Develop Reference

Word Interop - Save embedded shape as image

I am attempting to save an embedded shape as an image using C#.
If the object is embedded as an actual image (WMF/JPEG) I can retrieve the image without issue but when the object is an embedded shape or an OLE Object that displays as an image in Word I cannot seem to extract or retrieve said object to then either copy to the clipboard or save said image.
Here is my current code sample; either the object is empty or I get the following error:
System.Runtime.InteropServices.ExternalException: 'A generic error occurred in GDI+.'
Any help is appreciated. Thank you
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Forms;
using System.Windows.Media;
using System.Windows.Media.Imaging;
namespace ImageMagickSandboxWinForms
{
public partial class frmMain : Form
{
public frmMain()
{
InitializeComponent();
}
public static BitmapSource ConvertBitmap(Bitmap source)
{
return System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
source.GetHbitmap(),
IntPtr.Zero,
Int32Rect.Empty,
BitmapSizeOptions.FromEmptyOptions());
}
public static Bitmap BitmapFromSource(BitmapSource bitmapsource)
{
Bitmap bitmap;
using (var outStream = new MemoryStream())
{
BitmapEncoder enc = new BmpBitmapEncoder();
enc.Frames.Add(BitmapFrame.Create(bitmapsource));
enc.Save(outStream);
bitmap = new Bitmap(outStream);
}
return bitmap;
}
private void button1_Click(object sender, EventArgs e)
{
string physicsDocLocation = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop));
physicsDocLocation += #"\[Doc path Here].docx";
var wordApp = new Microsoft.Office.Interop.Word.Application();
var wordDoc = wordApp.Documents.Open(physicsDocLocation);
int iCount = wordDoc.InlineShapes.Count;
for (int i = 1; i < (wordDoc.InlineShapes.Count + 1); i++)
{
var currentInlineShape = wordDoc.InlineShapes[i];
currentInlineShape.Range.Select();
wordDoc.ActiveWindow.Selection.Range.Copy();
BitmapSource clipBoardImage = System.Windows.Clipboard.GetImage();
Bitmap bmpClipImage = BitmapFromSource(clipBoardImage);
string finalPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), #"TestConversions");
finalPath += #"\" + Guid.NewGuid().ToString() + ".jpg";
using (MemoryStream memory = new MemoryStream())
{
using (FileStream fs = new FileStream(finalPath, FileMode.Create, FileAccess.ReadWrite))
{
bmpClipImage.Save(memory, ImageFormat.Jpeg); <<<---- Error happens here.
byte[] bytes = memory.ToArray();
fs.Write(bytes, 0, bytes.Length);
}
}
}
wordDoc.Close();
wordApp.Quit();
}
}
}

i have these code in my library, dunno where i have found that but hope you do the job for you: i am using Clippboard to trap the different images, jus t dont forget, Thread is needed to access Clipboard
for (var i = 1; i <= wordApplication.ActiveDocument.InlineShapes.Count; i++)
{
var inlineShapeId = i;
var thread = new Thread(() => SaveInlineShapeToFile(inlineShapeId, wordApplication));
// STA is needed in order to access the clipboard
// https://stackoverflow.com/a/518724/700926
thread.SetApartmentState(ApartmentState.STA);
thread.Start();
thread.Join();
}
// General idea is based on: https://stackoverflow.com/a/7937590/700926
protected static void SaveInlineShapeToFile(int inlineShapeId, Application wordApplication)
{
// Get the shape, select, and copy it to the clipboard
var inlineShape = wordApplication.ActiveDocument.InlineShapes[inlineShapeId];
inlineShape.Select();
wordApplication.Selection.Copy();
// Check data is in the clipboard
if (Clipboard.GetDataObject() != null)
{
var data = Clipboard.GetDataObject();
// Check if the data conforms to a bitmap format
if (data != null && data.GetDataPresent(DataFormats.Bitmap))
{
// Fetch the image and convert it to a Bitmap
var image = (Image) data.GetData(DataFormats.Bitmap, true);
var currentBitmap = new Bitmap(image);
// Save the bitmap to a file
currentBitmap.Save(#"C:\Users\Username\Documents\" + String.Format("img_{0}.png", inlineShapeId));
}
}
}
following if you are using Winform or WPF the clipboard acts differently for an image:
if (Clipboard.ContainsImage())
{
// ImageUIElement.Source = Clipboard.GetImage(); // does not work
System.Windows.Forms.IDataObject clipboardData = System.Windows.Forms.Clipboard.GetDataObject();
if (clipboardData != null)
{
if (clipboardData.GetDataPresent(System.Windows.Forms.DataFormats.Bitmap))
{
System.Drawing.Bitmap bitmap = (System.Drawing.Bitmap)clipboardData.GetData(System.Windows.Forms.DataFormats.Bitmap);
ImageUIElement.Source = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(bitmap.GetHbitmap(), IntPtr.Zero, Int32Rect.Empty,BitmapSizeOptions.FromEmptyOptions());
Console.WriteLine("Clipboard copied to UIElement");
}
}
}
after if its not functionam due to a bug in translation of format, there is this solution . So its infrecnh but its easily to understand the logic of the using of "DeviceIndependentBitmap"

