ch6_3.cs

《c#技术内幕代码》

using System;
using System.Reflection;

interface IMyInterface
{
   void PrintAString( string s );
   void PrintAnInteger( int i );
   void PrintSomeNumbers( string desc, int i, double d);
   int  GetANumber( string s );
}

public class DoMyInterface : IMyInterface
{
   public DoMyInterface()
   {
   }
   public void PrintAString( string s )
   {
      Console.WriteLine( "PrintAString: {0}", s );
   }
   public void PrintAnInteger( int i )
   {
      Console.WriteLine( "PrintAnInteger: {0}", i );
   }
   public void PrintSomeNumbers( string desc, int i, double d)
   {
      Console.WriteLine("PrintSomeNumbers:");
      Console.WriteLine( "String: {0}", desc );
      Console.WriteLine( "Integer: {0}", i );
      Console.WriteLine("Double: {0}", d );
   }
   public int GetANumber( string s )
   {
      Console.WriteLine("GetANumber: {0}", s );
      return 34;
   }
   public int DoItAll(string s, int i, double d )
   {
      IMyInterface mi = (IMyInterface)this;
      mi.PrintSomeNumbers( s, i, d );
      return mi.GetANumber( s );
   }
}

public class CH6_3
{
   public static void DoDynamicInvocation( string assembly )
   {
       Assembly a = Assembly.LoadFrom( assembly );
       foreach( Type t in a.GetTypes() )
       {
          if ( t.IsClass == false )
	     continue;
	  if ( t.GetInterface("IMyInterface") == null )
	     continue;
	  Console.WriteLine("Creating instance of class {0}", t.FullName );
	  object obj = Activator.CreateInstance(t);
	  object[] args = {"Dynamic", 1, 98.6};
	  object result;
	  Console.WriteLine("Invoking method DoItAll dynamically");
	  try
	  {
	     result = t.InvokeMember("DoItAll",
	                      BindingFlags.Default | BindingFlags.InvokeMethod,
		   	      null,
			      obj,
			      args );
             Console.WriteLine("Result of dynamic call: {0}", result );
	     
             // Call an interface method
	     object[] args2 = {12345};
	     t.InvokeMember("PrintAnInteger",
	                      BindingFlags.Default | BindingFlags.InvokeMethod,
		   	      null,
			      obj,
			      args2 );
	     
          }
	  catch ( Exception e )
	  {
	     Console.WriteLine("Exception: {0}", e );
	  }
       }
   }
   public static void Main(string[] args)
   {
      DoMyInterface dmi = new DoMyInterface();
      dmi.PrintSomeNumbers("PrintEm", 1, 12.45 );
      int i = dmi.GetANumber("GiveMeOne");
      Console.WriteLine("I = {0}", i );
      
      DoDynamicInvocation(args[0]);
   }
}