我正在尝试创建一个脚本系统，该系统使用C＃的CSharpCodeProvider在运行时构建C＃代码。这是我正在研究的一个简单的游戏引擎，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调用我的引擎的“Engine.Print（”Foobar“）;来自脚本DLL的方法）引擎也能够使用脚本的方法（引擎搜索到编译后在脚本中定义的所有新类，并在编译后调用它们的“OnCompile（）”方法。
问题始于脚本间通信：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();
}
}
此代码功能，调试输出打印：
OnCompile库存
OnCompile播放器
玩家创建了
但是，一旦我取消注释inventory = new Inventory（）;在Player构造函数中 调试输出如下：
OnCompile库存
OnCompile Player
未处理的异常：System.Reflection.TargetInvocationException：调用的目标抛出了异常。 ---＆GT; 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。 在Scripts.Player.Player..ctor（） 在Scripts.Player.Player.OnCompile（）
我确保我的Player.cs.dll引用了Inventory.cs.dll。我的编译代码如下：
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;
}
}
我已经完成了代码，Inventory.cs总是按照预期在Player.cs之前编译，并且在编译之前正确地将Inventory.cs.dll添加到Player.cs的引用列表中。
我必须遗漏一些东西，只是链接引用列表中的DLL似乎不够，错误提到找不到Inventory.cs文件。在哪里指定搜索源.cs的路径？ （.cs.dll编译脚本始终与.cs源脚本位于同一路径中）
答案 0 :(得分：1)
您需要为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已使用Assembly.LoadFrom()加载的程序集。
加载Assembly.LoadFrom()的程序集属于所谓的loadfrom context。加载了Assembly.Load()的正常引用的程序集和程序集属于加载上下文。程序集找不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被加载到loadfrom context中，因此它们应该能够彼此相继。但是，执行程序集存在于加载上下文中，因此无法在loadfrom上下文中查看其他程序集。 results.CompiledAssembly.GetTypes()强制将程序集加载到加载上下文中，并抛出异常，因为无法解析程序集引用。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。
有关绑定上下文的更多信息：http://blogs.msdn.com/b/suzcook/archive/2003/05/29/57143.aspx