I have the need to store some application specific configuration data to be
used by a class library and or a windows service. I would like to do this
in a fashion similar to the way we do with applications and web services
without having to use the machine.config file.
I know that I could use the code below to do this but the problem then
becomes that when using a shared assembly both the assembly and the config
file need to be put in the GAC. I do not want operations to have to GAC
after changes to the config.
Any advice, links or samples would be greatly appreciated. Thank you.
using System;
using System.Reflecti on;
using System.Collecti ons;
using System.Xml;
using System.Configur ation;
// AssemblySetting s usage:
//
// If you know the keys you're after, the following is probably
// the most convenient:
//
// AssemblySetting s settings = new AssemblySetting s();
// string someSetting1 = settings["someKey1"];
// string someSetting2 = settings["someKey2"];
//
// If you want to enumerate over the settings (or just as an
// alternative approach), you can do this too:
//
// IDictionary settings = AssemblySetting s.GetConfig();
//
// foreach( DictionaryEntry entry in settings )
// {
// // Use entry.Key or entry.Value as desired...
// }
//
// In either of the above two scenarios, the calling assembly
// (the one that called the constructor or GetConfig) is used
// to determine what file to parse and what the name of the
// settings collection element is. For example, if the calling
// assembly is c:\foo\bar\Test Lib.dll, then the configuration file
// that's parsed is c:\foo\bar\Test Lib.dll.config, and the
// configuration section that's parsed must be named <assemblySettin gs>.
//
// To retrieve the configuration information for an arbitrary assembly,
// use the overloaded constructor or GetConfig method that takes an
// Assembly reference as input.
//
// If your assembly is being automatically downloaded from a web
// site by an "href-exe" (an application that's run directly from a link
// on a web page), then the enclosed web.config shows the mechanism
// for allowing the AssemblySetting s library to download the
// configuration files you're using for your assemblies (while not
// allowing web.config itself to be downloaded).
//
// If the assembly you are trying to use this with is installed in, and
loaded
// from, the GAC then you'll need to place the config file in the GAC
directory where
// the assembly is installed. On the first release of the CLR, this
directory is
// <windir>\assemb ly\gac\libName\ verNum__pubKeyT oken]]>. For example,
// the assembly "SomeLib, Version=1.2.3.4 , Culture=neutral ,
PublicKeyToken= abcd1234"
// would be installed to the c:\winnt\assemb ly\gac\SomeLib\ 1.2.3.4__abcd12 34
diretory
// (assuming the OS is installed in c:\winnt). For future versions of the
CLR, this
// directory scheme may change, so you'll need to check the
<code>CodeBas e</code> property
// of a GAC-loaded assembly in the debugger to determine the correct
directory location.
//
public class AssemblySetting s
{
private IDictionary settings;
public AssemblySetting s()
: this(Assembly.G etCallingAssemb ly())
{
}
public AssemblySetting s( Assembly asm )
{
settings = GetConfig(asm);
}
public string this[ string key ]
{
get
{
string settingValue = null;
if( settings != null )
{
settingValue = settings[key] as string;
}
return(settingV alue == null ? "" : settingValue);
}
}
public static IDictionary GetConfig()
{
return GetConfig(Assem bly.GetCallingA ssembly());
}
public static IDictionary GetConfig( Assembly asm )
{
// Open and parse configuration file for specified
// assembly, returning collection to caller for future
// use outside of this class.
//
try
{
string cfgFile = asm.CodeBase + ".config";
const string nodeName = "assemblySettin gs";
XmlDocument doc = new XmlDocument();
doc.Load(new XmlTextReader(c fgFile));
XmlNodeList nodes = doc.GetElements ByTagName(nodeN ame);
foreach( XmlNode node in nodes )
{
if( node.LocalName == nodeName )
{
DictionarySecti onHandler handler = new
DictionarySecti onHandler();
return (IDictionary)ha ndler.Create(nu ll, null, node);
}
}
}
catch (Exception e)
{
Console.WriteLi ne ("Error: " + e.Message);
}
return(null);
}
}
