从C ++到C#整理数组的数组 [英] Marshalling an array of arrays from C++ to C#

问题描述

好的，我已经从一些C ++代码回调到了一些C#代码，以处理数据数组和数据结构.

在C ++中，回调声明为:

ok, i''ve got a callback from some C++ code to some C# code to handle an array of data, and a data structure.

In C++ the callback is declared as:

int MyCallBack(const MyStruct* pMyStruct,  // pointer to a struct
               unsigned short* pMyData,    // array of ushorts
               unsigned int nMyDataLength, // length of the previous array
               void* pInfo);               // some extra data (not relevant to the question)

我声明委托以如下方式在C#中处理此问题:

I declare the delegate to handle this in C# as follows:

public delegate int MyCallBack(
    ref MyStruct myStruct,
    [MarshalAs(UnmanagedType.LPArray,   SizeParamIndex = 2)] ushort[] myData,
    uint myDataLength,
    IntPtr userInfoStruct);

到目前为止一切正常.
但是，现在我想在一次调用中将多个数据数组传递回C#，以避免某些本机管理的开销

我在C ++中对多个回调的声明如下:

This all works fine so far.
However now i want to pass multiple arrays of data back to the C# in a single call to avoid some of the native->managed overhead

My declaration in C++ for the multiple callbacks is as follows:

int MyCallBack2(const MyStruct* pMyStruct,          // array of structs
                unsigned short** pMyDataArray,      // array of ushort arrays
                unsigned int* nMyDataLengthArray,   // array of lengths 
                              // corresponding to each of the ushort arrays
                unsigned int dataCount,             // the count of elements in 
                                                    // the arrays above
                void* pInfo);                       // some extra data (not relevant to the question)

我在弄清楚C#中此回调的委托声明时遇到了一些麻烦

这是我到目前为止所得到的:

I''m having some trouble figuring out the declaration for the delegate for this callback in the C#

This is what I''ve got so far:

public delegate int MyCallBack2(
    [MarshalAs(UnmanagedType.LPArray, SizeParamIndex=3)] MyStruct[] myStructArray,
    [MarshalAs(UnmanagedType.LPArray, SizeParamIndex=3)] IntPtr[] myDataArray,
    [MarshalAs(UnmanagedType.LPArray, SizeParamIndex=3)] int[] myDataLengthArray,
    uint myDataCount,
    IntPtr userInfoStruct);

谁能告诉我如何从上述myDataArray中的IntPtrs中获取每个ushort []数组?

谢谢，
Pete

Can anyone tell me how I get each of the ushort[] arrays from the IntPtrs in myDataArray above?

Thanks,
Pete

推荐答案

好，
我似乎有解决办法.
对上面的MyCallBack2使用声明:

Ok,
I seem to have a solution.
Using the declaration for MyCallBack2 above:

public ushort ShortToUShort(short val)
{
    return (ushort)val;
}
public int MyCallBack2(MyStruct[] myStructArray,
                       IntPtr[] myDataArray,
                       uint[] myDataLengthArray,
                       uint myDataCount,
                       IntPtr userInfoStruct)
{
    for (int i = 0; i < myDataCount; ++i)
    {
        short[] tmpMyData = new short[myDataLengthArray[i]];
        Marshal.Copy(myStructArray[i], tmpMyData, 0, (int)myDataLengthArray[i]);
        ushort[] myData = Array.ConvertAll<short, ushort>(tmpMyData,
                                                          new Converter<short, ushort>(ShortToUShort));
        MyCallBack(ref myStructArray[i],
                   myData,
                   myDataLengthArray[i],
                   userInfoStruct);
    }
    return 1;
}

这似乎可以运行，但是将short []转换为ushort []看起来很混乱，必须有一种更干净的方法来实现.

同样，当我在调试器中运行此程序时，Visual Studio在停止调试时也会挂在我身上.

This appears to run ok, however it looks messy converting the short[] to a ushort[], there has to be a cleaner way to do this.

Also when i run this in the debugger, Visual Studio hangs on me when I stop debugging.

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