C# & vb .Net Codes and components...

Wake On LAN (WOL) in C#

2009-05-11T14:57:00.000-07:00

I was looking for something to wake my remote machine on LAN or a different laptop connected in my network to wake up without having to press the power button again and again. There are some programs available but you have to pay for them. It's pretty easy to make a packet (so called magic packet) and broadcast it in the network. The packet contains the MAC address of the machine which has to be woken up. If that machine is in network and is connected via a LAN cable, it should wake itself up. So here is the program in C# which creates the magic packet and broadcasts it in the network. You might also like to check my post on Get MAC address from hostname or IP address to integrate this program and the other one together so you will just have to enter the hostname/IP address of the machine which you want woken up without worrying about it's MAC address. If you want just the exe, let me know via a comment here and I'll send you the executable.

1 // No copyrights(c). Use as you wish!

3 using System;

4 using System.Globalization;

5 using System.Text.RegularExpressions;

6 using System.Net;

7 using System.Net.Sockets;

9 namespace Yours.Truly

10 {

11 // *************************************************************************

12 /// <summary>

13 /// A class to demonstrate Wake up on LAN. For this program to function, your

14 /// machine must be setup to accept wake-up on LAN requests. Usually this

15 /// option can set to "Enabled" state in boot(BIOS) options. You can see the

16 /// set value by Rebooting your PC/Laptop and press F2 just after you power

17 /// on your PC/Laptop. (you might have to keep pressing F2 until it comes up

18 /// with boot options)

19 /// </summary>

20 /// <remarks>

21 /// <para>

22 /// For more information see http://support.microsoft.com/kb/257277 and

23 /// http://en.wikipedia.org/wiki/Wake-on-LAN.

24 /// </para>

25 /// <para>For an in depth details please visit :

26 /// http://en.wikipedia.org/wiki/Data_link_layer and

27 /// http://en.wikipedia.org/wiki/Network_layer </para>

28 /// </remarks>

29 public sealed class WakeUpOnLan

30 {

31 // *********************************************************************

32 /// <summary>

33 /// Main entry point of the application.

34 /// </summary>

35 /// <param name="args">An array of command line arguments.</param>

36 static void Main(string[] args)

37 {

38 bool wakeUp = true;

39 while (wakeUp)

40 {

41 Console.WriteLine("Enter the MAC address of the host to wake up " +

42 " on LAN (no space or hyphen(-). e.g. 0021702BA7A5." +

43 "Type Exit to end the program):");

44 string macAddress = Console.ReadLine();

46 StringComparer cp = StringComparer.OrdinalIgnoreCase;

47 if (cp.Compare(macAddress, "Exit") == 0) break;

49 //remove all non 0-9, A-F, a-f characters

50 macAddress = Regex.Replace(macAddress, @"[^0-9A-Fa-f]", "");

51 //check if mac adress length is valid

52 if (macAddress.Length != 12)

53 {

54 Console.WriteLine("Invalid MAC address. Try again!");

55 }

56 else

57 {

58 Wakeup(macAddress);

59 }

60 }

61 }

63 // *********************************************************************

64 /// <summary>

65 /// Wakes up the machine with the given <paramref name="macAddress"/>.

66 /// </summary>

67 /// <remarks>

68 /// <para>

69 /// <note>

70 /// <list type="number">

71 /// <item> The motherboard must support Wake On LAN.</item>

72 /// <item> The NIC must support Wake On LAN.</item>

73 /// <item> There must be a wire connecting the motherboard's WOL port to

74 /// the NIC's WOL port. Usually there always is a connection on most of

75 /// the PCs.</item>

76 /// <item> The Wake On LAN feature must be enabled in the motherboard's

77 /// BIOS. Usually this is also enabled by default, but you might like to

78 /// check again.</item>

79 /// <item> The "Good Connection" light on the back of the NIC must be lit

80 /// when the machine is off. (By default always good if you are not

81 /// facing any network issues)</item>

82 /// <item> Port 12287 (0x2FFF) must be open. (By default it should be

83 /// open unless some antivirus or any other such program has changed

84 /// settings.)</item>

85 /// <item> Packets cannot be broadcast across the Internet. That's why

86 /// it's called Wake On Lan, not Wake On Internet.</item>

87 /// <item> To find your MAC address, run the MSINFO32.EXE tool that is a

88 /// part of Windows and navigate to Components > Network > Adapteror

89 /// or simply type nbtstat -a <your hostname &lt at command prompt.

