So I recently updated my application to support a new feature. In the past if the configuration file was deleted by the user it wasn't a big deal. This new feature requires it to exist, and one of the requirements is that, the file exists in the application's installation directory.
I have notice when the file is deleted ( depending on variables I have not figured out ) I get a .NET notification that the configuration file is missing or corrupt. Currently my program then crashes ( I still have to figure out how to duplicate this behavior ) which is the reason for this question.
I am familar with ConfigurationManager. I am having trouble writting the file once the default values are loaded. Forcing a Save for some reason does not seem to recreate the file, at least not in the installation directory, which is a requirement.
I am looking for guidence on how to handle this corner case in an elegant manner. I would post code, honestly its just all failed attempts, which while my attempts do generate a file the contents are not the settings I am looking for.
I am willing to post anything that might be able to help.
Stop using the built-in config support and just use write/read to a file called something.exe.config using the standard XML classes and if that gets deleted, just re-create it from values hard-coded in the executable.
The config file support is supposed to make things easier, if you need to do stuff where it makes things difficult, don't use it.
Something like
var wcfm = new WebConfigurationFileMap();
Configuration newConfig = WebConfigurationManager.OpenMappedWebConfiguration(wcfm, "/");
newConfig.Save();
doesn't work?
You dont. Under normal conditions the program can not write into it's install directory - this is a standard windows security issue and the reason why app application data should reside ni external (from the exe's point) driectories.
If an admin deletes the config file, crash, ask for reinstall. There is nothing you can RELIABLY do, as you can not assume you can write into the folder at runtime. A message followed by an event log entry is the best approach here. Users are not supposed to delete parts of the application.
Related
I am working on an application that keeps track and uses files stored on the file system. Users are allowed to open, create, delete and move files in the file system. Meanwhile my application is not constantly running so I can't keep track of all changes real-time. Afterwards my application has to find out what file is whom (i.c. as identified in my application).
The most preferred solution for the users is that the application solves every change itself. Each user-interaction is less preferred.
One of my ideas was to use an attribute of a file and assign a key-value to it so when it has been identified once, it can always been recognized afterwards. But I don't know if there is such an attribute. This article didn't give much hope: There is in Windows file systems a pre computed hash for each file?.
Does somebody know if there is such an attribute I can use? And how can I used it in C#?
Is there anyone who is running up against this problem? And how did you solve it?
I'd like to hear good suggestions.
regards, Jaap
If your files don't leave NTFS, this is easily achievable by alternative data streams, where you can store your data along with files. This is more-or-less good article about ADS: http://www.flexhex.com/docs/articles/alternate-streams.phtml
There is another suitable method - it's very efficient, but also very complicated to use, it requires quite good knowledge about NTFS internals - USN Change Journal; see http://msdn.microsoft.com/en-us/library/windows/desktop/aa363798.aspx. With USN Change Journal, you can "get" very efficiently all files that were changed (even all change events) within specified time period.
Nevertheless, if your files leave NTFS realm, e.g. if it's copied to FAT32, contents of ADS is lost.
Relying on a File attribute is "dangerous" in that some user could alter the attribute while your program isn't running. This could lead you to believe that a certain file is (or isn't) tracked by the program while it really isn't.
I would suggest to keep track of the files in a database, XML, or some other file. When your application starts you read the file/db and check for new/deleted/editted files.
You could store a Hash of the files to find out if a file has been moved/editted. Keeping track of files that are moved AND editted is going to be pretty difficult. (I have no clue how you could achieve it)
PS: Have you considered making your application a Windows service? Having the file-management running in the background no matter if the GUI part of your application is running or not?
I have an app that has search functionality. The search algorithm is compiled to a separate dll. In the C# code for the search algorithm, I am using strings held in a settings file to point to the directory where the search index resides. But once the search code is compiled, the settings file is somehow incorporated in the dll. I want to have multiple versions of this code running on my server with each pointing to a different location for the index. And I want the operator to change a file to have each version point to something else as they find necessary. Both config files and settings files end up getting incorporated in the dll. How do I then accomplish this? What is the right industry standard way of doing this?
