快閃人生: Programming

顯示具有 Programming 標籤的文章。顯示所有文章

2015/3/18

解決呼叫某些系統函數發生'無法解析的外部符號'問題的兩種方法

Windows有些系統函數被存放在像是Shlwapi.lib函數庫中而非常用到的kernel32.lib，在Visual Studio編譯環境中，Linker預設是不會去找Shlwapi.lib等較不常用的Library進行鏈結，所以當呼叫到如PathFileExists等系統函數，編譯過程中就會收到類似錯誤：

1>Source.obj : error LNK2001: 無法解析的外部符號 __imp__PathFileExistsA@4
1>E:\Tmp\ConsoleApplication13\Release\ConsoleApplication13.exe : fatal error LNK1120: 1 個無法解析的外部符號
1>
1>建置失敗。

解決方法有兩種：
其一是透過設定專案屬性→連結器→輸入→其他相依性，加入*.lib（如Shlwapi.lib）

其二是透過假指令#pragma告知編譯環境將調用到*.lib

#pragma comment(lib, "Shlwapi.lib")

2014/8/6

【C#】設定/查詢螢幕背光

　　為了要能用C#控制螢幕背光，跟CreateFile與DeviceIoControl函數奮戰大半天，一直搞不定DeviceIoControl函數使用，後來幸運的在網路上找到有人寫好class可以直接調用，之後有需要用到DeviceIoControl函數功能也能參考這class的做法。

調用方法很簡單：

1
2
3

LCDBrightness lcd = new LCDBrightness();
lcd.SetBrightness(100);                                 // Set backlight full on
LCDBrightness.Brightness value = lcd.GetBrightness();   // Query backlight value

原始class內容為：

using Microsoft.VisualBasic;
using System;
using System.Collections;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;
/// <summary>
/// Permet de contrA’ler la luminositAc de l'Accran LCD (sous Windows XP SP2 et ultAcrieur)
/// </summary>
/// <remarks>Sous rAcserve que le driver de la carte graphique et/ou de l'Accran supporte cette interface</remarks>
namespace LCDBrightness
{
  public class LCDBrightness
  {
    //Ouvre un fichier ou un pAcriphAcrique
    [DllImport("kernel32")]
    private static extern IntPtr CreateFile (
        string lpFileName,
        uint dwDesiredAccess,
        int dwShareMode,
        IntPtr lpSecurityAttributes,
        int dwCreationDisposition,
        int dwFlagsAndAttributes,
        IntPtr hTemplateFile);

    //accA‥s en lecture, partagAc et ouverture uniquement d'un pAcriphAcrique existant
    private const uint GENERIC_READ = 0x80000000U;
    private const int SHARE_ALL = 0x7;
    private const int OPEN_EXISTING = 0x3;

    //indique l'Acclairage en mode d'alimentation AC ou DC ou les deux
    private const int DISPLAYPOLICY_AC = 1;
    private const int DISPLAYPOLICY_DC = 2;
    private const int DISPLAYPOLICY_BOTH = DISPLAYPOLICY_AC | DISPLAYPOLICY_DC;

    /// <summary>
    /// Indique les niveaux d'Acclairage en fonction du mode d'alimentation
    /// </summary>
    /// <remarks></remarks>
    public class Brightness
    {
      /// <summary>
      /// Eclairage en mode Alimentation
      /// </summary>
      /// <remarks></remarks>
      public byte AC;
      /// <summary>
      /// Eclairage en mode Batterie
      /// </summary>
      /// <remarks></remarks>
      public byte DC;
    }

    /// <summary>
    /// Contient les donnAces brutes des niveaux d'Acclairage
    /// </summary>
    /// <remarks></remarks>
    private struct DISPLAY_BRIGHTNESS
    {
      public byte ucDisplayPolicy;
      public byte ucACBrightness;
      public byte ucDCBrightness;
    }

