I have learnt about custom configurations using the ConfigurationManager. For some reason you have to use the assembly reference in the section element of the app.config, otherwise the ConfigurationManager won't load the app.config. But in an ASP.NET app this works fine. Why?
Consider this custom configuration class:
namespace CustomConfiguration
{
class MySection : ConfigurationSection
{
[ConfigurationProperty("link", IsKey = true)]
public string Link
{
get => (string) this["link"];
set => this["link"] = value;
}
}
}
Using this app.config, I can easily get the link-attribute of myCustomSection in my program:
<configuration>
<configSections>
<section name="myCustomSection" type="CustomConfiguration.MySection, myAssembly" />
</configSections>
...
<myCustomSection link="link i can access in my code" >
</myCustomSection>
</configuration>
Removing the assembly reference in section-element of app.config will result in a ConfigurationErrorsException, because the ConfigurationManager can't load my CustomConfiguration.MySection class in it's own System.Configuration assembly.
E.g.:
<section name="myCustomSection" type="CustomConfiguration.MySection" />
But Microsofts documentation says I should be able to do this.
And in fact I can do this in an ASP.NET app. Not supplying an assembly-name in a type attribute for a section still works and system.configuration magically looks in the right app assembly. Why?
The ASP.NET hosting environment has a different assembly loading behaviour;
it loads all referenced assemblies (from then bin and GAC) at the moment of startup.
For that reason, the assembly of the CustomConfiguration.MySection section can be resolved automatically without specifying it in the type definition.
If you include the settings below in you web.config file, your assembly myAssembly will not be loaded at initial startup anymore.
Then it will also be required to specify the assembly part in the type definition via CustomConfiguration.MySection, myAssembly. Here you get the same behaviour as in a non web-based application.
<configuration>
<!-- ... -->
<system.web>
<compilation>
<assemblies>
<remove assembly="myAssembly" />
</assemblies>
</compilation>
</system.web>
<!-- ... -->
</configuration>
The referenced documentation in your question shows that a section (shown belown) can be declared in an app.config file (of non web-based application), but this will only work for the out-of-the-box supplied configuration classes/handlers, like eg. System.Configuration.SingleTagSectionHandler, which resides in the core System assemby (System.dll).
For all other (custom) sections, a full assembly-qualified name is required.
<configuration>
<configSections>
<section name="sampleSection"
type="System.Configuration.SingleTagSectionHandler" />
</configSections>
<sampleSection setting1="Value1"
setting2="value two"
setting3="third value" />
</configuration>
Related
Well I have following entries in my web config for SagePay Integration in an ASP.net MVC project.
<configuration>
<configSections>
<section name="SagePayConfiguration" type="System.Configuration.IgnoreSectionHandler" requirePermission="true" restartOnExternalChanges="true" allowLocation="true"/>
</configSections>
<SagePayConfiguration>
<!--Mandatory
Set to TEST for the Test Server and LIVE for the live environment-->
<add key="sagepay.api.env" value="TEST" />
.
.
</SagePayConfiguration>
However I am getting null when trying to access it from C# code.
SagePayConfiguration sagePayConfiguration = (SagePayConfiguration)System.Configuration.ConfigurationManager.GetSection("SagePayConfiguration");
Any help what I am missing here?
You must cast the ConfigrationItem to "System.Configuration.IgnoreSectionHandler" or set the type Attribute in web.conf to an existing Type in your assembly.
<section name="<SectionName>" type="<your type (FQN)>, <Assembly>" />
After that you can access it
YourType o = ((YourType)ConfigurationManager.GetSection("sectionName"));
EDIT:
The Type must derive from ConfigurationSection.
I would like to access the values in the ConfigurationManager.AppSettings object from a MEF plugin which has its own app.config file.
However, the keys from the app.config file are not present in AppSettings after the plugin is loaded.
The keys from the application loading the plugin are still present.
I noticed that using a Settings.settings file allows this behaviour, via the app.config file, so the file must be being loaded somehow.
My plugin looks like:
[Export(IPlugin)]
public class Plugin
{
public Plugin()
{
// reads successfully from app.config via Settings object
var value1 = Settings.Default["Key1"];
// returns null from app.config via ConfigurationManager
var value1 = ConfigurationManager.AppSettings["Key2"]
}
}
The app.config looks like this:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<configSections>
<sectionGroup name="applicationSettings" type="..." >
<section name="Plugin.Settings" type="..." />
</sectionGroup>
</configSections>
<appSettings>
<add key="Key2" value="Fails" />
</appSettings>
<applicationSettings>
<Plugin.Settings>
<setting name="Key1" serializeAs="String">
<value>Works</value>
</setting>
</Plugin.Settings>
</applicationSettings>
</configuration>
I can manually load the app.config file with:
var config = ConfigurationManager.OpenExeConfiguration("Plugin.dll");
var value = AppSettings.Settings["Key2"].Value
but this seems more like a workaround than a solution.
Is there a way to access a MEF plugin's <appSettings> directly, from inside the plugin?
If not, what is recommended?
By default the ConfigurationManager loads the .config for the entry assembly, i.e. the assembly that started the currently executing process.
