.NET assembly Konfiguration in machine.config ignoriert

Question

Ich habe eine Situation, wo ich brauche laden zu können Assemblys im GAC auf der Grundlage ihrer Teilnamen. Um dies zu tun, habe ich folgendes zu meiner app.config-Datei hinzugefügt:

<runtime>
  <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
    <qualifyAssembly partialName="MyAssembly"
                     fullName= "MyAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=0123456789abcdef"/>
  </assemblyBinding>
</runtime>

Das funktioniert genau so, wie ich es will. Allerdings, wenn ich das gleiche Element in meiner Datei machine.config platzieren, so scheint es, um ignoriert zu werden, und ich FileNotFoundExceptions beim Versuch MyAssembly zu laden.

Im Folgenden ist die Montage Bindungsprotokoll, wenn das Element in meinem app.config ist, und die Bindung erfolgreich ist:

LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\Documents and Settings\jon_scheiding\My Documents\Source\Testing\Test Projects 1\Cmd\bin\Debug\Testers.Cmd.vshost.exe.config
LOG: Using machine configuration file from C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\config\machine.config.
LOG: Partial reference qualified from config file. New reference: MyAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=0123456789abcdef.
LOG: Post-policy reference: MyAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=0123456789abcdef
LOG: Found assembly by looking in the GAC.
LOG: Binding succeeds. Returns assembly from C:\WINDOWS\assembly\GAC_MSIL\MyAssembly\1.0.0.0__b20f4683c1030dbd\MyAssembly.dll.
LOG: Assembly is loaded in default load context.

Kontrast, dass mit dem Protokoll, wenn meine Konfiguration in machine.config ist, und die Bindung fehlschlägt:

LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\Documents and Settings\jon_scheiding\My Documents\Source\Testing\Test Projects 1\Cmd\bin\Debug\Testers.Cmd.vshost.exe.config
LOG: Using machine configuration file from C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\config\machine.config.
LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
LOG: Attempting download of new URL file:///C:/Documents and Settings/jon_scheiding/My Documents/Source/Testing/Test Projects 1/Cmd/bin/Debug/MyAssembly.DLL.
LOG: Attempting download of new URL file:///C:/Documents and Settings/jon_scheiding/My Documents/Source/Testing/Test Projects 1/Cmd/bin/Debug/MyAssembly/MyAssembly.DLL.
LOG: Attempting download of new URL file:///C:/Documents and Settings/jon_scheiding/My Documents/Source/Testing/Test Projects 1/Cmd/bin/Debug/MyAssembly.EXE.
LOG: Attempting download of new URL file:///C:/Documents and Settings/jon_scheiding/My Documents/Source/Testing/Test Projects 1/Cmd/bin/Debug/MyAssembly/MyAssembly.EXE.
LOG: All probing URLs attempted and failed.

Das Problem scheint die vierte Zeile zu sein „Politik zu diesem Zeitpunkt nicht referenzieren angewandt wird.“ Allerdings kann ich nur sehr wenig Dokumentation finden, was diese Meldung bedeutet, oder wie es zu lösen.

Wie kann ich den Rahmen meines Element zu erkennen?

Vielen Dank im Voraus!

Answer 1

Das Framework wird nicht gelesen qualifyAssebmly Konfiguration von machine.config, liest er es nur aus der Anwendungskonfigurationsdatei.

Das Framework hat Ihr runtim Element erkennen, aber es nicht das qualifyAssembly Element erkennen.

Answer 2

Ich kam zu diesem Bedarf wieder viel später, als wir einige Assemblys im GAC und Dinge wie NHibernate benötigt, um sich zu lösen. Anstatt jeden app.config all diese qualifyAssembly Elemente hinzufügen, der folgende Code ermöglicht es uns, sie zu unserem machine.config hinzuzufügen.

using System;
using System.Collections.Generic;
using System.Configuration;
using System.IO;
using System.Reflection;
using System.Xml;
using System.Xml.XPath;

namespace MyNamespace {

    /// <summary>
    /// Implements <see cref="IDisposable"/> to provide a scope for resolving
    /// assemblies described in the machine.config file with 
    /// &lt;qualifyAssembly&gt; elements.
    /// </summary>
    /// <remarks>
    /// Because the framework only respects &lt;qualifyAssembly&gt; at the
    /// application configuration level, this class provides similar
    /// functionality for this element at the machine configuration level.
    /// You can wrap a new instance of this class in a <b>using</b> statement
    /// to get resolution within a specific scope; or, you can call the 
    /// <see cref="AssemblyResolver.Attach()"/> method to get 
    /// resolution for the lifetime of the current <see cref="AppDomain"/>.
    /// </remarks>
    public sealed class AssemblyResolver : IDisposable {

