Could someone tell me the advantages to using the ConfigurationManager class which load's a config file for manipulation VS an XML file with a class you build to read it yourself?
Recently, I built a class which inherits from ConfigurationSection in order to manipulate a custom section within app.config. This was quite a bit of work compared to just opening and reading an XML file.
Some people chose the first approach, others chose the second.
What's good practice?
This is an old question, but what the hell... so yes, there is quite some code overhead in writing configuration sections and elements, but what you get as compared to using your own class with an XML serializer include:
Type conversions and validations: if one of your configuration settings is, say, a "Type" (maybe you store in your configuration what kind of implementation you need to create for some provider), then the ConfigurationManager will not only convert whatever was written in the .config file to a System.Type, but you can also add validation attribtues on your ConfigurationElement's property, like "SubclassTypeValidatorAttribute", which will check that the given type derives from your base provider class/interface. You can of course add your own validators, so that in the rest of your code, you just "get" the configuration and you know everything's valid.
Multi-level settings hierarchy: you can play around with storing settings at the machine, application or user levels, which gives you a mechanism to handle default vs. user-specific settings. You also have APIs to load configurations from custom locations.
No duplication in config files: if you're using other .NET features like TraceSources and stuff, the configuration for that is already in the .config file (say you're troubleshooting a problem and you want to turn on some debug trace that's off by default... you do that by just modifying the .config). If you're using your own config file for your custom settings, then you end up with 2 configuration files, which is not so good.
There's probably other benefits, but that's what comes to mind so far.
It's just a recommended and easier way of reading and writing data to configuration files. Using XML DOM is too low level.
You can always get raw xml configuration from ConfigurationSection using section.SectionInformation.GetRawXml() if needed. Likewise use SetRawXml to set this.
There are a few gotchas though when using ConfigurationManager, for example when you load a config file using OpenMappedExeConfiguration, you get an in memory configuration which is "merged" and has sections from machine.config. You can check if a section came from the file you provided using section.ElementInformation.Source.Equals(source.FilePath).
Reference: MSDN
Related
This related question has an answer which describes including/referencing additional config files from the default config file: How to read values from multiple Configuration file in c# within a single project?
Is that the only (sensible) way to do this or does C# allow me to freely access different config files? Is there something inherently special about app.config?
My personal experience with Config files is that if you want to read them programatically or to add extra fields, etc, you have to work a lot. That is why I usually just create my own configuration code. It might sound as reinventing the wheel, but the configuration needs to be easily read and modified by people. Also its format might change. Depending on your config needs a simple text file or a json style config might be more accessible.
If you want to do it with .NET's method, the ConfigManager class allows you to open/change .config files, assuming you have all the elements described as classes somewhere.
What is the preferred way of reading an application's configuration file in .NET 4? I've seen several articles on how to do with .NET 2. I don't know if things have changed/improved with .NET 4.
The ConfigurationManager is still the preferred way of reading the application config and web config files.
To use it you will first need to add a reference in your project to System.Configuration.
Then you will need to add a reference to it in your class with:
using System.Configuration;
Once you have done this you will be able to access things like your AppSettings and ConnectionStrings by calling these static properties on the ConfigurationManager class.
e.g.
ConfigurationManager.AppSettings["settingname"];
Most developers seem to be happy with the string-based ConfigurationManager.AppSettings style of configuration, but there is another way: strongly typed configuration.
The MSDN reference is here: http://msdn.microsoft.com/en-us/library/8eyb2ct1.aspx
In a nutshell, you can define your own configuration setting section and have your own strongly typed configuration items in there. Amongst other things this
(as the name implies) can force use of enumerated options
allows you to define user-based or application-based settings
allows you to define defaults
The main downside is that it's a bit of a faff to get going as there's quite a bit of code to implement and test.
OK, so this is not the most useful question since I can't remember the feature in .net that does this. Basically, that's what I'm asking; what feature is this?
A year or so ago, I was working on a project and we used configuration files that mapped directly to a class using the specific attributes on the class members. This is not the standard app.config, but assemblyname.dll.xml instead.
Perhaps it's a feature within the unity framework? Just a stab in the dark.
It is not critical I figure this out today, but it is just weighing on my brain and annoys me that i can't remember!
thanks!
It's not the standard XML config, but it is built into .NET. Basically, XML serialization allows you to project an XML document from a hydrated class instance, that will map 1:1 to the class it came from and can be used to re-hydrate a new instance of that class.
This can, in the majority of cases, be done without much effort on your part. All that's usually necessary for XML serialization to work is that the object must have a public default constructor, and that all the state information you want to serialize must be public and read-write. In a few cases, some attributes are necessary to define certain behaviors, like derived classes in arrays of their parent class, and defining non-default names for field and property element tags.
