在C#中使用外部C声明 [英] Using External C declarations in C#

问题描述

我对要在C#应用程序中调用的dll中的函数有一个外部声明.

声明的形式为

I have an external declaration for a function in a dll I wish to call in a C# application.

The declaration is in the form

extern int WINAPI PassBuffer(void *lpDib);

其中* lpDib表示要传递给dll的位图或Dib.我在dll的".h"文件中找到了此文件.

我不确定实际发生了什么，但我认为lpDib是我要传递的bmp的指针.

我在C#应用程序中将函数声明为:

where *lpDib refers to a bitmap or Dib to be passed to the dll. This I found in a ''.h'' file for the dll.

I''m not certain whats actually happening but I assume, lpDib is a pointer to the bmp I want to pass.

I''ve declared the function in my C# application as:

private static extern int PassBuffer(IntPtr lpDib);

首先，这是正确的吗?其次如何获取指向我的bmp的指针.

其声明:

Firstly, is this correct? and secondly how do i get the pointer to my bmp.

Its declared:

Bitmap bmp = new Bitmap("c:\\My.JPG");

如何获取bmp的指针以

How do I get the pointer of the bmp to hand to

PassBuffer(whatgoeshere);

谢谢您的帮助，我知道这将是一个愚蠢的问题，答案很简单，但让我感到困惑...

Thanks for any help, I know its going to be a dumb question with a simple answer but its got me stumped...

推荐答案

尝试使用此方法:

Try using this:

// Create a new bitmap.
Bitmap bmp = new Bitmap("c:\\my.jpg");

// Lock the bitmap's bits.
Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
System.Drawing.Imaging.BitmapData bmpData =
    bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,
    bmp.PixelFormat);

// Get the address of the first line.
IntPtr ptr = bmpData.Scan0;

然后在PassBuffer中使用ptr.

Then use the ptr in PassBuffer.

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