    //envoie une requAate A  un pAcriphAcrique
    [DllImport("kernel32")]
    private static extern bool DeviceIoControl (
        IntPtr hDevice,
        int dwIoControlCode,
        ref DISPLAY_BRIGHTNESS lpInBuffer,
        int nInBufferSize,
        IntPtr lpOutBuffer,
        int nOutBufferSize,
        ref int lpBytesReturned,
        IntPtr lpOverlapped);
    [DllImport("kernel32")]
    private static extern bool DeviceIoControl (
        IntPtr hDevice,
        int dwIoControlCode,
        IntPtr lpInBuffer,
        int nInBufferSize,
        ref DISPLAY_BRIGHTNESS lpOutBuffer,
        int nOutBufferSize,
        ref int lpBytesReturned,
        IntPtr lpOverlapped);
    [DllImport("kernel32")]
    private static extern bool DeviceIoControl (
        IntPtr hDevice,
        int dwIoControlCode,
        IntPtr lpInBuffer,
        int nInBufferSize,
        [MarshalAs(UnmanagedType.LPArray)] byte[] lpOutBuffer,
        int nOutBufferSize,
        ref int lpBytesReturned,
        IntPtr lpOverlapped);

    //ferme un fichier ou un pAcriphAcrique
    [DllImport("kernel32")]
    private static extern int CloseHandle(IntPtr hObject);

#region IOCTL
    private const int FILE_DEVICE_VIDEO = 0x23;

    private const int FILE_ANY_ACCESS = 0;
    private const int FILE_SPECIAL_ACCESS = FILE_ANY_ACCESS;

    private const int METHOD_BUFFERED = 0;
    private const int METHOD_NEITHER = 3;

    private const int ERROR_INSUFFICIENT_BUFFER = 122;

    /// <summary>
    /// GA‥re la dAcfinition d'un code de requAate d'un pAcriphAcrique en fonction de ses catAcgories
    /// </summary>
    /// <param name="dwDeviceType">Type de pAcriphAcrique</param>
    /// <param name="dwFunction">RequAate</param>
    /// <param name="dwMethod">MActhode de la requAate</param>
    /// <param name="dwAccess">Mode d'accA‥s</param>
    /// <returns></returns>
    /// <remarks></remarks>
    private static int CTL_CODE(int dwDeviceType, int dwFunction, int dwMethod, int dwAccess)
    {
      return ((dwDeviceType) << 16) | ((dwAccess) << 14) | ((dwFunction) << 2) | (dwMethod);
    }

    //requAate de lecture des niveaux d'Aclcairage supportAcs
    private static int IOCTL_VIDEO_QUERY_SUPPORTED_BRIGHTNESS = CTL_CODE(FILE_DEVICE_VIDEO, 293, METHOD_BUFFERED, FILE_ANY_ACCESS);
    //requAate de lecture des niveaux d'Acclairage en cours
    private static int IOCTL_VIDEO_QUERY_DISPLAY_BRIGHTNESS = CTL_CODE(FILE_DEVICE_VIDEO, 294, METHOD_BUFFERED, FILE_ANY_ACCESS);
    //requAate de dAcfinition des niveaux d'Acclairage en cours
    private static int IOCTL_VIDEO_SET_DISPLAY_BRIGHTNESS = CTL_CODE(FILE_DEVICE_VIDEO, 295, METHOD_BUFFERED, FILE_ANY_ACCESS);
#endregion

    /// <summary>
    /// Ouvre un handle vers le pAcriphAcrique LCD
    /// </summary>
    /// <returns></returns>
    /// <remarks></remarks>
    private IntPtr OpenLCD()
    {
      //ouverture en lecture partagAce
      return CreateFile("\\\\.\\LCD", GENERIC_READ, SHARE_ALL, IntPtr.Zero, OPEN_EXISTING, 0, IntPtr.Zero);
    }

    private byte[] mBrightness = null;
    /// <summary>
    /// Renvoie la liste des niveaux d'Acclairage supportAcs
    /// </summary>
    /// <value></value>
    /// <returns></returns>
    /// <remarks></remarks>
    public byte[] SupportedBrightness {
      get {
        if (mBrightness == null) {
          int lpRet=0;
          byte[] ret;
          //essaie d'ouvrir le LCD
          IntPtr pDisplay = OpenLCD();
          //si erreur, probablement pas un portable
          if (pDisplay != new IntPtr(-1)) {
              ret = new byte[256];