One of the major uses of this is for custom configuration files as you stated; you can load the configuration from a persistent state by simply deserializing the file into an instance of the configuration object.
Article: MSDN How To Serialize an Object
This isn't part of the .Net bcl or Unity as far as I am aware. Perhaps it's some other third party or open source component? That being said, it wouldn't be too difficult to build something like this on your own using XmlSerialization.
.net allows for multi layered configuration.
Every machine has the machine.config file. each application has the app.config file (which gets renamed to applicationname.exe.config upon building), but each dll can also have it's own config file. so, if I have the following binaries in my executable folder:
flexitris.exe
flexitrisHelpers.dll
thirdPartyContent.dll
each of them can have their own config file:
flexitris.exe.config
flexitrisHelpers.dll.config
thirdPartyContent.dll.config
and all of them will be read at runtime and accessible using the normal System.Configuration namespace.
We have many environments and thinking of creating dynamic application configuration as part of CI. The configuration values will be stored in Database using WPF. Operation team manages the app for new app config entries.
The problem I am facing is how can I dynamically create the config and validate it? Opinions..? Thanks in advance.
If the number of configurations is finite and known (test, UAT, production desktop, production mobile, etc), you can take advantage of the configSource attribute found on the AppSettings, ConnectionStrings and ConfigSection elements. Here's the basic premise; create an AppSettings.xyz.config file for each configuration, where xyz is the name of the configuration ("local" "test", "uat", "prod", etc). Create a single app.config file that uses a <!ENTITY config "xyz"> definition, and has configSource attributes for various sections set similar to:
<appsettings configSource="appSettings.&config.config">
Now, in deployment logic, you change one thing; the string literal defined by the entity. This change is simple enough that you don't even really need XML parsing to make the change; just slurp the file into memory with a FileStream, find the entity definition, make the change and spit the new content back out into the file. If you're using an installer, you can control which child configs are installed, or just put them all out there for simplicity.
Take a look at T4. You can create a skeleton .config file with certain variables that are filled from the database to generate the environment-specific file.
I have a Solution with 3 projects in, each project needs access to certain settings. I'm looking for a way to have these setting values available to any project from 1 distinct source. I cant use the .Config file as that is relevent to that particular project.
I could use the database but have been told this is not good practice (Without an reason)
Any ideas?
You could do this:
create a solution.config in your solution folder
in each project's app.config, add this to your <appSettings> node:
<appSettings file="solution.config">
....
</appSettings>
You would have to put symbolic links to your common solution.config in each project folder - but you could have one single physical file that you share amongst the projects.
The <appSettings> node is the only one that allows that sort of "cummulative" settings - those from the file specified in the file= will be added to your app settings, but potentially overwritten by anything you specify explicitly in your app.config.
On the other hand, yes, of course, you could use the database. We do that, too, in most of our projects, since we typically do have access to the database, but not to the file system in the client's server machines. I don't see why that should necessarily be a bad thing - we have settings for DEV, TEST and PROD in a table - so you have all your settings in one place - and we pick those settings we need when we need them. Works just fine - of course, some settings like the connection strings to the database cannot be stored there - but the bulk of our config info is. Again: I really don't see any reason why this should be a bad choice per se - so unless your source can back his/her statement up with some facts and reasons, I'd ignore it.
You can define configSource attribute in a defined configSection, to reference an external file from which to load your properties.
Here you can find an example:
Is there any way for an App.config file to reference another full config file? (.NET)
You can also use a DB of course, but that would probably involve developing some kind of configuration console, since it's not a good practice to manage config attributes directly into DB.
Otherwise you can create your config file (an xml, or yaml for example) and create your own shared config parser.
I create a class to hold system-wide settings using either a Singleton pattern, or a Global instance (whichever you preference is).
If another project is in the solution, it can see the class (when references are added).
This also decouples the presentation of the settings from the storage mechanism (database, config file, custom XML file, whatever), and if you design to the interface, it makes unit testing more flexible, too.
You could add an entry into each projects .config file that points to the global one. You would need to read that in three places though.
Another solution that springs to mind is to put your common settings into their own assembly with it's own .config file. You then include that assembly in each of your projects. The .config file is read in the assembly and you can read out those values you need.
What kinds of settings?
You can use the system wide machine.config and web.config files for settings that apply across an entire machine.
\Windows\Microsoft.NET\Framework[64]\[version]\config\machine.config
\Windows\Microsoft.NET\Framework[64]\[version]\config\web.config
You could use the registry if you have access to it. Then all you would need is a class to read them out (and possiblty one to put them in) and each project could use that class to read them.
The major downside though is that you would have to add the settings to each machines registry that you run your solution on.