90 /// e.g. nbtstat -a mymachinename or nbtstat -A 10.2.100.213.

91 /// .</item>

92 /// </list>

93 /// </note>

94 /// </para>

95 /// <para>You could also use my other blog on "Get MAC address" to simply

96 /// integrate this program and my other program so you just have to input

97 /// the hostname/IP address of the machine which you want woken up.</para>

98 /// <para>See http://mycomponent.blogspot.com/2009/05/get-mac-address-in-c-from-ip.html

99 /// </para>

100 /// </remarks>

101 /// <param name="macAddress">The MAC address of the host which has to be

102 /// woken up.</param>

103 private static void Wakeup(string macAddress)

104 {

105 WOLUdpClient client = new WOLUdpClient();

106 client.Connect(

107 new IPAddress(0xffffffff), //255.255.255.255 i.e broadcast

108 0x2fff); // port = 12287

109 // Set the socketoptions

110 if (client.IsClientInBrodcastMode())

111 {

112 int byteCount = 0;

113 // buffer to be sent:

114 // 6 bytes each with 255 + 16 times mac each 6 bytes

115 byte[] bytes = new byte[102];

116 // The packet begins with 6 bytes trailer of FF bytes which is

117 // followed by 16 times repeated MAC address of the target device

118 // (i.e. the device that should be switched on). MAC Address is

119 // used as an identifier in the packet, because that is the only

120 // valuable identification that is available when the PC is not

121 // running. MAC Address is assigned by the manufacturer (it is

122 // a layer 2 - Data link layer identifier) and it stored in the

123 // flash memory of the network card itself, so the network card

124 // can perform the comparison very easily. It cannot use an IP

125 // address, because network card simply does not have one when

126 // PC is not running - IP address is a layer 3 - network layer

127 // identifier, which means it is assigned by the OS.

128 // You may also ask why the MAC address is repeated 16 times?

129 // As mentioned above the network card scans all packets that

130 // are coming in and it does not support any protocols of higher

131 // levels (TCP, HTTP, etc.) - it will literally go through all

132 // bytes in the packet and if it finds the "magic packet"

133 // sequence anywhere in the data or even a packet header, it

134 // will turn on the PC. Imagine that the packet did not repeat

135 // the MAC Address, so it would only utilise 6 bytes of FF and

136 // then 6 bytes of the MAC address. This 12 bytes combination

137 // may sooner or later appear in your network communication

138 // (in a file transfer, incoming email, a picture, etc.). 12

139 // bytes is just not enough, which is why the MAC address is

140 // repeated 16 times giving the packet solid 102 bytes. The

141 // probability that those 102 bytes will unintentionally appear

142 // in transferred data is exponentially lower (there are

143 // 256^102 different packets which should be safe enough).

144

145 // First 6 bytes should be 0xFF

146 for (int trailer = 0; trailer < 6; trailer++)

147 {

148 bytes[byteCount++] = 0xFF;

149 }

150 // Repeat MAC 16 times

151 for (int macPackets = 0; macPackets < 16; macPackets++)

152 {

153 int i = 0;

154 for (int macBytes = 0; macBytes < 6; macBytes++)

155 {

156 bytes[byteCount++] =

157 byte.Parse(macAddress.Substring(i, 2),

158 NumberStyles.HexNumber);

159 i += 2;

160 }

161 }

162

163 // Send wake up packet (the magic packet!)

164 int returnValue = client.Send(bytes, byteCount);

165 Console.WriteLine(returnValue + " bytes sent to " + macAddress +

166 Environment.NewLine + "Check if it's woken up. If not, try again!" +

167 Environment.NewLine);

168 }

169 else

170 {

171 Console.WriteLine("Remote client could not be set in broadcast mode!");

172 }

173 } // end Wakeup

174

175 } // end class WakeUpOnLan

176

177 // *************************************************************************

178 /// <summary>

179 /// A <see cref="UdpClient"/> class to set the client to broadcast mode.

