open the file for writing and see if the >> operation fails (i.e., trap the exception). > > When you successfully open a file for writing, doesn't that delete the > existing contents? No, depending on the mode you use to open. Think about it: how could you ever append to a file if that were the case? I guess you could also try to open for read with a ShareDenyRead lock.
From: Jeff Johnson on 4 May 2010 09:55
"Harlan Messinger" <h.usenetremoverthis(a)gavelcade.com> wrote in message news:8493ptF3mrU1(a)mid.individual.net... >>> When you successfully open a file for writing, doesn't that delete the >>> existing contents? >> >> No, depending on the mode you use to open. Think about it: how could you >> ever append to a file if that were the case? > > OK, fine, for appending. :-) The terminology is tricky--sometimes when > they say "write" they mean, as opposed to "append". I don't want to harp on it, but it isn't just appending. You can open a file for "normal" writing and alter the existing contents of a file as well as adding to the end. Most of the code samples out there for altering the contents of a file probably read the entire file into memory, alter the contents, and then write the whole thing back out, but it doesn't HAVE to be done that way. Probably the best argument against direct manipulation of a file stream is that if you're reading a file and you discover something you want to change, you have to back up the stream pointer to overwrite that particular item. Of course, you have to do this for a MemoryStream too.... For reference, the only members of the FileMode enumeration which will wipe out an existing file are Create and Truncate. |