加载DLL的多个实例（C＃/。NET） [英] Loading multiple instance of DLL (C#/.NET)

问题描述

我正在开发C＃/ .NET 3.5应用程序。我正在使用C中的legacy DLL，signals.dll。我使用P / Invoke从.NET包装器调用它。我正在调用2种类型的处理函数，类型为A和B.当我只调用一种类型的处理时，一切正常。当我将电话交给A和B处理时，数据结果被破坏。我相信dll，signals.dll正在使用C风格的全局变量，数据被破坏。

为了解决这个问题，我在磁盘上创建了2个副本的信号。 dll和signals2.dll然后我使用P / Invoke修改.NET包装器，将类型A处理直接引导到一个dll，将B处理类型转换为另一个实例。现在，所有的工作都很好。

然后我在论坛和解决方案上看到类似的问题。 （支持具有全局数据的插件DLL的多个实例）。
基本上，提出的解决方案是从代码中动态的，在磁盘上创建一个.dll的新实例（根据需要），并加载它并从中调用函数。代码的关键部分如下所示：

  private IntPtr dllHandle; 
 string myDllPath = Path.Combine（dllDir，String.Format（mylib- {0} .dll，GetHashCode（）））; 
 File.Copy（origDllPath，myDllPath）; 
 dllPath = myDllPath; 
 dllHandle = LoadLibrary（dllPath）; 
 _getVersion = GetProcEntryDelegate< _getVersionDelegate>（dllHandle，GetVersion）; 
 
 private delegate int _getVersionDelegate（）; 
 private readonly _getVersionDelegate _getVersion; 
 
 public int GetVersion（）
 {
 return _getVersion（）; 
} 
 
私有静态D GetProcEntryDelegate< D>（IntPtr hModule，字符串名称）
其中D：class 
 {
 IntPtr addr = _getProcAddress（hModule ， 名称）; 
 if（addr == IntPtr.Zero）
 throw new Win32Exception（）; 
返回Marshal.GetDelegateForFunctionPointer（addr，typeof（D））作为D; 
} 
  

我想到了什么，是否可以修改上述代码创建dll IN MEMORY的副本，而不是在磁盘上加载它。我认为只有IntPtr dllHandle需要被愚弄从内存获取价值，而不是从LoadLibrary获取价值。怎么做？

解决方案

没有什么只是关于它:) - 复杂和涉及

这是一个可能有帮助的链接 - 从内存中加载库/模块

而且，由于@Hans Passant表示我会阻止您这样做 - 即使可能对于某些场景，这是一个诱人的解决方案（但是我并不认为你真的需要诚实，很可能）。

它涉及处理便携式可执行格式 - 我怀疑该项目涵盖了所有需要完成的工作。

您可以尝试使用C ++ / CLI包装器 - 或导出 MemoryLoadLibrary 并尝试P /调用 - 但是怀疑这个工作很容易。

I am developing C#/.NET 3.5 application. I am using legacy dll written in C, signals.dll. I invoke it from a .NET wrapper using P/Invoke. I am calling 2 types of processing functions, type A and B. When I call only one type of processing, all works fine. When I interleave calls to A and B processing, data result is corrupted. I believe that dll, signals.dll is using C style global variables, and data gets corrupted.

To resolve that, I created 2 copies of dll on disk, signals.dll and signals2.dll. Then I modified .NET wrapper using P/Invoke to direct type A processing to one dll, type B processing to another instance. And now, all works fine.

Then I saw similar problem on forums and solution there. (Supporting multiple instances of a plugin DLL with global data ). Basically, that proposed solution is dynamic lay from code, creating a new instance of .dll on disk (based on need), and loads it and invokes functions from it. Key part of code looks like this:

private IntPtr dllHandle;
string myDllPath = Path.Combine(dllDir, String.Format("mylib-{0}.dll", GetHashCode()));
        File.Copy(origDllPath, myDllPath);
        dllPath = myDllPath;
        dllHandle = LoadLibrary(dllPath);
        _getVersion = GetProcEntryDelegate<_getVersionDelegate>(dllHandle, "GetVersion");

    private delegate int _getVersionDelegate();
    private readonly _getVersionDelegate _getVersion;

public int GetVersion()
    {
        return _getVersion();
    }

private static D GetProcEntryDelegate<D>(IntPtr hModule, string name)
        where D: class
    {
        IntPtr addr = _getProcAddress(hModule, name);
        if (addr == IntPtr.Zero)
            throw new Win32Exception();
        return Marshal.GetDelegateForFunctionPointer(addr, typeof(D)) as D;
    }

What is coming to my mind, would it be possible to modify above code to create copy of dll IN MEMORY, not on disk and load it from there. I think just that IntPtr dllHandle needs to be fooled into getting value from memory, not from LoadLibrary. How to do that?

解决方案

There is nothing just about it :) - it's far more complex and involving

Here is a link that might help - Load Library/Module from Memory

And as @Hans Passant said I'd discourage you to go that way - even though it may be a tempting solution for some scenarios (but I don't see that you really need that honestly, nice maybe).

It involves dealing with the portable executable format - and I doubt that project covers all that needs to be done.

You could try making your C++/CLI wrapper - or exporting the MemoryLoadLibrary and try P/Invoking - but I doubt that'd work easily.

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