Question

我需要在另一个域中加载.dll（插件）。在主应用程序中，我对插件类型一无所知，只是他们用一些方法实现了通用接口ICommonInterface。因此，这段代码无济于事，因为我无法创建具有接口类型的实例。

AppDomain domain = AppDomain.CreateDomain("New domain name");
//Do other things to the domain like set the security policy

string pathToDll = @"C:\myDll.dll"; //Full path to dll you want to load
Type t = typeof(TypeIWantToLoad);
TypeIWantToLoad myObject = (TypeIWantToLoad)domain.CreateInstanceFromAndUnwrap(pathToDll, t.FullName);

我的问题是我如何在新域中加载程序集并获取实例，如果我只知道实现我想要创建的类型的接口名称。

更新：这是我的代码： MainLib.dll

namespace MainLib
{
public interface ICommonInterface
{
    void ShowDllName();
}
}

PluginWithOutException.dll

namespace PluginWithOutException
{
public class WithOutException : MarshalByRefObject, ICommonInterface
{
    public void ShowDllName()
    {
        Console.WriteLine("PluginWithOutException");
    }
}
}

PluginWithException.dll

namespace PluginWithException
{
public class WithException : MarshalByRefObject, ICommonInterface
{
    public void ShowDllName()
    {
        Console.WriteLine("WithException");
        throw new NotImplementedException();
    }
}
}

主要应用：

        static void Main(string[] args)
    {
        string path = @"E:\Plugins\";
        string[] assemblies = Directory.GetFiles(path);

        List<string> plugins = SearchPlugins(assemblies);

        foreach (string item in plugins)
        {
            CreateDomainAndLoadAssebly(item);
        }

        Console.ReadKey();
    }

    public static List<string> SearchPlugins(string[] names)
    {
        AppDomain domain = AppDomain.CreateDomain("tmpDomain");
        domain.Load(Assembly.LoadFrom(@"E:\Plugins\MainLib.dll").FullName);
        List<string> plugins = new List<string>();

        foreach (string asm in names)
        {
            Assembly loadedAssembly = domain.Load(Assembly.LoadFrom(asm).FullName);

            var theClassTypes = from t in loadedAssembly.GetTypes()
                                where t.IsClass &&
                                      (t.GetInterface("ICommonInterface") != null)
                                select t;
            if (theClassTypes.Count() > 0)
            {
                plugins.Add(asm);
            }
        }
        AppDomain.Unload(domain);
        return plugins;
    }

插件和主应用程序都引用了MainLib.dll。主要目的是不在默认域中加载程序集，而是将它们加载到另一个域，因此当我不需要它们时，我只需卸载（）域并从应用程序卸载所有插件。

现在异常是字符串FileNotFoundException, Could not load file or assembly 'PluginWithException, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.)上的Assembly loadedAssembly = domain.Load(Assembly.LoadFrom(asm).FullName);（我试图加载名为PluginWithException的插件），我删除了插件中的所有依赖项，exept系统，我加载了System.dll这个域（它加载正确，它在域中），但仍然无法将插件加载到域中。我还检查过，PluginWithException有2个依赖项--mscorlib和MainLib，并且所有这些都加载到了这个域。

更新：Here我更详细地询问了这个问题。

Answer 1

我不确定这是否是你需要的，我会尽力帮助你。这是我如何加载插件程序集。我使用一个帮助器类来管理新的AppDomain和该程序集上的类的实例。这是助手类：

[Serializable, ClassInterface(ClassInterfaceType.AutoDual)]
class helperDomain<T>: MarshalByRefObject where T: class
{
    #region private
    private AppDomain _app_domain;
    private AppDomainSetup _app_domain_info;

    private string _assembly_class_name;
    private string _assembly_file;
    private string _assembly_file_name;
    private T _inner_class;
    private bool _load_ok;
    private string _loading_errors;
    private string _path;
    #endregion

    #region .ctor
    public helperDomain(string AssemblyFile, 
       string configFile = null, string domainName)
    {
        this._load_ok = false;
        try
        {
            this._assembly_file = AssemblyFile; //full path to assembly
            this._assembly_file_name = System.IO.Path.GetFileName(this._assembly_file); //assmbly file name
            this._path = System.IO.Path.GetDirectoryName(this._assembly_file); //get root directory from assembly path 
            this._assembly_class_name = typeof(T).ToString(); //the class name to instantiate in the domain from the assembly
            //start to configure domain
            this._app_domain_info = new AppDomainSetup();
            this._app_domain_info.ApplicationBase = this._path;
            this._app_domain_info.PrivateBinPath = this._path;
            this._app_domain_info.PrivateBinPathProbe = this._path;
            if (!string.IsNullOrEmpty(configFile))
            {
                this._app_domain_info.ConfigurationFile = configFile;
            }
            //lets create the domain
            this._app_domain = AppDomain.CreateDomain(domainName, null, this._app_domain_info);
            //instantiate the class
            this._inner_class = (T) this._app_domain.CreateInstanceFromAndUnwrap(this._assembly_file, this._assembly_class_name);
            this._load_ok = true;
        }
        catch (Exception exception)
        {
            //There was a problema setting up the new appDomain
            this._load_ok = false;
            this._loading_errors = exception.ToString();
        }
    }
    #endregion


    #region public properties
    public string AssemblyFile
    {
        get
        {
            return _assembly_file;
        }
    }

    public string AssemblyFileName
    {
        get
        {
            return _assembly_file_name;
        }
    }

    public AppDomain AtomicAppDomain
    {
        get
        {
            return _app_domain;
        }
    }

    public T InstancedObject
    {
        get
        {
            return _inner_class;
        }
    }

    public string LoadingErrors
    {
        get
        {
            return _loading_errors;
        }
    }

    public bool LoadOK
    {
        get
        {
            return _load_ok;
        }
    }

    public string Path
    {
        get
        {
            return _path;
        }
    }
    #endregion
}

然后加载插件（每个插件在不同的文件夹中）。

foreach(string pluginassemblypath in pluginspaths)
{ 
    //Each pluginassemblypath (as it says..) is the full path to the assembly
    helperDomain<IPluginClass> isoDomain = 
        helperDomain<IPluginClass>(pluginassemblypath, 
             pluginassemblypath + ".config", 
             System.IO.Path.GetFileName(pluginassemblypath) + ".domain");
    if (isoDomain.LoadOK)
    {
       //We can access instance of the class (.InstancedObject)
       Console.WriteLine("Plugin loaded..." + isoDomain.InstancedObject.GetType().Name);
    }
    else
    {
       //Something happened...
       Console.WriteLine("There was en error loading plugin " + 
            pluginassemblypath + " - " + helperDomain.LoadingErrors);
    }
}

希望它会帮助你......

Answer 2

这个问题似乎与你想做的事情有关。

How to Load an Assembly to AppDomain with all references recursively?

加载程序集后，可以使用Assembly.GetTypes()并迭代查找实现接口的类型。

将DLL加载到具有已知唯一公共接口的单独AppDomain中

2 个答案: