DialogUtil openFolder = new DialogUtil();
            if (openFolder.ShowFolderDialog() == DialogResult.OK)
            {
                DirectoryInfo source = new DirectoryInfo(openFolder.Path);
                foreach (FileInfo fi in source.GetFiles("*.jpg"))
                {
                    ExifManager exif = new ExifManager(fi.FullName);
                    exif.DateTimeOriginal = exif.DateTimeOriginal.AddHours(12);
                    exif.DateTimeDigitized = exif.DateTimeDigitized.AddHours(12);
                    exif.Save(fi.DirectoryName + "\\new\\" + fi.Name);
                    exif.Dispose();
                }
            }

using System;
using System.Collections.Generic;
using System.Text;

namespace ExifShow
{
//
// Utility class for working with EXIF data in images. Provides abstraction
// for most common data and generic utilities for work with all other.
//
//
// Copyright (c) Michal A. Valášek - Altair Communications, 2003-2005
// Copmany: http://software.altaircom.net, E-mail: support@altaircom.net
// Private: http://www.rider.cz, E-mail: rider@rider.cz
// This is free software licensed under GNU Lesser General Public License
//
//
// [altair] 10.09.2003 Created
// [altair] 12.06.2004 Added capability to write EXIF data
// [altair] 11.07.2004 Added option to change encoding
// [altair] 04.09.2005 Changed source of Width and Height properties from EXIF to image
// [altair] 05.09.2005 Code clean-up and minor changes
// [marco.ridoni@virgilio.it] 02-11-2006 C# translation
//
public class ExifManager : IDisposable
{

private System.Drawing.Bitmap _Image;
private System.Text.Encoding _Encoding = System.Text.Encoding.UTF8;

#region Type declarations

//
// Contains possible values of EXIF tag names (ID)
//
// See GdiPlusImaging.h
//
// [altair] 10.09.2003 Created
//

public enum TagNames : int
{
ExifIFD = 0x8769,
GpsIFD = 0x8825,
NewSubfileType = 0xFE,
SubfileType = 0xFF,
ImageWidth = 0x100,
ImageHeight = 0x101,
BitsPerSample = 0x102,
Compression = 0x103,
PhotometricInterp = 0x106,
ThreshHolding = 0x107,
CellWidth = 0x108,
CellHeight = 0x109,
FillOrder = 0x10A,
DocumentName = 0x10D,
ImageDescription = 0x10E,
EquipMake = 0x10F,
EquipModel = 0x110,
StripOffsets = 0x111,
Orientation = 0x112,
SamplesPerPixel = 0x115,
RowsPerStrip = 0x116,
StripBytesCount = 0x117,
MinSampleValue = 0x118,
MaxSampleValue = 0x119,
XResolution = 0x11A,
YResolution = 0x11B,
PlanarConfig = 0x11C,
PageName = 0x11D,
XPosition = 0x11E,
YPosition = 0x11F,
FreeOffset = 0x120,
FreeByteCounts = 0x121,
GrayResponseUnit = 0x122,
GrayResponseCurve = 0x123,
T4Option = 0x124,
T6Option = 0x125,
ResolutionUnit = 0x128,
PageNumber = 0x129,
TransferFuncition = 0x12D,
SoftwareUsed = 0x131,
DateTime = 0x132,
Artist = 0x13B,
HostComputer = 0x13C,
Predictor = 0x13D,
WhitePoint = 0x13E,
PrimaryChromaticities = 0x13F,
ColorMap = 0x140,
HalftoneHints = 0x141,
TileWidth = 0x142,
TileLength = 0x143,
TileOffset = 0x144,
TileByteCounts = 0x145,
InkSet = 0x14C,
InkNames = 0x14D,
NumberOfInks = 0x14E,
DotRange = 0x150,
TargetPrinter = 0x151,
ExtraSamples = 0x152,
SampleFormat = 0x153,
SMinSampleValue = 0x154,
SMaxSampleValue = 0x155,
TransferRange = 0x156,
JPEGProc = 0x200,
JPEGInterFormat = 0x201,
JPEGInterLength = 0x202,
JPEGRestartInterval = 0x203,
JPEGLosslessPredictors = 0x205,
JPEGPointTransforms = 0x206,
JPEGQTables = 0x207,
JPEGDCTables = 0x208,
JPEGACTables = 0x209,
YCbCrCoefficients = 0x211,
YCbCrSubsampling = 0x212,
YCbCrPositioning = 0x213,
REFBlackWhite = 0x214,
ICCProfile = 0x8773,
Gamma = 0x301,
ICCProfileDescriptor = 0x302,
SRGBRenderingIntent = 0x303,
ImageTitle = 0x320,
Copyright = 0x8298,
ResolutionXUnit = 0x5001,
ResolutionYUnit = 0x5002,
ResolutionXLengthUnit = 0x5003,
ResolutionYLengthUnit = 0x5004,
PrintFlags = 0x5005,
PrintFlagsVersion = 0x5006,
PrintFlagsCrop = 0x5007,
PrintFlagsBleedWidth = 0x5008,
PrintFlagsBleedWidthScale = 0x5009,
HalftoneLPI = 0x500A,
HalftoneLPIUnit = 0x500B,
HalftoneDegree = 0x500C,
HalftoneShape = 0x500D,
HalftoneMisc = 0x500E,
HalftoneScreen = 0x500F,
JPEGQuality = 0x5010,
GridSize = 0x5011,
ThumbnailFormat = 0x5012,
ThumbnailWidth = 0x5013,
ThumbnailHeight = 0x5014,
ThumbnailColorDepth = 0x5015,
ThumbnailPlanes = 0x5016,
ThumbnailRawBytes = 0x5017,
ThumbnailSize = 0x5018,
ThumbnailCompressedSize = 0x5019,
ColorTransferFunction = 0x501A,
ThumbnailData = 0x501B,
ThumbnailImageWidth = 0x5020,
ThumbnailImageHeight = 0x502,
ThumbnailBitsPerSample = 0x5022,
ThumbnailCompression = 0x5023,
ThumbnailPhotometricInterp = 0x5024,
ThumbnailImageDescription = 0x5025,
ThumbnailEquipMake = 0x5026,
ThumbnailEquipModel = 0x5027,
ThumbnailStripOffsets = 0x5028,
ThumbnailOrientation = 0x5029,
ThumbnailSamplesPerPixel = 0x502A,
ThumbnailRowsPerStrip = 0x502B,
ThumbnailStripBytesCount = 0x502C,
ThumbnailResolutionX = 0x502D,
ThumbnailResolutionY = 0x502E,
ThumbnailPlanarConfig = 0x502F,
ThumbnailResolutionUnit = 0x5030,
ThumbnailTransferFunction = 0x5031,
ThumbnailSoftwareUsed = 0x5032,
ThumbnailDateTime = 0x5033,
ThumbnailArtist = 0x5034,
ThumbnailWhitePoint = 0x5035,
ThumbnailPrimaryChromaticities = 0x5036,
ThumbnailYCbCrCoefficients = 0x5037,
ThumbnailYCbCrSubsampling = 0x5038,
ThumbnailYCbCrPositioning = 0x5039,
ThumbnailRefBlackWhite = 0x503A,
ThumbnailCopyRight = 0x503B,
LuminanceTable = 0x5090,
ChrominanceTable = 0x5091,
FrameDelay = 0x5100,
LoopCount = 0x5101,
PixelUnit = 0x5110,
PixelPerUnitX = 0x5111,
PixelPerUnitY = 0x5112,
PaletteHistogram = 0x5113,
ExifExposureTime = 0x829A,
ExifFNumber = 0x829D,
ExifExposureProg = 0x8822,
ExifSpectralSense = 0x8824,
ExifISOSpeed = 0x8827,
ExifOECF = 0x8828,
ExifVer = 0x9000,
ExifDTOrig = 0x9003,
ExifDTDigitized = 0x9004,
ExifCompConfig = 0x9101,
ExifCompBPP = 0x9102,
ExifShutterSpeed = 0x9201,
ExifAperture = 0x9202,
ExifBrightness = 0x9203,
ExifExposureBias = 0x9204,
ExifMaxAperture = 0x9205,
ExifSubjectDist = 0x9206,
ExifMeteringMode = 0x9207,
ExifLightSource = 0x9208,
ExifFlash = 0x9209,
ExifFocalLength = 0x920A,
ExifMakerNote = 0x927C,
ExifUserComment = 0x9286,
ExifDTSubsec = 0x9290,
ExifDTOrigSS = 0x9291,
ExifDTDigSS = 0x9292,
ExifFPXVer = 0xA000,
ExifColorSpace = 0xA001,
ExifPixXDim = 0xA002,
ExifPixYDim = 0xA003,
ExifRelatedWav = 0xA004,
ExifInterop = 0xA005,
ExifFlashEnergy = 0xA20B,
ExifSpatialFR = 0xA20C,
ExifFocalXRes = 0xA20E,
ExifFocalYRes = 0xA20F,
ExifFocalResUnit = 0xA210,
ExifSubjectLoc = 0xA214,
ExifExposureIndex = 0xA215,
ExifSensingMethod = 0xA217,
ExifFileSource = 0xA300,
ExifSceneType = 0xA301,
ExifCfaPattern = 0xA302,
GpsVer = 0x0,
GpsLatitudeRef = 0x1,
GpsLatitude = 0x2,
GpsLongitudeRef = 0x3,
GpsLongitude = 0x4,
GpsAltitudeRef = 0x5,
GpsAltitude = 0x6,
GpsGpsTime = 0x7,
GpsGpsSatellites = 0x8,
GpsGpsStatus = 0x9,
GpsGpsMeasureMode = 0xA,
GpsGpsDop = 0xB,
GpsSpeedRef = 0xC,
GpsSpeed = 0xD,
GpsTrackRef = 0xE,
GpsTrack = 0xF,
GpsImgDirRef = 0x10,
GpsImgDir = 0x11,
GpsMapDatum = 0x12,
GpsDestLatRef = 0x13,
GpsDestLat = 0x14,
GpsDestLongRef = 0x15,
GpsDestLong = 0x16,
GpsDestBearRef = 0x17,
GpsDestBear = 0x18,
GpsDestDistRef = 0x19,
GpsDestDist = 0x1A
}


//
// Real position of 0th row and column of picture
//
//
//
// [altair] 10.09.2003 Created
//

public enum Orientations
{
TopLeft = 1,
TopRight = 2,
BottomRight = 3,
BottomLeft = 4,
LeftTop = 5,
RightTop = 6,
RightBottom = 7,
LftBottom = 8
}


//
// Exposure programs
//
//
//
// [altair] 10.09.2003 Created
//

public enum ExposurePrograms
{
Manual = 1,
Normal = 2,
AperturePriority = 3,
ShutterPriority = 4,
Creative = 5,
Action = 6,
Portrait = 7,
Landscape = 8,
}


//
// Exposure metering modes
//
//
//
// [altair] 10.09.2003 Created
//

public enum ExposureMeteringModes
{
Unknown = 0,
Average = 1,
CenterWeightedAverage = 2,
Spot = 3,
MultiSpot = 4,
MultiSegment = 5,
Partial = 6,
Other = 255
}


//
// Flash activity modes
//
//
//
// [altair] 10.09.2003 Created
//

public enum FlashModes
{
NotFired = 0,
Fired = 1,
FiredButNoStrobeReturned = 5,
FiredAndStrobeReturned = 7,
}


//
// Possible light sources (white balance)
//
//
//
// [altair] 10.09.2003 Created
//

public enum LightSources
{
Unknown = 0,
Daylight = 1,
Fluorescent = 2,
Tungsten = 3,
Flash = 10,
StandardLightA = 17,
StandardLightB = 18,
StandardLightC = 19,
D55 = 20,
D65 = 21,
D75 = 22,
Other = 255
}


//
// EXIF data types
//
//
//
// [altair] 12.6.2004 Created
//
public enum ExifDataTypes : short
{
UnsignedByte = 1,
AsciiString = 2,
UnsignedShort = 3,
UnsignedLong = 4,
UnsignedRational = 5,
SignedByte = 6,
Undefined = 7,
SignedShort = 8,
SignedLong = 9,
SignedRational = 10,
SingleFloat = 11,
DoubleFloat = 12
}


//
// Represents rational which is type of some Exif properties
//
//
//
// [altair] 10.09.2003 Created
//
public struct Rational
{
public Int32 Numerator;
public Int32 Denominator;


//
// Converts rational to string representation
//
// Optional, default "/". String to be used as delimiter of components.
// String representation of the rational.
//
//
// [altair] 10.09.2003 Created
//

public override string ToString()
{
return ToString("/");
}

public string ToString(string Delimiter)
{
return Numerator + "/" + Denominator;
}

//
// Converts rational to double precision real number
//
// The rational as double precision real number.
//
//
// [altair] 10.09.2003 Created
//

public double ToDouble()
{
return (double)Numerator / Denominator;
}
}

#endregion

//
// Initializes new instance of this class.
//
// Bitmap to read exif information from
//
//
// [altair] 10.09.2003 Created
//
public ExifManager(System.Drawing.Bitmap Bitmap)
{
if (Bitmap == null)
throw new ArgumentNullException("Bitmap");
this._Image = Bitmap;
}

//
// Initializes new instance of this class.
//
// Name of file to be loaded
//
//
// [altair] 13.06.2004 Created
//
public ExifManager(string FileName)
{
this._Image = (System.Drawing.Bitmap)System.Drawing.Bitmap.FromFile(FileName);
}

//
// Get or set encoding used for string metadata
//
// Encoding used for string metadata
// Default encoding is UTF-8
//
// [altair] 11.07.2004 Created
// [altair] 05.09.2005 Changed from shared to instance member
//
public System.Text.Encoding Encoding
{
get
{
return this._Encoding;
}
set
{
if (value == null)
throw new ArgumentNullException();
this._Encoding = value;
}
}

//
// Returns copy of bitmap this instance is working on
//
//
//
//
// [altair] 13.06.2004 Created
//
public System.Drawing.Bitmap GetBitmap()
{
return (System.Drawing.Bitmap)this._Image.Clone();
}

//
// Returns all available data in formatted string form
//
//
//
//
// [altair] 10.09.2003 Created
//
public override string ToString()
{
System.Text.StringBuilder SB = new StringBuilder();

SB.Append("照片信息:");
SB.Append("\n\t尺寸: " + this.Width + " x " + this.Height + " px");
SB.Append("\n\t分辨率: " + this.ResolutionX + " x " + this.ResolutionY + " dpi");
SB.Append("\n\t方向: " + Enum.GetName(typeof(Orientations), this.Orientation));
SB.Append("\n\t標題: " + this.Title);
SB.Append("\n\t描述: " + this.Description);
SB.Append("\n\t作者: " + this.Artist);
SB.Append("\n\t版權信息: " + this.Copyright);
SB.Append("\n相機信息:");
SB.Append("\n\t制造商: " + this.EquipmentMaker);
SB.Append("\n\t型號: " + this.EquipmentModel);
SB.Append("\n\t編輯軟件: " + this.Software);
SB.Append("\n時間信息:");
SB.Append("\n\t最后編輯時間: " + this.DateTimeLastModified.ToString());
SB.Append("\n\t原始拍照時間: " + this.DateTimeOriginal.ToString());
SB.Append("\n\t數字化時間: " + this.DateTimeDigitized.ToString());
SB.Append("\n拍攝信息:");
SB.Append("\n\t曝光時間: " + this.ExposureTime.ToString("N4") + " s");
SB.Append("\n\t曝光模式: " + Enum.GetName(typeof(ExposurePrograms), this.ExposureProgram));
SB.Append("\n\t測光模式: " + Enum.GetName(typeof(ExposureMeteringModes), this.ExposureMeteringMode));
SB.Append("\n\t光圈值: F" + this.Aperture.ToString("N1"));
SB.Append("\n\tISO感光度: " + this.ISO);
SB.Append("\n\t拍攝距離: " + this.SubjectDistance.ToString("N2") + " m");
SB.Append("\n\t焦距: " + this.FocalLength + " mm");
SB.Append("\n\t閃光燈: " + Enum.GetName(typeof(FlashModes), this.FlashMode));
SB.Append("\n\t白平衡(WB): " + Enum.GetName(typeof(LightSources), this.LightSource));
//SB.Replace("\n", vbCrLf);
//SB.Replace("\t", vbTab);
return SB.ToString();
}

#region Nicely formatted well-known properties

//
// Brand of equipment (EXIF EquipMake)
//
//
//
//
// [altair] 10.09.2003 Created
//
public string EquipmentMaker
{
get
{
return this.GetPropertyString((int)TagNames.EquipMake);
}
}