180 /// </summary>

181 /// <remarks>

182 /// <para>

183 /// This class just sets the SocketOption to

184 /// <see cref="SocketOptionName.Broadcast"/> mode.

185 /// </para>

186 /// </remarks>

187 public class WOLUdpClient : UdpClient

188 {

189 // *********************************************************************

190 /// <summary>

191 /// Initializes a new instance of <see cref="WOLUdpClient"/>.

192 /// </summary>

193 public WOLUdpClient() : base()

194 {

195 }

196

197 // *********************************************************************

198 /// <summary>

199 /// Sets up the UDP client to broadcast packets.

200 /// </summary>

201 /// <returns><see langword="true"/> if the UDP client is set in

202 /// broadcast mode.</returns>

203 public bool IsClientInBrodcastMode()

204 {

205 bool broadcast = false;

206 if (this.Active)

207 {

208 try

209 {

210 this.Client.SetSocketOption(SocketOptionLevel.Socket,

211 SocketOptionName.Broadcast, 0);

212 broadcast = true;

213 }

214 catch

215 {

216 broadcast = false;

217 }

218 }

219 return broadcast;

220 }

221

222 } // end class WOLUdpClient

223 } // end namespace Yours.Truly

Get MAC Address in C# from IP Address/Hostname

2009-05-11T14:45:00.000-07:00

I was hoping to find something to get MAC address of a machine given its IP address or hostname. There could be multiple ways to do the same. But I thought I'll give the "nbtstat" a chance. nbtstat is a command in windows which gets you the details about protocol statistics and current TCP/IP connections using NBT (NetBIOS over TCP/IP). Here is a small program in C# which does the exact same thing: (If you want just the exe, let me know via a comment here and I'll send you the executable.)

1 // No copyrights(c). Use as you wish!

3 using System;

4 using System.Diagnostics;

5 using System.Net;

6 using System.Net.NetworkInformation;

7 using System.Runtime.InteropServices;

8 using System.Text;

10 namespace Yours.Truly

11 {

12 // *************************************************************************

13 /// <summary>

14 /// A class to get the MAC address from IP address. The same class can be

15 /// modified a little to get the MAC address from the specified hostname.

16 /// </summary>

17 public class GetMacAddressFromIPAddress

18 {

19 /// <summary> Ping timeout (in ms) </summary>

20 private const int PING_TIMEOUT = 1000;

22 // *********************************************************************

23 /// <summary>

24 /// Initializes a new instance of <see cref="GetMacAddressFromIPAddress"/>.

25 /// </summary>

26 public GetMacAddressFromIPAddress()

27 {

28 }

30 // *********************************************************************

31 /// <summary>

32 /// Gets the MAC address from specified <paramref name="IPAddress"/>

33 /// using nbtstat in hyphen (-) separated format.

34 /// </summary>

35 /// <remarks>

36 /// <para>

37 /// The same class can be modified to accept hostname and then resolve

38 /// the hostname to Ip address to get the MAC address or just pass "-a"

39 /// argument to "nbtstat" to get the mac address from hostname. If you

40 /// want to find the MAC address from only the IP address change the

41 /// switch to "-A".

42 /// </para>

43 /// <para>

44 /// The current program can resolve both hostname as well as IP address

45 /// to MAC address. The "-a" argument can actually accept both IP address

46 /// as well as hostname.

47 /// </para>

48 /// </remarks>

49 /// <param name="ipAddress">The IP address or hostname for the machine

50 /// for which the MAC address is desired.</param>

51 /// <returns>A string containing the MAC address if MAC address could be

52 /// found.An empty or null string otherwise.</returns>

53 private string GetMacAddress(string ipAddress)

54 {

55 string macAddress = string.Empty;

57 if (!IsHostAccessible(ipAddress)) return null;

58 try

59 {

60 ProcessStartInfo processStartInfo = new ProcessStartInfo();

61 Process process = new Process();

62 processStartInfo.FileName = "nbtstat";

63 processStartInfo.RedirectStandardInput = false;

64 processStartInfo.RedirectStandardOutput = true;

65 processStartInfo.Arguments = "-a " + ipAddress;

66 processStartInfo.UseShellExecute = false;

67 process = Process.Start(processStartInfo);

69 int Counter = -1;

71 while (Counter <= -1)

72 {

73 // Look for the words "mac address" in the output.

