C DLL config file

Question

Im trying to add an app config file to my DLL  but all attempts have failed    According to MusicGenesis in  Putting configuration information in a DLL  this should not be a problem  So obviously I m doing something wrong     The following code should return my ConnectionString from my DLL   return ConfigurationManager AppSettings  ConnectionString      However  when I copy the app config file to my console application  it works fine   Any ideas

User · Answer

The full solution is not often found in one place ...

1) Create an app config file and name it "yourDllName.dll.config"
2) Right click on the config file created above in VS Solution Explorer, click properties
--- set "Build Action" = Content
--- set "Copy To Output Directory" = Always
3) Add an appSettings section to the configuration file (yourDllName.dll.config) with your yourKeyName and yourKeyValue

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings>
    <add key="yourKeyName" value="yourKeyValue"/>
  </appSettings>
</configuration>

4) Add System.Configuration to your dll/class/project references
5) Add the using statements to your code where you intend to access the config setting

using System.Configuration;
using System.Reflection;

6) To access the value

string keyValue = ConfigurationManager.OpenExeConfiguration(Assembly.GetExecutingAssembly().Location).AppSettings.Settings["yourKeyName"].Value;

7) rejoice, it works

IMHO, this should only be used when developing a new dll/library.

#if (DEBUG && !FINALTESTING)
   string keyValue = ConfigurationManager.OpenExeConfiguration...(see 6 above)
#else
   string keyValue = ConfigurationManager.AppSettings["yourKeyName"];
#endif

The config file ends up being a great reference, for when you add the dll's appSettings to your actual application.

User · Answer

If you re using libraries that look up a large amount of configation behind-the-scenes  such as WCF  you might consider doing this   AppDomain CurrentDomain SetData  APP CONFIG FILE    MyWcfClientWrapper dll config      Or in PowerShell    AppDomain   CurrentDomain SetData  APP CONFIG FILE    MyWcfClientWrapper dll config     IMO this technique is a code smell and is really only suitable for use in ad hoc scripting   If you find yourself wanting to do this in production code  maybe it s time for an architectural review   The following is NOT recommended  As a technical curiosity  here s a variation on the theme   You can create a static constructor inside one of the classes housed in the DLL  and make this call from there   I wouldn t recommend doing this except as a last resort

User · Answer

It is not trivial to create a  NET configuration file for a  DLL  and for good reason   The  NET configuration mechanism has a lot of features built into it to facilitate easy upgrading updating of the app  and to protect installed apps from trampling each others configuration files   There is a big difference between how a DLL is used and how an application is used   You are unlikely to have multiple copies of an application installed on the same machine for the same user   But you may very well have 100 different apps or libraries all making use of some  NET DLL   Whereas there is rarely a need to track settings separately for different copies of an app within one user profile  it s very unlikely that you would want all of the different usages of a DLL to share configuration with each other   For this reason  when you retrieve a Configuration object using the  normal  method  the object you get back is tied to the configuration of the App Domain you are executing in  rather than the particular assembly   The App Domain is bound to the root assembly which loaded the assembly which your code is actually in   In most cases this will be the assembly of your main  EXE  which is what loaded up the  DLL   It is possible to spin up other app domains within an application  but you must explicitly provide information on what the root assembly of that app domain is   Because of all this  the procedure for creating a library-specific config file is not so convenient   It is the same process you would use for creating an arbitrary portable config file not tied to any particular assembly  but for which you want to make use of  NET s XML schema  config section and config element mechanisms  etc   This entails creating an ExeConfigurationFileMap object  loading in the data to identify where the config file will be stored  and then calling ConfigurationManager OpenMappedExeConfiguration to open it up into a new Configuration instance   This will cut you off from the version protection offered by the automatic path generation mechanism   Statistically speaking  you re probably using this library in an in-house setting  and it s unlikely you ll have multiple apps making use of it within any one machine user   But if not  there is something you should keep in mind   If you use a single global config file for your DLL  regardless of the app that is referencing it  you need to worry about access conflicts   If two apps referencing your library happen to be running at the same time  each with their own Configuration object open  then when one saves changes  it will cause an exception next time you try to retrieve or save data in the other app   The safest and simplest way of getting around this is to require that the assembly which is loading your DLL also provide some information about itself  or to detect it by examining the App Domain of the referencing assembly   Use this to create some sort of folder structure for keeping separate user config files for each app referencing your DLL   If you are certain you want to have global settings for your DLL no matter where it is referenced  you ll need to determine your location for it rather than  NET figuring out an appropriate one automatically   You ll also need to be aggressive about managing access to the file   You ll need to cache as much as possible  keeping the Configuration instance around ONLY as long as it takes to load or to save  opening immediately before and disposing immediately after   And finally  you ll need a lock mechanism to protect the file while it s being edited by one of the apps that use the library

