C#调用C++ 平台调用P/Invoke 结构体--结构体嵌套【八】

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普通的结构体嵌套很简单，C#中直接定义成对应的结构体即可，这里介绍的是嵌套的结构体以指针的方式表达

【1】嵌套结构体指针

C++代码：

typedef struct _testStru10Pre
{ 
  int  iVal;
}testStru10Pre;
typedef struct _testStru10
{ 
  testStru10Pre *pPre;
  long      lVal;
  _testStru10()
  {
    pPre = NULL;
  }
}testStru10;

EXPORTDLL_API void Struct_NestStruct( testStru10 *pStru )
{
  if (NULL == pStru)
  {
    return;
  }

  pStru->lVal = 10;
  if (NULL != pStru->pPre)
  {
    pStru->pPre->iVal = 9;
  }

  wprintf(L"Struct_NestStruct \n");
}

C#代码：定义为IntPtr需要进行解析：

public struct testStru10Pre
{
    public int iVal;
};
public struct testStru10
{
    public IntPtr pPre;
    public int lVal;
};
[DllImport("ExportDll.dll", CharSet = CharSet.Unicode)]
public static extern void Struct_NestStruct(ref testStru10 pStru);

测试：

CExportDll.testStru10Pre str10Pre = new CExportDll.testStru10Pre();
IntPtr intPtrStru10Pre = Marshal.AllocCoTaskMem(Marshal.SizeOf(str10Pre));
Marshal.StructureToPtr(str10Pre, intPtrStru10Pre, false);

CExportDll.testStru10 stru10 = new CExportDll.testStru10();
stru10.pPre = intPtrStru10Pre;
CExportDll.Struct_NestStruct(ref stru10);
CExportDll.testStru10Pre str10Pre2 = (CExportDll.testStru10Pre)Marshal.PtrToStructure(stru10.pPre, typeof(CExportDll.testStru10Pre));

Marshal.DestroyStructure(intPtrStru10Pre, typeof(CExportDll.testStru10Pre));