请教C#调用C++ dll时一个难导入的函数

Question

请教大家如何在C#中导入如下的函数，这个函数在c++写的dll中：
extern __declspec(dllimport) BOOL WINAPI GetOutputBMPdata(UCHAR const **  pData, BITMAPINFO const ** pInfo);如果用c#调用DllImport应该怎么写？主要是类型要正确，UCHAR对应byte但是不知道UCHAR const **这个二维的图像数据矩阵要怎么转换，还有是不是要在C#里把BITMAPINFO也重构出来啊，这个应该不是很必要，毕竟C#有Bitmap和BitmapData可以用。请求大家的帮助，谢谢 

Answer 1

这个函数功能是获取输出的256色位图数据，用于在View中绘图的
如下：
const UCHAR * pBmpData=NULL, * pColorBarData=NULL;
const BITMAPINFO * pBmpInfo=NULL, * pColoarBarInfo=NULL;

if ( !MAG_GetOutputBMPdata(&pBmpData, &pBmpInfo) ||
!MAG_GetOutputColorBardata(&pColorBarData, &pColoarBarInfo))
{
MAG_UnLockFrame();
MemDC.SelectObject(pOldBit);
MemBitmap.DeleteObject();
MemDC.DeleteDC();
return;
}StretchDIBits(MemDC.GetSafeHdc(), 5, 5, BMPWIDTH, BMPHEIGHT, 
0, 0, BMPWIDTH, BMPHEIGHT, 
pBmpData, pBmpInfo,
DIB_RGB_COLORS, SRCCOPY);

Answer 2

http://blog.csdn.net/lifeilin6671/article/details/8287271
难道是用ref byte[] ?

Answer 3

/// <summary>
/// 封送C++中的BITMAPINFOHEADER结构。
/// </summary>
[StructLayout(LayoutKind.Sequential)]
public struct BitmapInfoHeader
{
    [MarshalAs(UnmanagedType.I4)]
    public Int32 biSize;
    [MarshalAs(UnmanagedType.I4)]
    public Int32 biWidth;
    [MarshalAs(UnmanagedType.I4)]
    public Int32 biHeight;
    [MarshalAs(UnmanagedType.I2)]
    public short biPlanes;
    [MarshalAs(UnmanagedType.I2)]
    public short biBitCount;
    [MarshalAs(UnmanagedType.I4)]
    public Int32 biCompression;
    [MarshalAs(UnmanagedType.I4)]
    public Int32 biSizeImage;
    [MarshalAs(UnmanagedType.I4)]
    public Int32 biXPelsPerMeter;
    [MarshalAs(UnmanagedType.I4)]
    public Int32 biYPelsPerMeter;
    [MarshalAs(UnmanagedType.I4)]
    public Int32 biClrUsed;
    [MarshalAs(UnmanagedType.I4)]
    public Int32 biClrImportant;
}/// <summary>
/// 封送C++中的BITMAPINFO结构。
/// </summary>
[StructLayout(LayoutKind.Sequential)]
public struct BitmapInfo
{
    [MarshalAs(UnmanagedType.Struct, SizeConst = 40)]
    public BitmapInfoHeader bmiHeader;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 1024)]
    public Int32[] bmiColors;
}

Answer 4

[StructLayoutAttribute(LayoutKind.Sequential)]
public struct BITMAPINFO
{
    /// BITMAPINFOHEADER->tagBITMAPINFOHEADER
    public BITMAPINFOHEADER bmiHeader;    /// RGBQUAD[1]
    [MarshalAsAttribute(UnmanagedType.ByValArray, SizeConst = 1, ArraySubType = UnmanagedType.Struct)]
    public RGBQUAD[] bmiColors;
}[StructLayoutAttribute(LayoutKind.Sequential)]
public struct BITMAPINFOHEADER
{
    /// DWORD->unsigned int
    public uint biSize;    /// LONG->int
    public int biWidth;    /// LONG->int
    public int biHeight;    /// WORD->unsigned short
    public ushort biPlanes;    /// WORD->unsigned short
    public ushort biBitCount;    /// DWORD->unsigned int
    public uint biCompression;    /// DWORD->unsigned int
    public uint biSizeImage;    /// LONG->int
    public int biXPelsPerMeter;    /// LONG->int
    public int biYPelsPerMeter;    /// DWORD->unsigned int
    public uint biClrUsed;    /// DWORD->unsigned int
    public uint biClrImportant;
}[StructLayoutAttribute(LayoutKind.Sequential)]
public struct RGBQUAD
{
    /// BYTE->unsigned char
    public byte rgbBlue;    /// BYTE->unsigned char
    public byte rgbGreen;    /// BYTE->unsigned char
    public byte rgbRed;    /// BYTE->unsigned char
    public byte rgbReserved;
}public partial class NativeMethods
{    /// Return Type: BOOL->int
    ///pData: UCHAR**
    ///pInfo: BITMAPINFO**
    [DllImportAttribute("<Unknown>", EntryPoint = "MAG_GetOutputColorBardata")]
    [return: MarshalAsAttribute(UnmanagedType.Bool)]
    public static extern bool MAG_GetOutputColorBardata(ref IntPtr pData, ref IntPtr pInfo);}不是找到P/Invoke Interop Assistant 今晚真成了我的世界末日了。
结贴