将C＃结构编排为C ++使用StructureToPtr [英] Marshalling C# structure to C++ Using StructureToPtr

问题描述

我有C＃类：

 命名空间模型
 {
 [StructLayout（LayoutKind.Explicit， size = 120，CharSet = CharSet.Unicode）] 
 public struct DynamicState 
 {
 [FieldOffset（0）] 
 public double [] Position; 
 
 [FieldOffset（24）] 
 public double [] Velocity; 
 
 [FieldOffset（48）] 
 public double []加速; 
 
 [FieldOffset（72）] 
 public double [] Attitude; 
 
 [FieldOffset（96）] 
 public double [] AngularVelocity; 
} 
} 
  

和C ++ / CLI方法：

  Models :: DynamicState SomeClassClr :: DoSomething（Models :: DynamicState ds）
 {
 int struct_size = Marshal :: SizeOf （ds）。 
 System :: IntPtr ptr = Marshal :: AllocHGlobal（struct_size）; 
 DynamicStateStruct ds_struct; 
 struct_size = sizeof（ds_struct）; 
 
 Marshal :: StructureToPtr（ds，ptr，false）; 
 ds_struct = *（DynamicStateStruct *）ptr.ToPointer（）; 
 
 Models :: DynamicState returnVal; 
 mpSomeClass-> doSomething（ds_struct）; 
 
 return returnVal; 
} 
  

其中DynamicStateStruct是本地C ++类：

  struct DynamicStateStruct 
 {
 double mPosition [3]; 
 double mVelocity [3]; 
 double mAcceleration [3]; 
 double mAttitude [3]; 
 double mANGularVelocity [3]; 
}; 
  

当我恢复struct（ ds_struct ）

解决方案

尝试以下变体：

/ p>

  public struct DynamicState 
 {
 [MarshalAs（UnmanagedType.ByValArray，SizeConst = 3）] 
 public double [] Position; 
 
 [MarshalAs（UnmanagedType.ByValArray，SizeConst = 3）] 
 public double [] Velocity; 
 
 [MarshalAs（UnmanagedType.ByValArray，SizeConst = 3）] 
 public double []加速; 
 
 [MarshalAs（UnmanagedType.ByValArray，SizeConst = 3）] 
 public double [] Attitude; 
 
 [MarshalAs（UnmanagedType.ByValArray，SizeConst = 3）] 
 public double [] AngularVelocity; 
} 
  

另一个选择是使用不安全代码中的固定数组：

  public unsafe struct DynamicState 
 {
 public fixed double Position [3]; 
 
 public fixed double Velocity [3]; 
 
 public fixed double Acceleration [3]; 
 
 public fixed double Attitude [3]; 
 
 public fixed double AngularVelocity [3]; 
} 
  

有关.Net互操作的好指南，请点击此处： http://www.mono-project.com/Interop_with_Native_Libraries

I have C# class:

namespace Models
{
    [StructLayout(LayoutKind.Explicit, Size = 120, CharSet = CharSet.Unicode)]
    public struct DynamicState
    {
        [FieldOffset(0)]
        public double[] Position;

        [FieldOffset(24)]
        public double[] Velocity;

        [FieldOffset(48)]
        public double[] Acceleration;

        [FieldOffset(72)]
        public double[] Attitude;

        [FieldOffset(96)]
        public double[] AngularVelocity;
    }
}

and C++/CLI method:

Models::DynamicState SomeClassClr::DoSomething(Models::DynamicState ds)
{
    int struct_size = Marshal::SizeOf(ds);
    System::IntPtr ptr = Marshal::AllocHGlobal(struct_size);
    DynamicStateStruct ds_struct;
    struct_size = sizeof(ds_struct);

    Marshal::StructureToPtr(ds, ptr, false);
    ds_struct = *(DynamicStateStruct*)ptr.ToPointer();

    Models::DynamicState returnVal;
    mpSomeClass->doSomething(ds_struct);

    return returnVal;
}

where DynamicStateStruct is a native C++ class:

struct DynamicStateStruct
{
    double mPosition[3];
    double mVelocity[3];
    double mAcceleration[3];
    double mAttitude[3];
    double mAngularVelocity[3];
};

When I recover the struct (ds_struct) in native C++ I am not getting the correct values, any ideas with what I am missing?

解决方案

Try the following variant:

public struct DynamicState
{
    [MarshalAs (UnmanagedType.ByValArray, SizeConst=3)]
    public double[] Position;

    [MarshalAs (UnmanagedType.ByValArray, SizeConst=3)]
    public double[] Velocity;

    [MarshalAs (UnmanagedType.ByValArray, SizeConst=3)]
    public double[] Acceleration;

    [MarshalAs (UnmanagedType.ByValArray, SizeConst=3)]
    public double[] Attitude;

    [MarshalAs (UnmanagedType.ByValArray, SizeConst=3)]
    public double[] AngularVelocity;
}

Another option is to use fixed array available in unsafe code:

public unsafe struct DynamicState
{
    public fixed double Position[3];

    public fixed double Velocity[3];

    public fixed double Acceleration[3];

    public fixed double Attitude[3];

    public fixed double AngularVelocity[3];
}

P.S. A good guide on .Net interop can be found here: http://www.mono-project.com/Interop_with_Native_Libraries

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