//
// Model of equipment (EXIF EquipModel)
//
//
//
//
// [altair] 10.09.2003 Created
//
public string EquipmentModel
{
get
{
return this.GetPropertyString((int)TagNames.EquipModel);
}
}

//
// Software used for processing (EXIF Software)
//
//
//
//
// [altair] 10.09.2003 Created
//
public string Software
{
get
{
return this.GetPropertyString((int)TagNames.SoftwareUsed);
}
}

//
// Orientation of image (position of row 0, column 0) (EXIF Orientation)
//
//
//
//
// [altair] 10.09.2003 Created
//
public Orientations Orientation
{
get
{
Int32 X = this.GetPropertyInt16((int)TagNames.Orientation);

if (!Enum.IsDefined(typeof(Orientations), X))
return Orientations.TopLeft;
else
return (Orientations)Enum.Parse(typeof(Orientations), Enum.GetName(typeof(Orientations), X));
}
}

//
// Time when image was last modified (EXIF DateTime).
//
//
//
//
// [altair] 10.09.2003 Created
//
public DateTime DateTimeLastModified
{
get
{
try
{
return DateTime.ParseExact(this.GetPropertyString((int)TagNames.DateTime), @"yyyy\:MM\:dd HH\:mm\:ss", null);
}
catch
{
return DateTime.MinValue;
}
}
set
{
try
{
this.SetPropertyString((int)TagNames.DateTime, value.ToString(@"yyyy\:MM\:dd HH\:mm\:ss"));
}
catch
{ }
}
}

//
// Time when image was taken (EXIF DateTimeOriginal).
//
//
//
//
// [altair] 10.09.2003 Created
//
public DateTime DateTimeOriginal
{
get
{
try
{
return DateTime.ParseExact(this.GetPropertyString((int)TagNames.ExifDTOrig), @"yyyy\:MM\:dd HH\:mm\:ss", null);
}
catch
{
return DateTime.MinValue;
}
}
set
{
try
{
this.SetPropertyString((int)TagNames.ExifDTOrig, value.ToString(@"yyyy\:MM\:dd HH\:mm\:ss"));
}
catch
{ }
}
}

//
// Time when image was digitized (EXIF DateTimeDigitized).
//
//
//
//
// [altair] 10.09.2003 Created
//
public DateTime DateTimeDigitized
{
get
{
try
{
return DateTime.ParseExact(this.GetPropertyString((int)TagNames.ExifDTDigitized), @"yyyy\:MM\:dd HH\:mm\:ss", null);
}
catch
{
return DateTime.MinValue;
}
}
set
{
try
{
this.SetPropertyString((int)TagNames.ExifDTDigitized, value.ToString(@"yyyy\:MM\:dd HH\:mm\:ss"));
}
catch
{ }
}
}

//
// Image width
//
//
//
//
// [altair] 10.09.2003 Created
// [altair] 04.09.2005 Changed output to Int32, load from image instead of EXIF
//
public Int32 Width
{
get { return this._Image.Width; }
}

//
// Image height
//
//
//
//
// [altair] 10.09.2003 Created
// [altair] 04.09.2005 Changed output to Int32, load from image instead of EXIF
//
public Int32 Height
{
get { return this._Image.Height; }
}

//
// X resolution in dpi (EXIF XResolution/ResolutionUnit)
//
//
//
//
// [altair] 10.09.2003 Created
//
public double ResolutionX
{
get
{
double R = this.GetPropertyRational((int)TagNames.XResolution).ToDouble();

if (this.GetPropertyInt16((int)TagNames.ResolutionUnit) == 3)
{
// -- resolution is in points/cm
return R * 2.54;
}
else
{
// -- resolution is in points/inch
return R;
}
}
}

//
// Y resolution in dpi (EXIF YResolution/ResolutionUnit)
//
//
//
//
// [altair] 10.09.2003 Created
//
public double ResolutionY
{
get
{
double R = this.GetPropertyRational((int)TagNames.YResolution).ToDouble();

if (this.GetPropertyInt16((int)TagNames.ResolutionUnit) == 3)
{
// -- resolution is in points/cm
return R * 2.54;
}
else
{
// -- resolution is in points/inch
return R;
}
}
}