            //envoie la requAate des niveaux supportAcs
            if (DeviceIoControl(pDisplay, IOCTL_VIDEO_QUERY_SUPPORTED_BRIGHTNESS, IntPtr.Zero, 0, ret, 256, ref lpRet, IntPtr.Zero)) {
              //rAccupA‥re un tableau d'octet contenant les niveaux
                mBrightness = new byte[lpRet];

              for (int i = 0; i < lpRet; i++) {
                mBrightness[i] = ret[i];
              }
            }

            CloseHandle(pDisplay);
          }
        }
        return mBrightness;
      }
    }

    /// <summary>
    /// Renvoie l'Acclairage en cours
    /// </summary>
    /// <returns>Eclairage en cours par modes d'alimentation</returns>
    /// <remarks></remarks>
    public Brightness GetBrightness()
    {
      int lpRet=0;
      Brightness ret = null;
      //essaie d'ouvrir le LCD
      IntPtr pDisplay = OpenLCD();
      //si erreur, probablement pas un portable
      if (pDisplay == new IntPtr(-1))
        return null;

      //envoie la requAate de lecture de l'Acclairage en cours
      DISPLAY_BRIGHTNESS pBrightness = new DISPLAY_BRIGHTNESS();
      if (DeviceIoControl(pDisplay, IOCTL_VIDEO_QUERY_DISPLAY_BRIGHTNESS, IntPtr.Zero, 0, ref pBrightness, Marshal.SizeOf(typeof(DISPLAY_BRIGHTNESS)), ref lpRet, IntPtr.Zero)) {
        //si OK, rAccupA‥re la valeur pour AC/Alimentation et DC/Batterie
        ret = new Brightness();
        ret.AC = pBrightness.ucACBrightness;
        ret.DC = pBrightness.ucDCBrightness;
      }

      CloseHandle(pDisplay);

      return ret;
    }

    /// <summary>
    /// DAcfinit l'Acclairage A  la mAame valeur pour les deux modes d'alimentation
    /// </summary>
    /// <param name="brightness">Niveau d'Acclairage</param>
    /// <returns>true si rAcussi, false sinon</returns>
    /// <remarks></remarks>
    public bool SetBrightness(int brightness)
    {
      return SetBrightness(brightness, brightness);
    }

    /// <summary>
    /// DAcfinit l'Acclairage par mode d'alimentation
    /// </summary>
    /// <param name="acBrightness">Niveau AC/Alimentation</param>
    /// <param name="dcBrightness">Niveau DC/Batterie</param>
    /// <returns>true si rAcussi, false sinon</returns>
    /// <remarks></remarks>
    public bool SetBrightness(int acBrightness, int dcBrightness)
    {
      bool ret;
      int lpRet=0;
      //essaie d'ouvrir le LCD
      IntPtr pDisplay = OpenLCD();
      //si erreur, probablement pas un portable
      if (pDisplay == new IntPtr(-1))
        return false;

      //remplit la structure et informe que l'on dAcfinit les deux valeurs
      DISPLAY_BRIGHTNESS pBrightness = new DISPLAY_BRIGHTNESS();
      pBrightness.ucACBrightness = (byte)(acBrightness & 0xFF);
      pBrightness.ucDCBrightness = (byte)(dcBrightness & 0xFF);
      pBrightness.ucDisplayPolicy = DISPLAYPOLICY_BOTH;

      //envoie la requAate de dAcfinition de l'Acclairage au pAcriphAcrique LCD
      ret = DeviceIoControl(pDisplay, IOCTL_VIDEO_SET_DISPLAY_BRIGHTNESS, ref pBrightness, Marshal.SizeOf(pBrightness), IntPtr.Zero, 0, ref lpRet, IntPtr.Zero);

      CloseHandle(pDisplay);

      return ret;
    }
  }
}

參考原始出處：http://codes-sources.commentcamarche.net/source/view/53617/1259513#browser

Keyword：C#, Windows, Backlight

2012/10/31

【Windows8】取得Auto Rotation狀態

先前同事提了個需求要能用程式判斷當前Auto Rotation狀態，查了一下發現有個GetAutoRotationState()函數可以調用，透過這函數呼叫可以查知目前系統Auto Rotation是否被開啟，直接看程式內容吧！