74 // The output usually looks likes this:

76 // Local Area Connection:

77 //Node IpAddress: [13.15.111.222] Scope Id: []

79 // NetBIOS Remote Machine Name Table

81 // Name Type Status

82 // --------------------------------------------

83 // SAMGLS0790W <00> UNIQUE Registered

84 // SAMPLS0790W <20> UNIQUE Registered

85 // NA <00> GROUP Registered

87 // MAC Address = 00-21-70-2B-A5-43

89 Counter =

90 macAddress.Trim().ToLower().IndexOf("mac address", 0);

91 if (Counter > -1)

92 {

93 break;

94 }

95 macAddress = process.StandardOutput.ReadLine();

96 }

97 process.WaitForExit();

98 macAddress = macAddress.Trim();

99 }

100 catch (Exception e)

101 {

102 // Something unexpected happened? Inform the user

103 // The possibilities are:

104 // 1.That the machine is not on the network currently

105 // 2. The IP address/hostname supplied are not on the same network

106 // 3. The host was not found on the same subnet or could not be

107 // resolved

108 Console.WriteLine("Failed because:" + e.ToString());

109 }

110

111 return macAddress;

112 }

113

114 #region Getting MAC from ARP

115

116 [DllImport("iphlpapi.dll", ExactSpelling = true)]

117 static extern int SendARP(int DestIP, int SrcIP, byte[] pMacAddr,

118 ref uint PhyAddrLen);

119

120 // *********************************************************************

121 /// <summary>

122 /// Gets the MAC address from ARP table in colon (:) separated format.

123 /// </summary>

124 /// <param name="hostNameOrAddress">Host name or IP address of the

125 /// remote host for which MAC address is desired.</param>

126 /// <returns>A string containing MAC address; null if MAC address could

127 /// not be found.</returns>

128 private string GetMACAddressFromARP(string hostNameOrAddress)

129 {

130 if (!IsHostAccessible(hostNameOrAddress)) return null;

131

132 IPHostEntry hostEntry = Dns.GetHostEntry(hostNameOrAddress);

133 if (hostEntry.AddressList.Length == 0)

134 return null;

135

136 byte[] macAddr = new byte[6];

137 uint macAddrLen = (uint) macAddr.Length;

138 if (SendARP((int) hostEntry.AddressList[0].Address, 0, macAddr,

139 ref macAddrLen) != 0)

140 return null;

141

142 StringBuilder macAddressString = new StringBuilder();

143 for (int i = 0; i < macAddr.Length; i++)

144 {

145 if (macAddressString.Length > 0)

146 macAddressString.Append(":");

147

148 macAddressString.AppendFormat("{0:x2}", macAddr[i]);

149 }

150

151 return macAddressString.ToString();

152 } // end GetMACAddressFromARP

153

154 #endregion Getting MAC from ARP

155

156 // *********************************************************************

157 /// <summary>

158 /// Checks to see if the host specified by

159 /// <paramref name="hostNameOrAddress"/> is currently accessible.

160 /// </summary>

161 /// <param name="hostNameOrAddress">Host name or IP address of the

162 /// remote host for which MAC address is desired.</param>

163 /// <returns><see langword="true" /> if the host is currently accessible;

164 /// <see langword="false"/> otherwise.</returns>

165 private static bool IsHostAccessible(string hostNameOrAddress)

166 {

167 Ping ping = new Ping();

168 PingReply reply = ping.Send(hostNameOrAddress, PING_TIMEOUT);

169 return reply.Status == IPStatus.Success;

170 }

171

172 // *********************************************************************

173 /// <summary>

174 /// The netry point for the application.