//
// Image title (EXIF ImageTitle)
//
//
//
//
// [altair] 10.09.2003 Created
//
public string Title
{
get
{
return this.GetPropertyString((int)TagNames.ImageTitle);
}
set
{
try
{
this.SetPropertyString((int)TagNames.ImageTitle, value);
}
catch { }
}
}

//
// User comment (EXIF UserComment)
//
//
//
//
// [altair] 13.06.2004 Created
//
public string UserComment
{
get
{
return this.GetPropertyString((int)TagNames.ExifUserComment);
}
set
{
try
{
this.SetPropertyString((int)TagNames.ExifUserComment, value);
}
catch { }
}
}

//
// Artist name (EXIF Artist)
//
//
//
//
// [altair] 13.06.2004 Created
//
public string Artist
{
get
{
return this.GetPropertyString((int)TagNames.Artist);
}
set
{
try
{
this.SetPropertyString((int)TagNames.Artist, value);
}
catch { }
}
}

//
// Image description (EXIF ImageDescription)
//
//
//
//
// [altair] 10.09.2003 Created
//
public string Description
{
get
{
return this.GetPropertyString((int)TagNames.ImageDescription);
}
set
{
try
{
this.SetPropertyString((int)TagNames.ImageDescription, value);
}
catch { }
}
}

//
// Image copyright (EXIF Copyright)
//
//
//
//
// [altair] 10.09.2003 Created
//
public string Copyright
{
get
{
return this.GetPropertyString((int)TagNames.Copyright);
}
set
{
try
{
this.SetPropertyString((int)TagNames.Copyright, value);
}
catch { }
}
}


//
// Exposure time in seconds (EXIF ExifExposureTime/ExifShutterSpeed)
//
//
//
//
// [altair] 10.09.2003 Created
//
public double ExposureTimeAbs
{
get
{
if (this.IsPropertyDefined((int)TagNames.ExifExposureTime))
// -- Exposure time is explicitly specified
return this.GetPropertyRational((int)TagNames.ExifExposureTime).ToDouble();
else
if (this.IsPropertyDefined((int)TagNames.ExifShutterSpeed))
//'-- Compute exposure time from shutter spee
return (1 / Math.Pow(2, this.GetPropertyRational((int)TagNames.ExifShutterSpeed).ToDouble()));
else
// -- Can't figure out
return 0;
}
}

public Rational ExposureTime
{
get
{
if (this.IsPropertyDefined((int)TagNames.ExifExposureTime))
// -- Exposure time is explicitly specified
return this.GetPropertyRational((int)TagNames.ExifExposureTime);
else
return new Rational();
}
}

//
// Aperture value as F number (EXIF ExifFNumber/ExifApertureValue)
//
//
//
//
// [altair] 10.09.2003 Created
//
public double Aperture
{
get
{
if (this.IsPropertyDefined((int)TagNames.ExifFNumber))
return this.GetPropertyRational((int)TagNames.ExifFNumber).ToDouble();
else
if (this.IsPropertyDefined((int)TagNames.ExifAperture))
return Math.Pow(System.Math.Sqrt(2), this.GetPropertyRational((int)TagNames.ExifAperture).ToDouble());
else
return 0;
}
}

//
// Exposure program used (EXIF ExifExposureProg)
//
//
// If not specified, returns Normal (2)
//
// [altair] 10.09.2003 Created
//
public ExposurePrograms ExposureProgram
{
get
{
Int32 X = this.GetPropertyInt16((int)TagNames.ExifExposureProg);

if (Enum.IsDefined(typeof(ExposurePrograms), X))
return (ExposurePrograms)Enum.Parse(typeof(ExposurePrograms), Enum.GetName(typeof(ExposurePrograms), X));
else
return ExposurePrograms.Normal;
}
}

//
// ISO sensitivity
//
//
//
//
// [altair] 10.09.2003 Created
//
public Int16 ISO
{
get { return this.GetPropertyInt16((int)TagNames.ExifISOSpeed); }
}

//
// Subject distance in meters (EXIF SubjectDistance)
//
//
//
//
// [altair] 10.09.2003 Created
//
public double SubjectDistance
{
get { return this.GetPropertyRational((int)TagNames.ExifSubjectDist).ToDouble(); }
}