Convert Tiff to pdf with PDFSharp-gdi C#

I am stuck. Currently I am trying to simulate pulling a binary blob from a database that is supposed to be a TIFF image. I use this gist image.tif in the image variable to do so. I am pretty sure I am close to making this happen. It's that the issue probably has to do with how I am converting the string to byte array or something. Basically this application throws an exception stating that it can't create a PDF with 0 frames. At this point I must admit that I may be in over my head on this one. Could someone be so kind and help me the rest of the way with this one?
The code is included below:
using System;
using System.Drawing;
using PdfSharp.Pdf;
using PdfSharp.Drawing;
using System.IO;
using System.Drawing.Imaging;
using System.Text;
namespace ConvertTifToPDFFile
{
class Program
{
static void Main(string[] args)
{
string image = "";
byte[] imageAsByteStream = Encoding.ASCII.GetBytes(image);
int imageByteStreamLength = imageAsByteStream.Length;
string base64EncodedImage = Convert.ToBase64String(imageAsByteStream);
imageAsByteStream = Encoding.ASCII.GetBytes(base64EncodedImage);
Stream imageStream = TiffImageSplitter.ByteArrayToMemoryStream(imageAsByteStream);
// Image splitImage = TiffImageSplitter.getTiffImage(imageStream, 1);
TiffImageSplitter.tiff2PDF(imageStream);
}
}
public class TiffImageSplitter
{
private static TiffImageSplitter tiff = new TiffImageSplitter();
public static void tiff2PDF(Stream imageByteStream)
{
PdfDocument doc = new PdfDocument();
int pageCount = getPageCount(imageByteStream);
for (int i = 0; i < pageCount; i++)
{
PdfPage page = new PdfPage();
Image img = getTiffImage(imageByteStream, 1);
XImage imgFrame = XImage.FromGdiPlusImage(img);
page.Width = imgFrame.PointWidth;
page.Height = imgFrame.PointHeight;
doc.Pages.Add(page);
XGraphics xgr = XGraphics.FromPdfPage(doc.Pages[i]);
xgr.DrawImage(img, 0, 0);
}
doc.Save("C:/temp/test.pdf");
doc.Close();
}
public static Image getTiffImage(Stream imageStream, int pageNumber)
{
MemoryStream ms = null;
Image returnImage = null;
try
{
ms = new MemoryStream();
Image sourceImage = Image.FromStream(imageStream, true, true);
Guid objGuid = sourceImage.FrameDimensionsList[0];
FrameDimension objDimension = new FrameDimension(objGuid);
sourceImage.SelectActiveFrame(objDimension, pageNumber);
sourceImage.Save(ms, ImageFormat.Tiff);
returnImage = Image.FromStream(ms);
}
catch (Exception ex)
{
Console.WriteLine("{0} Exception caught.", ex);
returnImage = null;
}
return returnImage;
}
public static MemoryStream ByteArrayToMemoryStream(byte[] bytestream)
{
MemoryStream stream = new MemoryStream();
stream.Write(bytestream, 0, bytestream.Length);
return stream;
}
public static int getPageCount(Stream imageStream)
{
int pageCount = -1;
try
{
Image img = Image.FromStream(imageStream, true, true);
pageCount = img.GetFrameCount(FrameDimension.Page);
img.Dispose();
}
catch (Exception ex)
{
Console.WriteLine("{0} Exception caught.", ex);
pageCount = 0;
}
return pageCount;
}
}
}