#include <Windows.h>
#include <tchar.h>
#include <stdio.h>

#pragma comment (lib, "User32")

int _tmain(int argc, _TCHAR* argv[])
{
 enum tagAR_STATE state;
 bool blResult = GetAutoRotationState(&state);
 if(blResult)
 {
  if(0 == state)
   printf("Auto Rotation: ON\n");
  else
   printf("Auto Rotation: OFF\n");
 }
 else
  printf("Access rotation status ... fail\n");
 return  0;
}

需要注意的是這函數是Windows8才加入User32.dll的，因此如果拿這程式在Windows7以前版本執行的話會遇到這樣的錯誤：

如果要避免這樣的錯誤，需要用動態載入dll方式進行呼叫。

在Windows8上執行截圖如下：

附註：tagAR_STATE詳細屬性：

public enum tagAR_STATE : uint
{
 AR_ENABLED = 0x0,
 AR_DISABLED = 0x1,
 AR_SUPPRESSED = 0x2,
 AR_REMOTESESSION = 0x4,
 AR_MULTIMON = 0x8,
 AR_NOSENSOR = 0x10,
 AR_NOT_SUPPORTED = 0x20,
 AR_DOCKED = 0x40,
 AR_LAPTOP = 0x80
}

Keyword：Windows API、System Call

2012/8/29

【C++】縮小命令提示字元視窗

上次寫了如何用C#讓命令提示字元視窗在執行時縮小（參考這篇），今天又有同事提出需求要在另一支用C++完成的工具也要做到一樣效果，有了上次的經驗這次很快就完成了任務需求，一樣用FindWindow與ShowWindow系統函數來達成，只是這次要多調用一個GetConsoleTitle函數來做輔助，直接看Code：

#include <stdio.h>
#include <Windows.h>

#pragma comment(lib, "User32.lib")

int main(int argc, char* argv[])
{
 char cTitle[512];
 GetConsoleTitle(cTitle, 512);
 HWND hWnd = FindWindow(NULL, cTitle);
 ShowWindow(hWnd, SW_SHOWMINIMIZED);
 return 0;
}

先用GetConsoleTitle函數取得執行程式命令提示字元的顯示標題列內容。
再用取得的視窗標題找出HWND。
最後用FindWindow函數控制視窗的呈現。

ShowWindow第二個函數用來決定視窗要如何呈現：最大、最小...等。詳細請參考MSDN說明頁面。

2012/8/15

【C#】縮小命令提示字元視窗

今天同事提了個奇怪的需求：執行程式時要能把命令提是字元視窗縮小，查了一下網路發現可以利用FindWindow()與ShowWindow()兩個函數達成此需求，直接看以下範例：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace HideConsole
{
    class Program
    {
        static void Main(string[] args)
        {
            IntPtr ParenthWnd = new IntPtr(0);
            
            ParenthWnd = Findindow(null, Console.Title);
            if (ParenthWnd == IntPtr.Zero)
                Console.WriteLine("Find Window ... FAIL");
            else
                ShowWindow(ParenthWnd, SW_SHOWMINIMIZED);
        }

        [DllImport("user32.dll", EntryPoint = "FindWindow")]
        private static extern IntPtr Findindow(string lpClassName, string lpWindowName);
        [DllImport("user32.dll", EntryPoint = "ShowWindow")]
        private static extern IntPtr ShowWindow(IntPtr hWnd, int type);
        const int SW_HIDE = 0;
        const int SW_SHOWMINIMIZED = 2;
        const int SW_MAXIMIZE = 3;
    }
}

流程說明：

用Console.Title找出命令提示字元視窗本身的標題字串，並透過FindWindow找出Handler
將Handler傳給ShowWindow函數，並傳入參數讓視窗進行改變，範例標了幾個視窗屬性SW_HIDE, SW_SHOWMINIMIZED與SW_MAXIMIZE，完整的參數可以參考MSDN的參考網頁（ http://msdn.microsoft.com/en-us/library/windows/desktop/ms633548(v=vs.85).aspx）

因使用了DllImport，記得要加入

1	using System.Runtime.InteropServices;

Keyword：How to Minimize Terminal on Windows、C# Programming、Minimize Command Prompt on Windows