        #region Private fields and implementation

        private static Dictionary<string, string> _qualifiedNames;

        private static Assembly ResolveAssembly(object sender, ResolveEventArgs args) {
            if(_qualifiedNames == null) {
                //
                // Lazily initialize short/long name mappings.
                //
                _qualifiedNames = BuildQualifiedNameList();
            }

            if(!_qualifiedNames.ContainsKey(args.Name)) {
                return null;
            }

            try {
                return Assembly.Load(_qualifiedNames[args.Name]);
            }
            catch(FileNotFoundException) {
                //
                // TODO: Should this exception be propogated?
                // It probably should not be hidden from the consumer
                // since it likely indicates a configuration error.
                //
                return null;
            }
        }

        private static Dictionary<string, string> BuildQualifiedNameList() {
            var dict = new Dictionary<string, string>(StringComparer.InvariantCultureIgnoreCase);

            //
            // Get runtime XML data
            //
            var xml = GetConfigXml(GetMachineRuntimeSection());
            if(xml == null) {
                return dict;
            }

            //
            // Iterate the qualifyAssembly elements and register in the list
            //
            var navigator = xml.CreateNavigator();
            foreach(XPathNavigator qualifyAssembly in navigator.Select("runtime/asm:assemblyBinding/asm:qualifyAssembly", CreateNamespaceManager())) {
                dict.Add(
                    qualifyAssembly.GetAttribute("partialName", string.Empty),
                    qualifyAssembly.GetAttribute("fullName", string.Empty));
            }

            return dict;
        }

        private static ConfigurationSection GetMachineRuntimeSection() {
            System.Configuration.Configuration machineConfig = ConfigurationManager.OpenMachineConfiguration();
            return machineConfig.GetSection("runtime") as ConfigurationSection;
        }

        private static IXPathNavigable GetConfigXml(ConfigurationSection runtimeSection) {
            var ignoreSection = runtimeSection as IgnoreSection;
            if(ignoreSection == null) {
                return null;
            }

            //
            // Cheat via Reflection to get the XML content of the config
            // section.
            //
            FieldInfo field = typeof(IgnoreSection).GetField("_rawXml", BindingFlags.Instance | BindingFlags.NonPublic);
            string rawXml = (string)field.GetValue(ignoreSection);
            return new XPathDocument(new StringReader(rawXml));
        }
        private static IXmlNamespaceResolver CreateNamespaceManager() {
            var nsmgr = new XmlNamespaceManager(new NameTable());
            nsmgr.AddNamespace("asm", "urn:schemas-microsoft-com:asm.v1");
            return nsmgr;
        }

        #endregion

        /// <summary>
        /// Creates a new <see cref="AssemblyResolver"/>.
        /// </summary>
        public AssemblyResolver() {
            AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(ResolveAssembly);
        }

        /// <summary>
        /// Removes the current <see cref="AssemblyResolver"/>
        /// from the <see cref="AppDomain"/>.
        /// </summary>
        public void Dispose() {
            AppDomain.CurrentDomain.AssemblyResolve -= new ResolveEventHandler(ResolveAssembly);
            GC.SuppressFinalize(this);
        }

        /// <summary>
        /// Provides qualified assembly resolution for the lifetime of the
        /// current <see cref="AppDomain"/>.
        /// </summary>
        public static void Attach() {
            Attach(AppDomain.CurrentDomain);
        }

        /// <summary>
        /// Provides qualified assembly resolution for the lifetime of an
        /// <see cref="AppDomain"/>.
        /// </summary>
        /// <param name="appDomain">
        /// The <see cref="AppDomain"/> to service.
        /// </param>
        public static void Attach(AppDomain appDomain) {
            appDomain.AssemblyResolve += new ResolveEventHandler(ResolveAssembly);
        }

    }
}

In den meisten Fällen beschränken wir den Umfang davon, indem es wie folgt aus:

using(new AssemblyResolver()) {
    //
    // NHibernate initialization or whatever
    //
}

Es kann auch in App-Startcode oder global.asax verwendet werden, und für die Lebensdauer der Anwendung bestehen, etwa so:

AssemblyResolver.Attach();
//
// or
//
AssemblyResolver.Attach(AppDomain.CurrentDomain);