在C＃中使用数组和指针与C DLL [英] Using arrays and pointers in C# with C DLL

问题描述

我很新的C＃（刚开始在过去一周的学习）。

I am very new to C# (just started learning in the past week).

我已经写在C具有以下功能的自定义DLL：

I have a custom DLL written in C with the following function:

DLLIMPORT void test_function (double **test)

我所希望做的是必须从C＃为阵测试。

What I am looking to do is have a pointer from C# for the array 'test'.

所以，如果在DLL函数我有测试[0] = 450.60，测试[1] = 512.99等等。我希望能有一个可在我的C＃程序。

So, if in the DLL function I have test[0] = 450.60, test[1] = 512.99 etc. I want to be able to have that available in my C# program.

在C＃程序我有类似的东西：

In the C# program I have something similar to:

namespace TestUtil
{
  public class Echo
  {
    public double[] results = new double[10];
    public double[] results_cpy = new double[10];


    [DllImport("test_dll.dll", CallingConvention = CallingConvention.Cdecl)]
    static extern unsafe void test_function(ref double[] Result);

    public unsafe void Tell()
    {
      results[0] = 0.0;
      results[1] = 0.0;

      results_cpy[0] = 0.0;
      results_cpy[1] = 0.0;

      test_function(ref results);
      results_cpy[0] = (double)results[0] + (double)results[1] ;
    }
  }
}

在DLL的test_function功能我用下面的：

In the DLL's 'test_function' function I used the following:

*test[0] = 450.60;
*test[1] = 512.99;

在DLL一切都OK（我用一个消息框在DLL中被应用到检查值）。早在C＃程序的结果[0]'似乎都很正常，我可以从中获得价值，但'结果[1]给我一个索引越界的错误。我知道这是因为，如果我省略'+（双）结果[1]我收到任何错误。另外，如果我做的DLL中没有试图修改测试[1]它保留从C＃原始值（在我的例子0.0）。

Within the DLL everything was OK (I used a message box within the DLL to check the values were being applied). Back in the C# program 'results[0]' appears to be fine and I can get values from it, but 'results[1]' gives me an index out of bounds error. I know this because if I omit '+ (double)results[1]' I receive no error. Also, if I make no attempt within the DLL to modify 'test[1]' it retains the original value from C# (in my example 0.0).

显然，我没有做正确的事情，但这是我已经能够去拥有它在所有的工作最接近的一次。别的我已经试过各种悲惨的失败了。

Obviously I am not doing something right but this is the closest I have been able to get to having it work at all. Everything else I have tried fails miserably.

任何帮助将大大AP preciated。

Any help would be greatly appreciated.

推荐答案

有没有需要不安全code。其实，没有必要通过引用都传递。如果你的签名是这样的：

There's no need for unsafe code. In fact, there's no need to pass by reference at all. If your signature looks like this:

void test_function (double *test)

和导入是这样的：

static extern void test_function(double[] Result);

然后一切都应该正常工作。也就是说，假设你只需要修改阵列并不会返回一个完全新的数组。

Then everything should work fine. That is, assuming you only need to modify the array and not return a completely new array.

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