c#: System.Configuration.ConfigurationErrorsException (empity file)

Question

Application: Industrial PC W7 Ultimate 64 bit

Problem: We have often problem at power down ( cut off), look like this interruption corrupt file setting we use as follow: Properties.Settings.Default.

When the application start again, show up following message:

************** Exception Text **************
System.Configuration.ConfigurationErrorsException: Configuration system failed to initialize --

We use setting file for reload old value in the application grapich (Windows chart framework 3.5) Any idea Help? How to protect this writing / Reading process in system file Are there any "FileClose" in order to protect sudden power down.

the file setting is the same:

I save the configuration file in the timer. I use this code for save: (example: Properties.Settings.Default.MachineTimeWorkTot = timeMachineWork.ActualVal; Properties.Settings.Default.Save())

Thanks a lot

Adriano Repetti · Accepted Answer

In general ApplicationSettingsBase does not handle power failure scenarios.

My first and most important suggestion is to deal with this scenario using an UPS. Take the pill and accept that whatever you do you won't have a 100% reliable software solution (at best the problem may be mitigated and corruption avoided with a well-designed software implementation and/or with file system support.)

Now I assume you went out to buy an UPS and you want to make your software more reliable. The things you have to do are these:

Make a copy of your original unchanged configuration when program startups. It is proved to be correct and it can be used to restore configuration if required (changes from last run will be lost but at least you will still have something.)
If configuration fails to load then restore from backup (if present) and try to load again.

Now if you keep using ApplicationSettingsBase then you may stop here. You may want to handle ConfigurationLoading event but it's just too hacky and I'd not feel to suggest it. Alternatively you can use custom ConfigurationSection and try to save your data in a little bit more reliable way:

1) Save your settings to a new file Your App.exe.config.new.

2) Make a copy of existing settings to Your App.exe.config.bak.

3) Replace Your App.exe.config with Your App.exe.config.new.

4) Optionally delete both .bak and .new files (unless you want to keep them for recovery...somehow).

Note that point 2, 3 and partially 4 are handled by System.IO.File.Replace() function. Do not try to re-implement it unless you're sure to make it correct and add some value.

All this said...you're saving application state inside configuration files. It's not, in my opinion, the right usage. They were not designed for this purpose. You may consider to use a better and more reliable storage for your state: what about a local database? It comes with built-in reliable I/O (better than what we may expect to do by hand. Not even to mention the other advantages (possibility to query values, intrinsically shared between processes, optionally journaled, easy to update/deploy/merge and so on...)

c#: System.Configuration.ConfigurationErrorsException (empity file)

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