用Visual C#调用Windows API函数

[DllImport("User32.dll")]

public static extern Bool PtInRect(ref Rect r, Point p);

}

类似你可以调用GetSystemInfo函数获得系统信息：

? using System.Runtime.InteropServices;

[StructLayout(LayoutKind.Sequential)]

public struct SYSTEM_INFO {

public uint dwOemId;

public uint dwPageSize;

public uint lpMinimumApplicationAddress;

public uint lpMaximumApplicationAddress;

public uint dwActiveProcessorMask;

public uint dwNumberOfProcessors;

public uint dwProcessorType;

public uint dwAllocationGranularity;

public uint dwProcessorLevel;

public uint dwProcessorRevision;

}

[DllImport("kernel32")]

static extern void GetSystemInfo(ref SYSTEM_INFO pSI);

SYSTEM_INFO pSI = new SYSTEM_INFO();

GetSystemInfo(ref pSI);

同样只要类具有一个固定的类成员布局，你也可以传递一个类成员给一个不受管辖的动态链接库函数，下面的例子主要说明如何传递一个sequential顺序定义的MySystemTime类给User32.dll的GetSystemTime函数, 函数用C/C++调用规范如下:

void GetSystemTime(SYSTEMTIME* SystemTime);

不像传值类型,类总是通过引用传递参数.

[C#]

[StructLayout(LayoutKind.Sequential)]

public class MySystemTime {

public ushort wYear;

public ushort wMonth;

public ushort wDayOfWeek;

public ushort wDay;

public ushort wHour;

public ushort wMinute;

public ushort wSecond;

public ushort wMilliseconds;

}

class Win32API {