Minesweeper, Behind the scenes

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace ProcessMemoryReaderLib
{
	/// <summary>
	/// ProcessMemoryReader is a class that enables direct reading a process memory
	/// </summary>
	class ProcessMemoryReaderApi
	{
		// constants information can be found in <winnt.h>
		public const uint PROCESS_VM_READ = (0x0010);
		
		// function declarations are found in the MSDN and in <winbase.h> 
		
		//		HANDLE OpenProcess(
		//			DWORD dwDesiredAccess,  // access flag
		//			BOOL bInheritHandle,    // handle inheritance option
		//			DWORD dwProcessId       // process identifier
		//			);
		[DllImport("kernel32.dll")]
		public static extern IntPtr OpenProcess(UInt32 dwDesiredAccess, Int32 bInheritHandle, UInt32 dwProcessId);

		//		BOOL CloseHandle(
		//			HANDLE hObject   // handle to object
		//			);
		[DllImport("kernel32.dll")]
		public static extern Int32 CloseHandle(IntPtr hObject);

		//		BOOL ReadProcessMemory(
		//			HANDLE hProcess,              // handle to the process
		//			LPCVOID lpBaseAddress,        // base of memory area
		//			LPVOID lpBuffer,              // data buffer
		//			SIZE_T nSize,                 // number of bytes to read
		//			SIZE_T * lpNumberOfBytesRead  // number of bytes read
		//			);
		[DllImport("kernel32.dll")]
		public static extern Int32 ReadProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress,[In, Out] byte[] buffer, UInt32 size, out IntPtr lpNumberOfBytesRead);
	}

	public class ProcessMemoryReader
	{

		public ProcessMemoryReader()
		{
		}

        /// <summary>	
		/// Process from which to read		
		/// </summary>
		public Process ReadProcess
		{
			get
			{
				return m_ReadProcess;
			}
			set
			{
				m_ReadProcess = value;
			}
		}

		private Process m_ReadProcess = null;

		private IntPtr m_hProcess = IntPtr.Zero;

		public void OpenProcess()
		{
			m_hProcess = ProcessMemoryReaderApi.OpenProcess(ProcessMemoryReaderApi.PROCESS_VM_READ, 1, (uint)m_ReadProcess.Id);
		}

		public void CloseHandle()
		{
			int iRetValue;
			iRetValue = ProcessMemoryReaderApi.CloseHandle(m_hProcess);
			if (iRetValue == 0)
				throw new Exception("CloseHandle failed");
		}

		public byte[] ReadProcessMemory(IntPtr MemoryAddress, uint bytesToRead, out int bytesReaded)
		{
			byte[] buffer = new byte[bytesToRead];
			
			IntPtr ptrBytesReaded;
			ProcessMemoryReaderApi.ReadProcessMemory(m_hProcess,MemoryAddress,buffer ,bytesToRead,out ptrBytesReaded);
			
			bytesReaded = ptrBytesReaded.ToInt32();

			return buffer;
		}
	}
}