User · Answer

I had the same problem and searched the web for several hours but I couldn t find any solution so I made my own  I wondered why the  net configuration system is so inflexible   Background  I want to have my DAL dll to have its own config file for database and DAL settings  I also need the app config for Enterprise Library and its own configurations  So I need both the app config and dll config   What I did not wanted to do is pass-through every property setting from the app to my DAL layer   to bend the  AppDomain CurrentDomain SetupInformation ConfigurationFile  is not possible because I need it for the normal app config behavior   My requirements point of views were    NO manual copy of anything from ClassLibrary1 dll config to WindowsFormsApplication1 exe config because this is unreproducible for other developers  retain the usage of strong typing  Properties Settings Default NameOfValue   Settings behavior  because I think this is a major feature and I didn t want to lose it I found out the lack of ApplicationSettingsBase to inject your own custom config file or management  all necessary fields are private in these classes  the usage of  configSource  file redirection is not possible because we would have to copy rewrite the ClassLibrary1 dll config and provide several XML files for several sections  I also didn t like this  I didn t like to write my own SettingsProvider for this simple task as MSDN suggests because I thought that simply would be too much I only need sections applicationSettings and connectionStrings from the config file   I came up with modifying the Settings cs file and implemented a method that opens the ClassLibrary1 dll config and reads the section information in a private field  After that  I ve overriden  this string propertyName   so the generated Settings Desginer cs calls into my new Property instead of the base class  There the setting is read out of the List    Finally there is the following code   internal sealed partial class Settings       private List lt ConfigurationElement gt  list            lt summary gt          Initializes a new instance of the  lt see cref  Settings   gt  class           lt  summary gt      public Settings                 this OpenAndStoreConfiguration                    lt summary gt          Opens the dll config file and reads its sections into a private List of ConfigurationElement           lt  summary gt      private void OpenAndStoreConfiguration                 string codebase   System Reflection Assembly GetExecutingAssembly   CodeBase          Uri p   new Uri codebase           string localPath   p LocalPath          string executingFilename   System IO Path GetFileNameWithoutExtension localPath           string sectionGroupName    applicationSettings           string sectionName   executingFilename     Properties Settings           string configName   localPath     config           ExeConfigurationFileMap fileMap   new ExeConfigurationFileMap            fileMap ExeConfigFilename   configName          Configuration config   ConfigurationManager OpenMappedExeConfiguration fileMap  ConfigurationUserLevel None               read section of properties         var sectionGroup   config GetSectionGroup sectionGroupName           var settingsSection    ClientSettingsSection sectionGroup Sections sectionName           list   settingsSection Settings OfType lt ConfigurationElement gt    ToList                read section of Connectionstrings         var sections   config Sections OfType lt ConfigurationSection gt             var connSection    from section in sections                            where section GetType      typeof ConnectionStringsSection                             select section  FirstOrDefault   as ConnectionStringsSection          if  connSection    null                        list AddRange connSection ConnectionStrings Cast lt ConfigurationElement gt                                lt summary gt          Gets or sets the  lt see cref  System Object   gt  with the specified property name           lt  summary gt           lt value gt  lt  value gt      public override object this string propertyName                get                       var result    from item in list                          where Convert ToString item ElementInformation Properties  name   Value     propertyName                          select item  FirstOrDefault                if  result    null                                if  result ElementInformation Type    typeof ConnectionStringSettings                                         return result ElementInformation Properties  connectionString   Value                                    else if  result ElementInformation Type    typeof SettingElement                                         return result ElementInformation Properties  value   Value                                              return null                       ignore         set                       base propertyName    value                    You just will have to copy your ClassLibrary1 dll config from the ClassLibrary1 output directory to your application s output directory  Perhaps someone will find it useful

User · Answer

you can use this code   using System  using System Collections Generic  using System Linq  using System Runtime InteropServices  using System Text  using System Threading Tasks   namespace GClass1    Guid  D6F88E95-8A27-4ae6-B6DE-0542A0FC7039     InterfaceType ComInterfaceType InterfaceIsIDispatch   public interface  GesGasConnect        DispId 1       int SetClass1Ver string version         Guid  13FE32AD-4BF8-495f-AB4D-6C61BD463EA4     ClassInterface ClassInterfaceType None    ProgId  InterfacesSMS Setting    public class Class1    Class1       public Class1             public int SetClass1 string version                return  DateTime Today Day

User · Answer

When using ConfigurationManager  I m pretty sure it is loading the process AppDomain configuration file  app config   web config   If you want to load a specific config file  you ll have to specifically ask for that file by name     You could try   var config   ConfigurationManager OpenExeConfiguration  foo dll    config ConnectionStrings   etc

