从动态创建的对象加载程序集，并投它的接口（.NET 2.0） [英] Create object from dynamically load assembly and cast it to interface (.NET 2.0)

问题描述

我有一个动态加载大会的问题，铸造它的接口。哪里是我的错？

I have a problem with dynamically loaded assemblys and casting it to interface. Where is my mistake?

主要的应用程序（加载插件）：

Main app (load plugins):

namespace Console_IFce_Test
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Press any key to find IPlugin library...");
            Console.ReadKey();            

            string[] files = Directory.GetFiles(Directory.GetCurrentDirectory(), "*.dll");
            Console.WriteLine("Loading assembly: {0}", Path.GetFileName(files[0]));

            Assembly asm = Assembly.LoadFrom(files[0]);
            //Trying this, but still have problems
            //Assembly asm = Assembly.Load(File.ReadAllBytes(files[0])); 

            foreach (Type t in asm.GetTypes())
            {
                Console.WriteLine("Searching in type {0}... ", t.FullName);

                foreach (Type iface in t.GetInterfaces())
                {
                    Console.WriteLine("Interface found: {0}", iface.FullName);
                }

                if (t is IPlugin)
                {
                    Console.WriteLine("1 - IPlugin found!");
                    IPlugin plugin = (IPlugin)Activator.CreateInstance(t);
                    return;
                }

                if (typeof(IPlugin).IsAssignableFrom(t))
                {
                    Console.WriteLine("2 - IPlugin found!");
                    IPlugin plugin = (IPlugin)Activator.CreateInstance(t);
                    return;
                }
            }

            Console.WriteLine("All operations done! Press any key to exit...");
            Console.ReadKey();
        }
    }
}

接口：

namespace Console_IFce_Test
{
    interface IPlugin
    {
        int GetZero();
    }
}

和插件：

namespace Library
{
    public class Plugin : Console_IFce_Test.IPlugin
    {
        public int GetZero()
        {
            return 0;
        }
    }
}

在以.exe目录 - 只有1 .dll文件（插件）。因此，它的输出：

In directory with .exe - only 1 .dll (plugin). So, it's output:

Press any key to find IPlugin library... 
Loading assembly: Library.dll 
Searching in type Console_IFce_Test.IPlugin... 
Searching in type Library.Plugin... 
Interface found: Console_IFce_Test.IPlugin 
All operations done! Press any key to exit...

您看，该程序发现IPlugin界面组件，但是当我试图把它与接口相比较（二条件语句） - 他们返回false。如果我试图手动施放它 - 它返回异常不能投

You see, that program found IPlugin interface in assembly, but when i trying to compare it with interface (two conditional statements) - they return false. And if i trying to manually cast it - it returns exception "Can't cast".

我发现了类似的问题：<一href="http://stackoverflow.com/questions/3623358/two-types-not-equal-that-should-be/3624044#3624044">Two类型不等于应该和答案写作者：

I found similar problem: Two Types not equal that should be , and author of answer write:

在同一类/由不同的应用程序域[.NET]或类加载类型   装载机【JAVA]不会比较平等的，不分配给/从   彼此直接

The same class / type loaded by different app domains [.NET] or class loaders [Java] will not compare equal and are not assignable to/from each other directly.

但我不明白我应该怎么办？而如何？

But i can't understand what should i do? And how?

推荐答案

您需要以某种方式使.NET加载组件，以相同的情况下才能够做到的类型之间的倒在这些程序集。

You need to somehow make .NET to load the assemblies to the same context to be able to do a cast between the types in those assemblies.

1-把组件在应用路径或GAC使得负载（不是LoadFrom）函数会发现它

1- Put the assembly in the application path or GAC so that the Load (not the LoadFrom) function will find it.

2 - 创建一个应用程序域和所做的工作都在那里。你可以完全控制那些正在寻找一个应用程序域的组件。

2- Create an app domain and do all of the work there. You can fully control where the assemblies are being searched for an app domain.

3使用外接的模式。

阅读这篇文章以了解更多有关你的选择：最佳实践集加载

Read this article to learn more about your options: Best Practices for Assembly Loading

这篇关于从动态创建的对象加载程序集，并投它的接口（.NET 2.0）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！