动态装卸DLL示例－匪徒和炸弹

我来设计一个例子，我在D目录运行程序A（土匪）。然后望D目录丢文件（炸弹）过去，土匪判断该文件是否炸弹(包含实现了接口IBomb的类),如果是，则执行IBomb的Explode方法让炸弹爆炸，当然炸了以后就没有了，文件将被删除。

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接口定义--编译为Interface.dll 供炸弹和土匪引用。

using System; namespace Interface { public interface IBomb { void Explode(); } }

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炸弹定义--编译为ClassLibrary1.dll，准备交给土匪

using System; namespace ClassLibrary1 { public class Class1:Interface.IBomb { public void Explode() { Console.WriteLine("bo~~~"); } } }

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那么程序A，引爆炸弹而且能把炸弹扔掉的土匪--编译为AppDomainTest.exe

using System; using System.Reflection; namespace AppDomainTest { /// <summary> /// 动态装卸dll程序集示例 /// 这里用一个有趣的例子： /// /// 我把一个dll看作是炸弹，执行如下操作 /// 1、炸弹扔到程序运行目录中 /// 2、引爆炸弹 /// 3、炸弹消失 /// /// /// </summary> class Program { /// <summary> /// 使用FileSystemWatcher监视炸弹，如果有则引爆 /// </summary> /// <param name="args"></param> static void Main(string[] args) { Console.WriteLine("Press Any Key To Exit ..."); System.IO.FileSystemWatcher fsWatcher = new System.IO.FileSystemWatcher(); fsWatcher.Path =System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location); fsWatcher.Filter = "*.dll"; fsWatcher.EnableRaisingEvents = true; fsWatcher.Created += new System.IO.FileSystemEventHandler(fsWatcher_Created); Console.ReadKey(); } /// <summary> /// 如果有炸弹丢过来则引爆 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> static void fsWatcher_Created(object sender, System.IO.FileSystemEventArgs e) { InvokeExplode(e.FullPath); } /// <summary> /// 不能炸着自己，创建一个AppDomain... /// </summary> /// <param name="fileName"></param> public static void InvokeExplode(string fileName) { try { System.AppDomain app = System.AppDomain.CreateDomain(System.IO.Path.GetFileNameWithoutExtension(fileName)); System.Runtime.Remoting.ObjectHandle objLoader= app.CreateComInstanceFrom(System.Reflection.Assembly.GetExecutingAssembly().Location, "AppDomainTest.RemoteLoader"); RemoteLoader loader = objLoader.Unwrap() as RemoteLoader; loader.InvokeExplode(fileName); System.AppDomain.Unload(app); System.IO.File.Delete(fileName); } catch (Exception ex) { Console.WriteLine(ex.Message); } } } /// <summary> /// 在这里爆炸，注意这里的Assembly不能被外面访问 /// </summary> class RemoteLoader : MarshalByRefObject { public void InvokeExplode(string fileName) { Assembly assembly = Assembly.LoadFile(fileName); foreach (System.Type type in assembly.GetTypes()) { if (type.GetInterface(typeof(Interface.IBomb).FullName) != null) { object obj = assembly.CreateInstance(type.FullName,true); ((Interface.IBomb)obj).Explode(); } } } } }

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--这三个文件怎么玩儿呢？第一个不能玩儿，是给第二个和第三个引用的。

运行AppDomainTest.exe,然后把ClassLibrary1.dll扔到该运行目录。你应该看到如下输出之后ClassLibrary1.dll会自动消失。

Press Any Key To Exit ..
bo~~~

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如果把ClassLibrary1.dll改为

using System; namespace ClassLibrary1 { public class Class1:Interface.IBomb { public void Explode() { Console.WriteLine("bo~~~"); } } public class Class2 : Interface.IBomb { public void Explode() { Console.WriteLine("乒~~~~乓~~~"); } } }

扔到正在运行AppDomainTest.exe的目录中，AppDomainTest.exe将会输出

Press Any Key To Exit ...


bo~~~


bo~~~


乒~~~~乓~~~

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感兴趣就玩玩吧，注意assembly这玩艺可是请神容易送神难:p