175 /// </summary>

176 /// <param name="args">An array of command line arguments.</param>

177 [STAThread]

178 static void Main(string[] args)

179 {

180 bool macRequired = true;

181 while (macRequired)

182 {

183 Console.WriteLine("Enter the IP address for which mac address is " +

184 "required:(Enter exit to quit the program.)");

185 string ipAddress = Console.ReadLine();

186 StringComparer cp = StringComparer.OrdinalIgnoreCase;

187 if (cp.Compare(ipAddress, "Exit") == 0) break;

188

189 GetMacAddressFromIPAddress getMacAddress =

190 new GetMacAddressFromIPAddress();

191

192 Console.WriteLine("Please wait while I try to find the MAC address...");

193 // You may also use the ARP table. Call GetMACAddressFromARP here

194 string MacAddress = getMacAddress.GetMacAddress(ipAddress);

195

196 Console.WriteLine(MacAddress);

197 } // end while

198 }

199

200 } // end class GetMacAddressFromIPAddress

201

202 } // end namespace Yours.Truly

Set Screen Brightness/Contrast in C#

2009-05-09T15:53:00.000-07:00

I loaded Microsoft Windows Vista Business operating System on my old Toshiba Tecra A4 laptop and then realized that my Fn key is no longer working. The software and drivers that came with my laptop were not compatible with Vista. Alas, the one thing that I missed the most was setting up the brightness using Fn+F6 key. Usually when Windows starts, my LCD screen is just so bright that I have to adjust the brightness every time I start my laptop. Now, that leisure was gone. So I thought why not give it a try in C#. Found an API on MSDN and used it here in C# to make it work for me. It's not that great a program but a stupid slider to just reduce the Gamma component to give you a feeling that brightness is reduced. Actually the contrast is reduced. See the full code here. You can just copy and paste the full code in a Form class in a new Windows project and hit F5. If one of you is interested in just the executable, let me know via your comment here so I can send you the exe if you so desire.

1 // No copyrights (c). Use it as you wish!!

3 using System;

4 using System.Runtime.InteropServices;

5 using System.Windows.Forms;

7 namespace Yours.Truly

8 {

9 // *************************************************************************

10 /// <summary>

11 /// A form class to demnstrate the brightness adjustment for computer

12 /// monitors.

13 /// </summary>

14 /// <remarks>

15 /// <para>

16 /// It uses the Interop <see cref="SetDeviceGammaRamp"/> call to set the

17 /// Gamma component to adjust the screen contrast.

18 /// </para>

19 /// <para>

20 /// The <see cref="SetDeviceGammaRamp"/> function sets the gamma ramp on

21 /// direct color display boards having drivers that support downloadable

22 /// gamma ramps in hardware.

23 /// </para>

24 /// <para>

25 /// Direct color display modes do not use color lookup tables and are

26 /// usually 16, 24, or 32 bit. Not all direct color video boards support

27 /// loadable gamma ramps. SetDeviceGammaRamp succeeds only for devices with

28 /// drivers that support downloadable gamma ramps in hardware.

29 /// </para>

30 /// </remarks>

31 public class SetBrightness : Form

32 {

33 // *********************************************************************

34 /// <summary>

35 /// A structure of gamma corrections.

36 /// </summary>

37 [StructLayout(LayoutKind.Sequential, CharSet=CharSet.Ansi)]

38 private struct RAMP

39 {

40 [ MarshalAs(UnmanagedType.ByValArray, SizeConst=256)]

41 public UInt16[] Red;

42 [ MarshalAs(UnmanagedType.ByValArray, SizeConst=256)]

43 public UInt16[] Green;

44 [ MarshalAs(UnmanagedType.ByValArray, SizeConst=256)]

45 public UInt16[] Blue;

46 }

48 [DllImport("gdi32.dll")]

49 private static extern bool SetDeviceGammaRamp(IntPtr hDC, ref RAMP lpRamp);

51 [DllImport("user32.dll")]

52 static extern IntPtr GetDC(IntPtr hWnd);

54 /// <summary> Required designer variable.</summary>

55 private System.ComponentModel.IContainer components = null;

56 private TrackBar m_trackBar;

58 private static RAMP s_ramp = new RAMP();

60 // *********************************************************************

61 /// <summary>

62 /// Initializes a new instance of <see cref="SetBrightness"/> class.

63 /// </summary>

64 public SetBrightness ()

65 {

66 InitializeComponent();

67 }

69 // *********************************************************************

70 /// <summary>

71 /// Clean up any resources being used.