IMPORTANT!!!! First of all, your example tiff isn't valid at all. It can't be read by any file editor. I have had to take these ones for testing.
Then, the code has couple errors:
1) I don't understand what've done with strings but reading files and BLOBs are same:
static void Main(string[] args)
{
//string image = "";
//byte[] imageAsByteStream = Encoding.ASCII.GetBytes(image);
byte[] imageAsByteStream = File.ReadAllBytes("../../../MARBIBM.TIF");
//int imageByteStreamLength = imageAsByteStream.Length;
//string base64EncodedImage = Convert.ToBase64String(imageAsByteStream);
//imageAsByteStream = Encoding.ASCII.GetBytes(base64EncodedImage);
Stream imageStream = TiffImageSplitter.ByteArrayToMemoryStream(imageAsByteStream);
// Image splitImage = TiffImageSplitter.getTiffImage(imageStream, 1);
TiffImageSplitter.tiff2PDF(imageStream);
}
2) method tiff2PDF should be like that
public static void tiff2PDF(Stream imageByteStream)
{
PdfDocument doc = new PdfDocument();
int pageCount = getPageCount(imageByteStream);
for (int i = 0; i < pageCount; i++)
{
PdfPage page = new PdfPage();
Image img = getTiffImage(imageByteStream, i); //<---HERE WAS ANOTHER ERROR, LOOK AT i
XImage imgFrame = XImage.FromGdiPlusImage(img);
3)
public static MemoryStream ByteArrayToMemoryStream(byte[] bytestream)
{
MemoryStream stream = new MemoryStream(bytestream);
//stream.Write(bytestream, 0, bytestream.Length);
return stream;
}

Edit png metadata, add itxt value

I am trying to create a function that will load a PNG from a URL into memory and then add an iTXt chunk with the keyword "openbadges" and some json data. I have every part working except when I execute
metadata.SetQuery("/iTXt/openbadges", "");
I get an exception:
Value does not fall within the expected range.
Here is the function:
private static byte[] CreateOpenBadge(BadgeAssertionEntity assertion)
{
using (var image = LoadImage(new Uri(assertion.Badge.ImageUrl)))
using (var imageStream = new MemoryStream())
{
image.Save(imageStream, ImageFormat.Png);
var pngDecoder = new PngBitmapDecoder(imageStream, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default);
using (var badgeStream = new MemoryStream())
{
var pngEncoder = new PngBitmapEncoder();
pngEncoder.Frames.Add(BitmapFrame.Create(pngDecoder.Frames[0]));
var metadata = pngEncoder.Frames[0].Metadata as BitmapMetadata;
if (metadata == null)
throw new ApplicationException();
metadata.SetQuery("/iTXt/openbadges", "");
pngEncoder.Save(badgeStream);
return badgeStream.ToArray();
}
}
}
Any ideas what I am doing wrong?

The trick is to setquery() "/iTXt/Keyword" and "/iTXt/TextEntry", but you must use a char[] for the value of Keyword.
This is because internally "/iTXt/Keyword" wants a VT_LPSTR as the value type, and only a char[] will correctly convert into that.
Here's a sample that uses WIC to write a checkerboard png, including some iTXt metadata.
using System.IO;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Imaging;
namespace PNGEncoder
{
class Program
{
static void Main(string[] args)
{
var width = 256;
var height = 256;
var pngMetadata = new BitmapMetadata("png");
pngMetadata.SetQuery("/iTXt/Keyword", "keyword0".ToCharArray());
pngMetadata.SetQuery("/iTXt/TextEntry", "textentry0");
pngMetadata.SetQuery("/[1]iTXt/Keyword", "keyword1".ToCharArray());
pngMetadata.SetQuery("/[1]iTXt/TextEntry", "textentry1");
var bitmap = new WriteableBitmap(width, height, 96, 96, PixelFormats.Gray8, null);
var pixels = new byte[width * height];
for (var y = 0; y < height; y++)
{
for (var x = 0; x < width; x++)
{
pixels[y * width + x] = (byte)(255 * (((x >> 4) ^ (y >> 4)) & 1));
}
}
bitmap.WritePixels(new Int32Rect(0, 0, width, height), pixels, width, 0);
var encoder = new PngBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(bitmap, null, pngMetadata, null));
using (var stream = File.Create("checkerBoard.png"))
{
encoder.Save(stream);
}
}
}
}

