2011-03-17 78 views
1

我正在尝试创建一个使用C#的CSharpCodeProvider在运行时生成C#代码的脚本系统。这是一个我正在编写的简单的游戏引擎,用XNA 4.0编写。 目标是让用户能够通过C#修改游戏元素,而无需访问游戏引擎的任何细节(渲染代码,物理代码,网络等)。脚本在运行时由引擎编译为DLL。目前,我在引擎和已编译的脚本DLL之间建立了通信。 (我创建了一个Player.cs脚本,并且在编译之后,它能够从脚本DLL中调用我的引擎的“Engine.Print(”Foobar“);方法)引擎还能够使用脚本的方法(引擎遍历在编译后的脚本所定义的所有新类,并调用编译后的“OnCompile()”方法TargetInvocationException与CSharpCodeProvider生成的DLL

问题与脚本间通信的开始:我有2个脚本,库存和播放器:

Inventory.cs :

public class Inventory 
{ 
    int foobar; 

    public Inventory() 
    { 
     foobar = 42; 
    } 

    public static void OnCompile() 
    { 
     // This method exists in the Engine DLL, linked to this script 
     Engine.Print("OnCompile Inventory");  
    } 
} 

Player.cs:

using Scripts.Inventory; 

public class Player 
{ 
    Inventory inventory; 

    public Player() 
    { 
     //inventory = new Inventory(); 
     Engine.Print("Player created"); 
    } 


    public static void OnCompile() 
    { 
     Engine.Print("OnCompile Player"); 
     Player test = new Player(); 
    } 
} 

此代码的功能,调试输出打印:

OnCompile库存
OnCompile播放
Player创建

然而,一旦我去掉库存=新库存();在播放器的构造 调试输出如下:

OnCompile库存
OnCompile球员

未处理的异常:System.Reflection.TargetInvocationException:异常已通过调用的目标引发异常。 ---> System.IO.FileNotFoundException:无法加载文件或程序集'Inventory.cs,Version = 0.0.0.0,Culture = neutral,PublicKeyToken = null'或其依赖项之一。该系统找不到指定的文件。 () at Scripts.Player.Player.ctor() at Scripts.Player.Player.OnCompile()

我已经确保我的Player.cs.dll引用了Inventory.cs.dll。我的汇编代码如下:

public static bool Compile(string fileName, bool forceRecompile = false) 
    { 
     // Check to see if this assembly already exists. 
     // If it does, then just return a reference to it, unless 
     // it is told to forceRecompile, in which case 
     // it will delete the old, and continue compiling 
     if (File.Exists("./" + fileName + ".dll")) 
     { 
      if (forceRecompile) 
      { 
       File.Delete(fileName + ".dll"); 
      } 
      else 
      { 
       return true; 
      } 
     } 


     // Generate a name space name. this means removing the initial ./ 
     // of the path, and replacing all subsequent /'s with .'s 
     // Also removing the .cs at the end 

     // i.e: ./Scripts/Player.cs becomes 
     //  Scripts.Player 

     string namespaceName = ""; 

     if (fileName.LastIndexOf('.') != -1) 
     { 
      fileName = fileName.Remove(fileName.LastIndexOf('.')); 
     } 

     namespaceName = fileName.Replace('/', '.'); 
     namespaceName = namespaceName.Substring(2); 

     // Add references, starting with ScriptBase.dll. 
     // ScriptBase.dll is a helper library that provides 
     // access to debug functions such as Console.Write 

     List<string> references = new List<string>() 
     { 
      "./ScriptBase.dll", 
      "System.dll"  // TODO: remove later 
     }; 


     // Open the script file wit ha StreamReader 
     StreamReader fileStream; 
     string scriptSource = ""; 

     fileStream = File.OpenText("./" + fileName + ".cs"); 


     // Preprocess the script. This is important, as it resolves 
     // using statements, so that if a script references another 
     // script, it will have the dependency registered before 
     // compiling. 
     do 
     { 
      string line = fileStream.ReadLine(); 

      string[] words = line.Split(' '); 

      // Found a using statement: 
      if (words[0] == "using") 
      { 
       // Get the namepsace name: 
       string library = words[1]; 

       library = library.Remove(library.Length - 1); // get rid of semicolon 

       // Convert back to a path 
       library = library.Replace('.', '/'); 