72 /// </summary>

73 /// <param name="disposing">true if managed resources should be

74 /// disposed; otherwise, false.</param>

75 protected override void Dispose (bool disposing)

76 {

77 if (disposing && (components != null))

78 {

79 components.Dispose();

80 }

81 base.Dispose(disposing);

82 }

84 // *********************************************************************

85 /// <summary>

86 /// Handles the <see cref="TrackBar.ValueChanged"/> event for the TrackBar

87 /// control. The value of the track bar control sets the Gamma value for

88 /// the device.

89 /// </summary>

90 /// <param name="sender">The object that initiated the event.</param>

91 /// <param name="e">An <see cref="EventArgs"/> object containing event

92 /// data</param>

93 private void HandleValueChanged (object sender, EventArgs e)

94 {

95 SetGamma(m_trackBar.Value);

96 }

98 // *********************************************************************

99 /// <summary>

100 /// Main entry point for the application.

101 /// </summary>

102 /// <param name="args">An array of optional arguments.</param>

103 static void Main (string[] args)

104 {

105 SetBrightness mainForm = new SetBrightness();

106 Application.Run(mainForm);

107 }

108

109 // *********************************************************************

110 /// <summary>

111 /// Sets the Gamma corection at the specified <paramref name="gamma"/>

112 /// value.

113 /// </summary>

114 /// <param name="gamma">New Gamma value to be set.</param>

115 private static void SetGamma(int gamma)

116 {

117 s_ramp.Red = new ushort[256];

118 s_ramp.Green = new ushort[256];

119 s_ramp.Blue = new ushort[256];

120

121 for( int i=1; i<256; i++ )

122 {

123 // gamma is a value between 3 and 44

124 s_ramp.Red[i] = s_ramp.Green[i] = s_ramp.Blue[i] =

125 (ushort)(Math.Min(65535,

126 Math.Max(0, Math.Pow((i+1) / 256.0, gamma*0.1) * 65535 + 0.5)));

127 }

128 // Now set the value.

129 SetDeviceGammaRamp(GetDC(IntPtr.Zero), ref s_ramp);

130 }

131

132 #region Windows Form Designer generated code

133

134 /// <summary>

135 /// Required method for Designer support - do not modify

136 /// the contents of this method with the code editor.

137 /// </summary>

138 private void InitializeComponent ()

139 {

140 this.m_trackBar = new System.Windows.Forms.TrackBar();

141 ((System.ComponentModel.ISupportInitialize)(this.m_trackBar)).BeginInit();

142 this.SuspendLayout();

143 //

144 // m_trackBar

145 //

146 this.m_trackBar.Dock = System.Windows.Forms.DockStyle.Fill;

147 this.m_trackBar.Location = new System.Drawing.Point(0,0);

148 this.m_trackBar.Maximum = 44;

149 this.m_trackBar.Minimum = 3;

150 this.m_trackBar.Name = "m_trackBar";

151 this.m_trackBar.RightToLeft = System.Windows.Forms.RightToLeft.Yes;

152 this.m_trackBar.RightToLeftLayout = true;

153 this.m_trackBar.Size = new System.Drawing.Size(277,42);

154 this.m_trackBar.TabIndex = 0;

155 this.m_trackBar.Value = 18;

156 this.m_trackBar.ValueChanged += new System.EventHandler(this.HandleValueChanged);

157 //

158 // SetBrightness

159 //

160 this.AutoScaleDimensions = new System.Drawing.SizeF(6F,13F);

161 this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;

162 this.ClientSize = new System.Drawing.Size(277,42);

163 this.Controls.Add(this.m_trackBar);

164 this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog;

165 this.MaximizeBox = false;

166 this.MinimizeBox = false;

167 this.Name = "SetBrightness";

168 this.Opacity = 0.8;

169 this.ShowIcon = false;

170 this.SizeGripStyle = System.Windows.Forms.SizeGripStyle.Hide;

171 this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;

172 this.Text = "SetBrightness";

173 this.TopMost = true;

174 ((System.ComponentModel.ISupportInitialize)(this.m_trackBar)).EndInit();

175 this.ResumeLayout(false);

176 this.PerformLayout();

177

178 }

179

180 #endregion

181

182 } // end class SetBrightness

183 } // end namespace Yours.Truly