It's strange that the settings file is compiled... are you sure about that? Setting, config and resx files should be copied to the output directory, it's even a property you can modify on solution explorer. Then you should get it's values by doing
System.Configuration.ConfigurationManager.AppSettings.Get("YourKey")
But I think this won't know about user changes until app is restarted. If you want settings to be dynamic you should either store them on a database, or on a file that you open, read and close every time you need it.
Hope this helped!
So for example, when I load word, if I go to save a file, it will default to the same directory that I selected last time...Also, it keeps track of the last 10 (or whatever) .doc files you opened
how does it do this? Right now for a program I am writing (in C#), I just save a text document which holds these kinds of settings...is this bad practice??
If not, where should I put this text doc. Right now I am just using:
Path.GetDirectoryName(Application.ExecutablePath);
as the directory where this file is held...its fine before I publish the program, because it just uses one of the folders in the solution directory...
But after I publish it, the directory is really weird:
C:\users\me\AppData\Local\Apps\2.0\J6AAL16C.2QW.....
and it goes on....So is this like a directory created for this program when I install it?? is this where it SHOULD be getting saved?
Thanks!!
The Application Settings feature of .NET makes this pretty simple, really. In particular I wouldn't use the registry if I were you - it makes it harder for users to copy settings from machine to machine, etc.
It does get a bit weird if you try writing your own settings providers though - I've tried to understand the overall design a couple of times, and always got lost. For simple applications though, it's easy.
I am by no means a programmer but currently am wondering if an application creates a temp file that windows names. For example the file it creates is tmp001, is there a way i can take that name tmp001 and ask windows to give me the next temp file it would create before it creates it.
Thanks,
Mike
There is no direct means to get to know the next temporary filename to be created.
For example, programmers use the System.IO.Path.GetTempFileName method, but one can add application-specific prefixes or suffixes in order to make it easier for the application to find its newly created files.
One can even choose to save this temporary file elsewhere than the system Temp folder.
You would need to define a "temp file" much more explicitly in order to answer this question with a "Yes". The problem is that a "temp file" is just something not meant to be kept. It could exist anywhere on the system and be created by a user, application, or service. This would make it nearly (or actually) impossible to answer your question with a "Yes".
If you constrain the definition of a temp file to just the files in the official temp folder (or a subfolder), you still have a problem if you're trying to catch names not generated by windows. Any app could produce a particularly named temp file in that folder, without Windows caring.
If you further constrain the definition to be only those files named by Windows, you might be able to get somewhere. But, does that really meet your needs?
After all of that, maybe it would be better to describe the problem you're trying to solve. There may be a much better (workable) solution that would address the issue.
Typically applications use the Win32 API GetTempFileName to get the temporary directory.
The process of how the temp file is generated is described there.
I'm not sure why you want this info, but perhaps you could for example register for directory changes via a Win32 API like ReadDirectoryChangesW or by using a mini filter driver.
This kind of code just cannot work reliably on a multi-tasking operating system. Another thread in another process might pre-empt yours and claim the file name you are hoping to create.
This is otherwise easy enough to work around, just name your own files instead of relying on Windows doing it for you. Do so in the AppData folder so you'll minimize the risk of another process messing it up.
I can't see anything on here but I do remember being told that If you want an application to update a config file then it needs to be under ...
**C:\Users\Ibrar Mumtaz\AppData**
Well somewhere there, the reason being is that the user should have permisions to update a config file here and not under the applications install folder. This is the impression that I am under and I'm fairly certain that this is definately the case. As I think I read that on here = p
My question is, is there anybody on here that can shine some light on this as this is the last feature I want to implement before I give my application out to test.
1) First thing is, an installer is needed to set up the folder and then drop my apps config file into it. I already am using the visial studio installer so I have my app packaged up but this point is throwing me off? How do I do this then? I just need someone to show how to do this and I should be O.K reconfiguring my app to look for the new home of the config file.