       // See if the assembly exists, or we are forcing the recompilation 
       if (!File.Exists("./" + library + ".cs.dll") || forceRecompile) 
       { 
        // We need to compile it now. 
        // See if the script file exists... 
        if (File.Exists("./" + library + ".cs")) 
        { 
         // if it does, compile that, if it doesn't then we bail 
         if (!Compile("./" + library + ".cs", forceRecompile)) 
         { 
          return false; 
         } 
        } 
        else 
        { 
         return false; 
        } 
       } 
       // Now that it's compiled, and we need it link it with our reference list... 
       references.Add("./" + library + ".cs.dll"); 
      } 
      // Piece it back together as one string, line by line. 
      scriptSource = scriptSource + line + "\n"; 

     } while (!fileStream.EndOfStream); 


     fileStream.Close(); 

     // Automagically add our namepsace to the script, so the scriptor doesn't have to, also automatically 
     // include ScriptBase 
     // This is where Engine class is found for Print() debug method   

     string source = "using ScriptBase; namespace " + namespaceName + "{" + scriptSource + "}"; 


     // Set up the compiler: 
     Dictionary<string, string> providerOptions = new Dictionary<string, string> 
     { 
      { "CompilerVersion", "v3.5" } 
     }; 

     CSharpCodeProvider provider = new CSharpCodeProvider(providerOptions); 


     // Create compilation params... Here we link our references, and append ".cs.dll" to our file name 
     // So now for example, ./Scripts/Player.cs compiles to ./Script/Player.cs.dll 
     CompilerParameters compilerParams = new CompilerParameters(references.ToArray(), fileName + ".cs.dll") 
     { 
      GenerateInMemory = true, 
      GenerateExecutable = false, // compile as DLL 

     }; 

     // Compile and check errors 
     CompilerResults results = provider.CompileAssemblyFromSource(compilerParams, source); 
     if (results.Errors.Count != 0) 
     { 
      foreach (CompilerError error in results.Errors) 
      { 
       // Write out any errors found: 
       Console.WriteLine("Syntax Error in " + error.FileName + " (" + error.Line + "): " + error.ErrorText); 
      } 

      return false; 
     } 

     // Return our Script struct, which keeps all the information together, 
     // and registers it so that Script.GetCompiledScript("./Scripts/Player.cs.dll"); 
     // returns the compiled script, or null if it's never been compiled 

     Assembly.LoadFrom(fileName + ".cs.dll"); 

     foreach (Type type in results.CompiledAssembly.GetTypes()) 
     { 
      new ScriptClass(fileName + ".cs.dll", type); 
     } 

     return true; 
    } 
} 

我已经通过代码加强,并Inventory.cs按预期始终得到Player.cs之前编制,并正确添加到Inventory.cs.dll引用列表编译前的Player.cs。

我必须缺少一些东西,只是简单地链接引用列表中的DLL似乎不够用,错误提到没有找到文件Inventory.cs。我在哪里指定搜索源.cs的路径? (.cs.dll编译的脚本始终位于与.cs源代码脚本相同的路径中)

回答

1

您将需要为AppDomain.AssemblyResolve事件添加处理程序。在处理程序中,您可以将程序集名称映射到您用Assembly.LoadFrom()加载的程序集。

加载了Assembly.LoadFrom()的程序集属于所谓的loadfrom上下文。用Assembly.Load()加载的正常引用程序集和程序集属于加载上下文。程序集不会找到其他上下文中存在的自动引用的程序集。

在这种情况下,两个动态编译的程序集都会从上下文中加载到load中,因此它们也应该可以彼此对齐。但是,执行程序集存在于加载上下文中,因此无法在加载上下文中看到其他程序集。 results.CompiledAssembly.GetTypes()强制将程序集加载到加载上下文中,并抛出异常,因为程序集引用无法解析。需要使用AppDomain.AssemblyResolve事件来绑定来自另一个绑定上下文的程序集。

关于结合上下文的更多信息:http://blogs.msdn.com/b/suzcook/archive/2003/05/29/57143.aspx