User · Answer

As Marc says  this is not possible  although Visual Studio allows you to add an application configuration file in a class library project    You might want to check out the AssemblySettings class which seems to make assembly config files possible

User · Answer

It confusing to mock a  quot real quot  application configuration file  I suggest you roll your own because it is quite easy to parse an XML file using e g  LINQ  For example create an XML file MyDll config like below and copy it alongside the DLL  To Keep it up to date set its property in Visual Studio to  quot Copy to Output Directory quot   lt  xml version  quot 1 0 quot  encoding  quot utf-8 quot    gt    lt configuration gt     lt setting key  quot KeyboardEmulation quot  value  quot Off quot  gt  lt  setting gt    lt  configuration gt   In your Code read it like this      XDocument config   XDocument Load  quot MyDll config quot        var settings   config Descendants  quot setting quot   Select s   gt  new   Key   s Attribute  quot key quot   Value  Value   s Attribute  quot value quot   Value         bool keyboardEmulation   settings First s   gt  s Key     quot KeyboardEmulation quot   Value     quot On quot

User · Answer

For a dll  it should not depend on configuration as configuration is owned by application and not by dll    This is explained at here

User · Answer

ConfigurationManager AppSettings returns the settings defined for the application  not for the specific DLL  you can access them but it s the application settings that will be returned   If you re using you dll from another application then the ConnectionString shall be in the app settings of the application

User · Answer

In this post a similar problem was discussed and solve my problem How to load a separate Application Settings file dynamically and merge with current settings  might be helpfu

User · Answer

Seems like this config files are really confusing to clarify as their behaviour changes from the dev environment to deployment  Apparently a DLL can have its own config file  but once you copy and paste the dll  together with their config file  elsewhere  the whole thing stopped working   The only solution is to manually merge the app config files into a single file  which will only be used by the exec  For e g  myapp exe will have a myapp exe config file that contains all settings for all dlls used by myapp exe  I m using VS 2008

User · Answer

if you want to read settings from the DLL s config file but not from the the root applications web config or app config use below code to read configuration in the dll   var appConfig   ConfigurationManager OpenExeConfiguration Assembly GetExecutingAssembly   Location   string dllConfigData   appConfig AppSettings Settings  dllConfigData   Value

User · Answer

I know this is late to the party  however I thought I would share the solution I use for DLL s   I am more of the K I S S  school of thinking  so when I have a  NET DLL that wants to store external data points that control how it works or where it goes  etc  I simply create a  config  class that has only public properties that store all the data points it needs and that I would like to be able to have controlled external to the DLL to prevent recompiling it to make the changes   Then I use  Net s XML Serializing to save and load the object representation of the class to a file   There are a lot of ways then to handle reading it and accessing it  from a Singleton  a static utility class  to extension methods  etc   This depends on how your DLL is structured and what method will fit your DLL best

User · Answer

I ve found what seems like a good solution to this issue  I am using VS 2008 C   My solution involves the use of distinct namespaces between multiple configuration files  I ve posted the solution on my blog  http   tommiecarter blogspot com 2011 02 how-to-access-multiple-config-files-in html   For example   This namespace read writes dll settings   var x   company dlllibrary Properties Settings Default SettingName  company dlllibrary Properties Settings Default SettingName   value    This namespace read writes the exe settings   company exeservice Properties Settings Default SettingName   value  var x   company exeservice Properties Settings Default SettingName    There are some caveats mentioned in the article  HTH

User · Answer

Since the assembly resides in a temporary cache  you should combine the path to get the dll s config   var appConfig   ConfigurationManager OpenExeConfiguration      Path Combine Environment CurrentDirectory  Assembly GetExecutingAssembly   ManifestModule Name

User · Answer

you are correct  you can read the config file of a dll  I struggled with this for a day until i found out that the my config file was the issue  See my code below  it was able to run           ExeConfigurationFileMap map   new ExeConfigurationFileMap            map ExeConfigFilename   Assembly GetExecutingAssembly   Location     config           Configuration libConfig   ConfigurationManager OpenMappedExeConfiguration map  ConfigurationUserLevel None           AppSettingsSection section    libConfig GetSection  appSettings   as AppSettingsSection           Console WriteLine section Settings  dnd shortcodes   Value     my Plugin1 dll config looked as below    lt  xml version  1 0  encoding  utf-8    gt   lt configuration gt    lt appSettings gt     lt add key  cmd location  value  http         gt     lt add key  dnd shortcodes  value  142 145 146 157 165 167 168 171 173 176 178 404 40   gt    lt  appSettings gt   lt  configuration gt    I found out that my config file lacked the  lt appSettings gt  tag  so look around  your issue could have been different but not so far from mine

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