在C#中，如何将struct转为IntPtr？

Question

要把一个C#的struct传递给C++写的dll，如何才能在C#中获得这个struct的IntPtr指针？

Answer 1

如果有结构类型的参数，你只需定义似于的结构不就好了?
如：
 [StructLayout(LayoutKind.Sequential)]                                 
 public  struct    RECT                                                     {                                   
   public Int16  test....
}
应该没必要struct转为IntPtr吧.

Answer 2

C++跟C#不一样反正 
c#中这样定义 
struct b 
{ 
  IntPtr sp； 
} 然后在 
str_a  ss=new str_a(); 
IntPtr sp = Marshal.AllocCoTaskMem(Marshal.SizeOf(ss)); 
Marshal.StructureToPtr(ss, sp, false); 

Answer 3

dll函数如下：
[DllImport("Coredll.dll", CharSet = CharSet.Auto, EntryPoint = "VirtualAlloc")]
public static extern IntPtr VirtualAlloc(
IntPtr lpAddress,
uint dwSize,
uint flAllocationType,
uint flProtect);lpAddress需要传入结构体的指针，在C#中定义如下。随便问一下，IOPreg中有一个2个值的数组，C#中的数组初始化真是复杂，而且我对这个数组初始化了，struct中的其它元素也要初始化才能编译通过，有没有简单的方法。
public struct IOPreg{
        public uint rGPACON; // 00
        public uint rGPADAT;
        public uint[] rPAD1;        public uint rGPBCON; // 10
        public uint rGPBDAT;
        public uint rGPBUP;
        public uint rPAD2;        public uint rGPCCON; // 20
        public uint rGPCDAT;
        public uint rGPCUP;
        public uint rPAD3;        public uint rGPDCON; // 30
        public uint rGPDDAT;
        public uint rGPDUP;
        public uint rPAD4;        public uint rGPECON; // 40
        public uint rGPEDAT;
        public uint rGPEUP;
        public uint rPAD5;        public uint rGPFCON; // 50
        public uint rGPFDAT;
        public uint rGPFUP;
        public uint rPAD6;        public uint rGPGCON; // 60
        public uint rGPGDAT;
        public uint rGPGUP;
        public uint rPAD7;        public uint rGPHCON; // 70
        public uint rGPHDAT;
        public uint rGPHUP;
        public uint rPAD8;        public uint rMISCCR; // 80
        public uint rDCKCON;
        public uint rEXTINT0;
        public uint rEXTINT1;
        public uint rEXTINT2; // 90
        public uint rEINTFLT0;
        public uint rEINTFLT1;
        public uint rEINTFLT2;
        public uint rEINTFLT3; // A0
        public uint rEINTMASK;
        public uint rEINTPEND;
        public uint rGSTATUS0; // AC
        public uint rGSTATUS1; // B0
        public uint rGSTATUS2; // B4
        public uint rGSTATUS3; // B8
        public uint rGSTATUS4; // BC
        public IOPreg(uint i)
        {
              
        rGPACON=0; // 00
         rGPADAT=0;
         rPAD1 = new uint[2];         rGPBCON=0; // 10
         rGPBDAT=0;
         rGPBUP=0;
         rPAD2=0;         rGPCCON=0; // 20
         rGPCDAT=0;
         rGPCUP=0;
         rPAD3=0;         rGPDCON=0; // 30
         rGPDDAT=0;
         rGPDUP=0;
         rPAD4=0;         rGPECON=0; // 40
         rGPEDAT=0;
         rGPEUP=0;
         rPAD5=0;         rGPFCON=0; // 50
         rGPFDAT=0;
         rGPFUP=0;
         rPAD6=0;         rGPGCON=0; // 60
         rGPGDAT=0;
         rGPGUP=0;
         rPAD7=0;         rGPHCON=0; // 70
         rGPHDAT=0;
         rGPHUP=0;
         rPAD8=0;         rMISCCR=0; // 80
         rDCKCON=0;
         rEXTINT0=0;
         rEXTINT1=0;
         rEXTINT2=0; // 90
         rEINTFLT0=0;
         rEINTFLT1=0;
         rEINTFLT2=0;
         rEINTFLT3=0; // A0
         rEINTMASK=0;
         rEINTPEND=0;
         rGSTATUS0=0; // AC
         rGSTATUS1=0; // B0
         rGSTATUS2=0; // B4
         rGSTATUS3=0; // B8
         rGSTATUS4=0; // BC
      }

Answer 4

如果有结构类型的参数，你只需定义似于的结构不就好了? 
如： 
[StructLayout(LayoutKind.Sequential)]                                
public  struct    RECT                                                    {                                  
  public Int16  test.... 
} 
应该没必要struct转为IntPtr

Answer 5

 public struct A
        {
            public int X;
            public int Y;
        }        private void button1_Click(object sender, EventArgs e)
        {
            A Test =new A();
            Test.X=100;
            Test.Y=100;
            int _StructSize =System.Runtime.InteropServices.Marshal.SizeOf(Test);            IntPtr _StuctIntPtr = System.Runtime.InteropServices.Marshal.AllocCoTaskMem(_StructSize);            System.Runtime.InteropServices.Marshal.StructureToPtr(Test, _StuctIntPtr, true);            byte[] _Temp = new byte[8];            System.Runtime.InteropServices.Marshal.Copy(_StuctIntPtr, _Temp, 0, 8);        }
看看这样可以不

Answer 6

实例个struct    然后使用ref 不就可以了.关键是C# 的STRUCT 跟C++ 里面的结构一样。

Answer 7

以下是MSDN的示例，创建一个托管结构，使用 StructureToPtr 方法将它传输到非托管内存，然后使用 PtrToStructure 方法将它传输回托管内存中：
using System;
using System.Runtime.InteropServices;public struct Point
{
    public int x;
    public int y;
}class Example
{
    static void Main()
    {
        // Create a point struct.
        Point p;
        p.x = 1;
        p.y = 1;        Console.WriteLine("The value of first point is " + p.x + " and " + p.y + ".");        // Initialize unmanged memory to hold the struct.
        IntPtr pnt = Marshal.AllocHGlobal(Marshal.SizeOf(p));        try
        {
            // Copy the struct to unmanaged memory.
            Marshal.StructureToPtr(p, pnt, false);            // Create another point.
            Point anotherP;            // Set this Point to the value of the 
            // Point in unmanaged memory. 
            anotherP = (Point)Marshal.PtrToStructure(pnt, typeof(Point));            Console.WriteLine("The value of new point is " + anotherP.x + " and " + anotherP.y + ".");        }
        finally
        {
            // Free the unmanaged memory.
            Marshal.FreeHGlobal(pnt);
        }
    }
}

Answer 8

个人习惯直接传结构，使用ref

Answer 9

5楼正解！！！有时候C++的参数中有void *, 而且调用的时候传不同的结构体指针