//
// Exposure method metering mode used (EXIF MeteringMode)
//
//
// If not specified, returns Unknown (0)
//
// [altair] 10.09.2003 Created
//
public ExposureMeteringModes ExposureMeteringMode
{
get
{
Int32 X = this.GetPropertyInt16((int)TagNames.ExifMeteringMode);

if (Enum.IsDefined(typeof(ExposureMeteringModes), X))
return (ExposureMeteringModes)Enum.Parse(typeof(ExposureMeteringModes), Enum.GetName(typeof(ExposureMeteringModes), X));
else
return ExposureMeteringModes.Unknown;
}
}

//
// Focal length of lenses in mm (EXIF FocalLength)
//
//
//
//
// [altair] 10.09.2003 Created
//
public double FocalLength
{
get { return this.GetPropertyRational((int)TagNames.ExifFocalLength).ToDouble(); }
}

//
// Flash mode (EXIF Flash)
//
//
// If not present, value NotFired (0) is returned
//
// [altair] 10.09.2003 Created
//
public FlashModes FlashMode
{
get
{
Int32 X = this.GetPropertyInt16((int)TagNames.ExifFlash);

if (Enum.IsDefined(typeof(FlashModes), X))
return (FlashModes)Enum.Parse(typeof(FlashModes), Enum.GetName(typeof(FlashModes), X));
else
return FlashModes.NotFired;
}
}

//
// Light source / white balance (EXIF LightSource)
//
//
// If not specified, returns Unknown (0).
//
// [altair] 10.09.2003 Created
//
public LightSources LightSource
{
get
{
Int32 X = this.GetPropertyInt16((int)TagNames.ExifLightSource);

if (Enum.IsDefined(typeof(LightSources), X))
return (LightSources)Enum.Parse(typeof(LightSources), Enum.GetName(typeof(LightSources), X));
else
return LightSources.Unknown;
}
}

#endregion

#region Support methods for working with EXIF properties

//
// Checks if current image has specified certain property
//
//
// True if image has specified property, False otherwise.
//
//
// [altair] 10.09.2003 Created
//
public bool IsPropertyDefined(Int32 PID)
{
return (Array.IndexOf(this._Image.PropertyIdList, PID) > -1);
}

//
// Gets specified Int32 property
//
// Property ID
// Optional, default 0. Default value returned if property is not present.
// Value of property or DefaultValue if property is not present.
//
//
// [altair] 10.09.2003 Created
//
public Int32 GetPropertyInt32(Int32 PID)
{
return GetPropertyInt32(PID, 0);
}

public Int32 GetPropertyInt32(Int32 PID, Int32 DefaultValue)
{
if (IsPropertyDefined(PID))
return GetInt32(this._Image.GetPropertyItem(PID).Value);
else
return DefaultValue;
}

//
// Gets specified Int16 property
//
// Property ID
// Optional, default 0. Default value returned if property is not present.
// Value of property or DefaultValue if property is not present.
//
//
// [altair] 10.09.2003 Created
//
public Int16 GetPropertyInt16(Int32 PID)
{
return GetPropertyInt16(PID, 0);
}

public Int16 GetPropertyInt16(Int32 PID, Int16 DefaultValue)
{
if (IsPropertyDefined(PID))
return GetInt16(this._Image.GetPropertyItem(PID).Value);
else
return DefaultValue;
}

//
// Gets specified string property
//
// Property ID
// Optional, default String.Empty. Default value returned if property is not present.
//
// Value of property or DefaultValue if property is not present.
//
// [altair] 10.09.2003 Created
//
public string GetPropertyString(Int32 PID)
{
return GetPropertyString(PID, "");
}

public string GetPropertyString(Int32 PID, string DefaultValue)
{
if (IsPropertyDefined(PID))
return GetString(this._Image.GetPropertyItem(PID).Value);
else
return DefaultValue;
}

//
// Gets specified property in raw form
//
// Property ID
// Optional, default Nothing. Default value returned if property is not present.
//
// Is recommended to use typed methods (like etc.) instead, when possible.
//
// [altair] 05.09.2005 Created
//
public byte[] GetProperty(Int32 PID, byte[] DefaultValue)
{
if (IsPropertyDefined(PID))
return this._Image.GetPropertyItem(PID).Value;
else
return DefaultValue;
}

public byte[] GetProperty(Int32 PID)
{
return GetProperty(PID, null);
}

//
// Gets specified rational property
//
// Property ID
//
// Value of property or 0/1 if not present.
//
// [altair] 10.09.2003 Created
//
public Rational GetPropertyRational(Int32 PID)
{
if (IsPropertyDefined(PID))
return GetRational(this._Image.GetPropertyItem(PID).Value);
else
{
Rational R;
R.Numerator = 0;
R.Denominator = 1;
return R;
}
}