The correct way to do this would be something like this:
[Export(IPlugin)]
public class Plugin
{
public Plugin()
{
var config = ConfigurationManager.OpenExeConfiguration(Assembly.GetExecutingAssembly().Location);
var value = config.AppSettings.Settings["Key2"].Value;
}
}
This would make the plugin automatically open the .config for the DLL it was compiled in, and fetch values from there.
I'd recommend you to use a dependency injection tool like Unity, in order to provide to your plug-ins the configuration they required. By proceeding in this way, your plug-ins will no longer need to reference System.Configuration.dll.
In a web.config file, I have a 3rd party settings section :
<configuration>
<configSections>
<sectionGroup name="TheProduct">
<section name="TheSection" type="TheCompany.TheProduct.TheSectionConfigurationHandler, TheCompany.TheProduct, Version=1.0.0.0, Culture=neutral, PublicKeyToken=b1e9bee111e9429c" />
</sectionGroup>
</configSections>
<TheProduct>
<TheSection somevalue="true" />
</TheProduct>
</configuration>
I want to read the value of this section from another application, but when I try to find the section, I always get null.
Here is my code :
var config = ConfigurationManager.OpenExeConfiguration(
#"C:\inetpub\wwwroot\TheProduct\web.config"
);
var settings = config.GetSection("TheProduct/TheSection"); // always null
What is the correct way to retrieve the config section ?
[Edit] If the calling app, which defines the same section, I can do :
var settings = ConfigurationManager.GetSection("TheProduct/TheSection");
and it's working. Mybe I'm not opening the web.config file using the correct way ?
Using the configuration manager requires that your application be able to instantiate the actual strongly-typed configuration objects. If you can't add a reference to the defining assembly, then your only choice is to use one of the XML api's (either System.Xml or System.Linq.Xml) to read it manually, in which case you won't be using the configuration manager at all.
Inside my web.config file I've got code like this:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
...
<section name="UninstallSurveySettings" type="dashboard.UninstallSurveyConfig" />
</configSections>
...
<UninstallSurveySettings>
<add key="fileLocation" value="C:\inetpub\wwwroot\output\" />
</UninstallSurveySettings>
...
</configuration>
I need to be able to access this field from my custom control. The control can be dropped into any website and needs to check that site's web.config for the fileLocation value in UninstallSurveySetting.
I've tried a couple different approaches with no luck. Any help on this would be greatly appreciated.
Much easier to use AppSettings.
Web.config:
<configuration>
<appSettings>
<add key="fileLocation" value="C:\inetpub\wwwroot\output\" />
</appSettings>
</configuration>
Code:
string location = System.Configuration.ConfigurationManager.AppSettings["fileLocation"];
If your section will become more complex, then:
var section = (NameValueFileSectionHandler)ConfigurationManager.GetSection("UninstallSurveySettings");
if (section != null)
{
// access section members
}
P.S.
Maybe you want to use ConfigurationSection class instead of handler.
In ASP.NET MVC 3 the tag cannot be a direct child of (it results in a configuration error).
How about adding your key to the section. Then you can easily access it via the ConfigurationManager.AppSettings collection.
using System.Configuration.ConfigurationManager and you will be able to get what you want from the web.config
I was able to solve this by creating a configuration class for it and placing this code in the web.config:
<section name="UninstallSurveyConfig" type="dashboard.UninstallSurveyConfig" />
..
<UninstallSurveyConfig dirFileLocation="C:\inetpub\wwwroot\build\output" webFileLocation="~/output" />
This is somewhat specific and difficult situation to explain, so bear with me.
I have created a UnityContainerExtension that is responsible for loading and configuring other .config files.
For example, my App.Config file looks like this:
<configuration>
<configSections>
<section name="unity" type="Microsoft.Practices.Unity.Configuration.UnityConfigurationSection, Microsoft.Practices.Unity.Configuration, Version=2.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
</configSections>
<unity xmlns="http://schemas.microsoft.com/practices/2010/unity">
<assembly name="SomeAssembly" />
<namespace name="SomeAssembly.SomeNameSpace" />
<container>
<extension type="ConfigSectionExtension" />
<extension type="TestExtension" />
</container>
</unity>
</configuration>
My first extension ConfigSectionExtension runs code (following) that loads in and configures the container with another .config file. ex.
var fileMap = new ExeConfigurationFileMap { ExeConfigFilename = "logging.config"};
Configuration configuration = ConfigurationManager.OpenMappedExeConfiguration( fileMap, ConfigurationUserLevel.None );
((UnityConfigurationSection)configuration.GetSection( "unity" )).Configure( Container );
This code runs fine, however the TestExtension extension in my config cannot be resolved after the Container has been configured with the logging.config file.
The specific response is
"The type name or alias TestExtension could not be resolved."
If I remove the code that loads and configures the logging.config file with the container, then both extensions are found. Is there any way to make this work?
This is essentially my approach to the problem of not being able to link together multiple .config files. If someone knows a better way to link .config files together for Unity, I would of course be open to that solution as well.
OK, I think I have an OK solution. For my extension I can just fully qualify the Type and it will work. ie.
<extension type="MediaInjectorUI.ContainerExtensions.ConfigSectionExtension, MediaInjectorUI" />
<extension type="MediaInjectorUI.ContainerExtensions.TestExtension, MediaInjectorUI" />
Maybe not the prettiest thing in the world, but itdoes the job.