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.NET Forum / .NET Framework / Compact Framework / November 2007Delete from file
I know that it generally isn't possible to delete a part of a file, but I'll pop this question anyway in case there is a good idea out there: I have a program that runs on a PDA with e.g. 32MB storage. The program generate a file and if the file exceed 16MB I do not have the possibility to delete a single character from the file, because I normally will have to create a new file without the character and after that delete the original file ---- or what???? Thanks Ole I don't understand what you are trying to achieve. Are you saying, when the file equals a certain size, you want to delete it?  SignatureSimon Hart Visual Developer - Device Application Development MVP http://simonrhart.blogspot.com > I know that it generally isn't possible to delete a part of a file, but I'll > pop this question anyway in case there is a good idea out there: [quoted text clipped - 7 lines] > Thanks > Ole Sounds like he wants to remove a section of a file that is half the size of the available storage. Since you can't just cut out some bytes from the middle, the only practical way to do it is to create a new file and copy just the parts of the old file that you want into the new file. However, if the old file is half the size of the storage, that's a problem. There's no fix that I can think of other than to stop growing the other file sooner... Paul T. >I don't understand what you are trying to achieve. Are you saying, when the > file equals a certain size, you want to delete it? [quoted text clipped - 13 lines] >> Thanks >> Ole The only thing I could think of is opening the file multiple times with share access and doing some form of data "shift" using two file pointers - essentially copying file data within the target file itself. It could be slow and terribly thrashy if, for example, you deleted a single byte at the start of a 16MB file. You'd end up copying the entire 16MB one byte at a time to shift it. On the plus side, at least it would work. SignatureChris Tacke, eMVP Join the Embedded Developer Community http://community.opennetcf.com > Sounds like he wants to remove a section of a file that is half the size > of the available storage. Since you can't just cut out some bytes from [quoted text clipped - 24 lines] >>> Thanks >>> Ole Sounds like a very useful idea and exactly what I was looking for - will try it out. Thanks Ole > The only thing I could think of is opening the file multiple times with > share access and doing some form of data "shift" using two file pointers - [quoted text clipped - 34 lines] >>>> Thanks >>>> Ole I wonder what happens to the "Tale" of the file and how to tell the OS that the file has decreased in size.? If I have a file of e.g. 10 KB in size and I want to delete 1 KB from the middle of it, then I according to the below, should "shift" the upper part of the file downwards until the the last byte which is the EOF, but what happens to the last 10KB? Are there any code snippets available? Thanks, Ole > The only thing I could think of is opening the file multiple times with > share access and doing some form of data "shift" using two file pointers - [quoted text clipped - 8 lines] > Join the Embedded Developer Community > http://community.opennetcf.com Simply call SetLength on the FileStream to the new length, Flush and Close. SignatureChris Tacke, eMVP Join the Embedded Developer Community http://community.opennetcf.com >I wonder what happens to the "Tale" of the file and how to tell the OS that >the file has decreased in size.? If I have a file of e.g. 10 KB in size and [quoted text clipped - 18 lines] >> Join the Embedded Developer Community >> http://community.opennetcf.com Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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