//
// Sets specified string property
//
// Property ID
// Value to be set
//
//
// [altair] 12.6.2004 Created
//
public void SetPropertyString(Int32 PID, string Value)
{
byte[] Data = this._Encoding.GetBytes(Value + '\0');
SetProperty(PID, Data, ExifDataTypes.AsciiString);
}

//
// Sets specified Int16 property
//
// Property ID
// Value to be set
//
//
// [altair] 12.6.2004 Created
//
public void SetPropertyInt16(Int32 PID, Int16 Value)
{
byte[] Data = new byte[2];
Data[0] = (byte)(Value & 0xFF);
Data[1] = (byte)((Value & 0xFF00) >> 8);
SetProperty(PID, Data, ExifDataTypes.SignedShort);
}

//
// Sets specified Int32 property
//
// Property ID
// Value to be set
//
//
// [altair] 13.06.2004 Created
//
public void SetPropertyInt32(Int32 PID, Int32 Value)
{
byte[] Data = new byte[4];
for (int I = 0; I < 4; I++)
{
Data[I] = (byte)(Value & 0xFF);
Value >>= 8;
}
SetProperty(PID, Data, ExifDataTypes.SignedLong);
}

//
// Sets specified property in raw form
//
// Property ID淘寶網女裝夏裝新款
// Raw data
// EXIF data type
// Is recommended to use typed methods (like etc.) instead, when possible.
//
// [altair] 12.6.2004 Created
//
public void SetProperty(Int32 PID, byte[] Data, ExifDataTypes Type)
{
System.Drawing.Imaging.PropertyItem P = this._Image.PropertyItems[0];
P.Id = PID;
P.Value = Data;
P.Type = (Int16)Type;
P.Len = Data.Length;
this._Image.SetPropertyItem(P);
}

//
// Reads Int32 from EXIF bytearray.
//
// EXIF bytearray to process
//
//
//
// [altair] 10.09.2003 Created
// [altair] 05.09.2005 Changed from public shared to private instance method
//
private Int32 GetInt32(byte[] B)
{
if (B.Length < 4)
throw new ArgumentException("Data too short (4 bytes expected)", "B");

return B[3] << 24 | B[2] << 16 | B[1] << 8 | B[0];
}

//
// Reads Int16 from EXIF bytearray.
//
// EXIF bytearray to process
//
//
//
// [altair] 10.09.2003 Created
// [altair] 05.09.2005 Changed from public shared to private instance method
//
private Int16 GetInt16(byte[] B)
{
if (B.Length < 2)
throw new ArgumentException("Data too short (2 bytes expected)", "B");

return (short)(B[1] << 8 | B[0]);
}

//
// Reads string from EXIF bytearray.
//
// EXIF bytearray to process
//
//
//
// [altair] 10.09.2003 Created
// [altair] 05.09.2005 Changed from public shared to private instance method
//
private string GetString(byte[] B)
{
string R = this._Encoding.GetString(B);
if (R.EndsWith("\0"))
R = R.Substring(0, R.Length - 1);
return R;
}

//
// Reads rational from EXIF bytearray.
//
// EXIF bytearray to process
//
//
//
// [altair] 10.09.2003 Created
// [altair] 05.09.2005 Changed from public shared to private instance method
//
private Rational GetRational(byte[] B)
{
Rational R = new Rational();
byte[] N = new byte[4];
byte[] D = new byte[4];
Array.Copy(B, 0, N, 0, 4);
Array.Copy(B, 4, D, 0, 4);
R.Denominator = this.GetInt32(D);
R.Numerator = this.GetInt32(N);
return R;
}

public void Save(string fileName){
    this._Image.Save(fileName);
}
#endregion

#region " IDisposable implementation "

//
// Disposes unmanaged resources of this class
//
//
//
// [altair] 10.09.2003 Created
//
public void Dispose()
{
this._Image.Dispose();
}

#endregion

}
}