2) I should be able to work out how to find the folder and locate the config file found within it. As once I know the installer is chucking the config file out into the right folder where the user has permissions then it should be straight forward from there.
Thanks for reading.
UPDATE:
It was pretty straight foward, as the VS Installer has an option to add a special folder so all that was left was to access the folder programmatically and read and write to the config file. ONE PROBLEM? The ConfigurationManager class which I have used to create my config file for my application expects my config file to be local to the application and not miles away in a completey different part of the local FileSystem? Errr help here Plz?
Ibrar
If you are using the VS Settings file to create application setting keys, and have values that the user might want to change in runtime, and save his preferences, just set the scope of those settings to "User" instead of "Application".
That way you will have a setter method for them, and you can edit the Settings.Default instance, and when you are done call the Save() method to persist them to disk.
The file will be saved in the user's "AppData" folder, wherever it is, under some cryptic folder. But you needn't worry about it's location most of the time, since it will be read automatically on the next execute, and persisted to the same location on subsequent runs.
Afaik the installer can be extended with classes that do things.
On INSTALL-action to do could be to
var path = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
"My app name");
if (!Directory.Exists(path)) Directory.CreateDirectory(path);
And vice-versa on uninstall.
App.config files are related to where the physical assembly is located I think.
Actually, if your app is running on the user's machine- it will have whatever permissions that user has. So most likely, you can expect to be able to write anywhere on the file system.
However it is possible the user would be running under a restricted acct, and thus not have the permissions. So you could just use the registry to store where your config file is (install folder), then when you try to update it, if it fails for permissions, ask the user to grant it.
Or you could use the Windows standard folders, as you were getting at, because doing so also separates out user data from application data.
Use the Environment.GetFolderPath () method to get the 'special folder' paths in your app.
http://www.programmersheaven.com/2/Les_CSharp_15_p2
http://msdn.microsoft.com/en-us/library/14tx8hby.aspx
If you are talking about application settings found on project Properties -> Settings tab, then there're two different types of settings: user-level and application-level.
If you need to change any settings in run-time, these would be user-level settings (http://msdn.microsoft.com/en-us/library/cftf714c.aspx) and all changes would be buried somewhere in the private folder in your user profile.
If you want to update application-level settings, your best shot would be to do that during software installation. In this case you don't need to look for the configuration file (YourApp.exe.config) anywhere but in the application folder. More likely you would need to create some sort of post-install event handler in your setup package and run some script or another application which would update data in YourApp.exe.config. Everything in the setup package will be executed with elevated priviledges and thus that configuration file would be writeable. BTW, this scenario applies to 2000 and XP, if the user is using limited user account type priviledges.
Because I did not technically find the answer I was looking for, after 6 months I have come back to my application and have managed to produce a solution that does not break my current architecture.
If you are implementing an application to make use of some of the features on offer by the ConfigurationManager then it offers a static method called:
ConfigurationManager.OpenMappedExeConfiguration(); // takes two arguements.
It can be used like this:
ExeConfigurationFileMap fileMap = new ExeConfigurationFileMap();
fileMap.ExeConfigFilename = returnUsersAppDataFolderPath();
Configuration config = ConfigurationManager.OpenMappedExeConfiguration(fileMap, ConfigurationUserLevel.None);
e.g
fileMap.ExeConfigFileName = #"some file path external to your applications install folder."
remember to use '#' symbol in front to allow the compiler to literally treat the string on as is basis.
If the config file can be conveniently locally located then just use the:
ConfigurationManager.OpenExeConfiguration(string exePath)
Above is what you would typically use but for me i needed my config file to located under the users AppData folder so the first option is what I needed. And it does indeed work.
I hope this helps others as it does for me as I want to deploy my application to Win7 and vista environments therefore this question needed asking if I was to stick to using the ConfigurationManager it's a shame the method of choice in the end never really stood out in the first place = ).
If you want to read from your config file then leave a comment and I will show you how I managed to do that also.