I gave up on using PngBitmapEncoder. Instead I will just modify the png bytes directly. I have attached a class I made for this purpose incase others find it useful.
This class is heavily inspired by AShelly's response at Using Chunks in a PNG
I also use http://damieng.com/blog/2006/08/08/calculating_crc32_in_c_and_net for the crc hash.
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using Badger.Libraries.Hashing;
namespace Badger.Libraries.Images
{
public class Png
{
private readonly byte[] _header;
private readonly IList<Chunk> _chunks;
public Png(Uri imageUri)
{
_header = new byte[8];
_chunks = new List<Chunk>();
var webResponse = WebRequest.Create(imageUri).GetResponse();
using (var webResponseStream = webResponse.GetResponseStream())
using (var memoryStream = new MemoryStream())
{
if (webResponseStream == null)
throw new ArgumentException("invalid uri");
webResponseStream.CopyTo(memoryStream);
memoryStream.Seek(0, SeekOrigin.Begin);
memoryStream.Read(_header, 0, _header.Length);
while (memoryStream.Position < memoryStream.Length)
_chunks.Add(ChunkFromStream(memoryStream));
memoryStream.Close();
}
}
public void AddInternationalText(string keyword, string text)
{
// 1-79 (keyword)
// 1 (null character)
// 1 (compression flag)
// 1 (compression method)
// 0+ (language)
// 1 (null character)
// 0+ (translated keyword)
// 1 (null character)
// 0+ (text)
var typeBytes = Encoding.UTF8.GetBytes("iTXt");
var keywordBytes = Encoding.UTF8.GetBytes(keyword);
var textBytes = Encoding.UTF8.GetBytes(text);
var nullByte = BitConverter.GetBytes('\0')[0];
var zeroByte = BitConverter.GetBytes(0)[0];
var data = new List<byte>();
data.AddRange(keywordBytes);
data.Add(nullByte);
data.Add(zeroByte);
data.Add(zeroByte);
data.Add(nullByte);
data.Add(nullByte);
data.AddRange(textBytes);
var chunk = new Chunk(typeBytes, data.ToArray());
_chunks.Insert(1, chunk);
}
public byte[] ToBytes()
{
using (var stream = new MemoryStream())
{
stream.Write(_header, 0, _header.Length);
foreach (var chunk in _chunks)
chunk.WriteToStream(stream);
var bytes = stream.ToArray();
stream.Close();
return bytes;
}
}
private static Chunk ChunkFromStream(Stream stream)
{
var length = ReadBytes(stream, 4);
var type = ReadBytes(stream, 4);
var data = ReadBytes(stream, Convert.ToInt32(BitConverter.ToUInt32(length.Reverse().ToArray(), 0)));
stream.Seek(4, SeekOrigin.Current);
return new Chunk(type, data);
}
private static byte[] ReadBytes(Stream stream, int n)
{
var buffer = new byte[n];
stream.Read(buffer, 0, n);
return buffer;
}
private static void WriteBytes(Stream stream, byte[] bytes)
{
stream.Write(bytes, 0, bytes.Length);
}
private class Chunk
{
public Chunk(byte[] type, byte[] data)
{
_type = type;
_data = data;
}
public void WriteToStream(Stream stream)
{
WriteBytes(stream, BitConverter.GetBytes(Convert.ToUInt32(_data.Length)).Reverse().ToArray());
WriteBytes(stream, _type);
WriteBytes(stream, _data);
WriteBytes(stream, CalculateCrc(_type, _data));
}
private static byte[] CalculateCrc(IEnumerable<byte> type, IEnumerable<byte> data)
{
var bytes = new List<byte>();
bytes.AddRange(type);
bytes.AddRange(data);
var hasher = new Crc32();
using (var stream = new MemoryStream(bytes.ToArray()))
return hasher.ComputeHash(stream);
}
private readonly byte[] _type;
private readonly byte[] _data;
}
}
}

Can't retrieve image from SQL Server using Generic Handler c#

Whenever I retrieve an image using my Generic Handler, I retrieve either an empty image or a broken image.
Here is my code.
aspx File:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
//imports
using DHELTASSys.Modules;
using System.Data;
using DHELTASSys.AuditTrail;
namespace DHELTASSys
{
public partial class EvaluateOffense : System.Web.UI.Page
{
DisciplineModuleBL discipline = new DisciplineModuleBL();
DHELTASSysAuditTrail audit = new DHELTASSysAuditTrail();
protected void Page_Load(object sender, EventArgs e)
{
string position = Session["Position"].ToString();
if (Session["EmployeeID"] == null)
{
Response.Redirect("LogIn.aspx");
} else if(position != "HR Manager")
{
Response.Redirect("AccessDenied.aspx");
}
discipline.Offense_emp_id = int.Parse(Session["OffenseID"].ToString());
DataTable dt = discipline.GetProof();
if (dt.Rows == null)
{
Label9.Visible = false;
Image1.Visible = false;
}
}
protected void btnEvaluate_Click(object sender, EventArgs e)
{
discipline.Offense_emp_id = int.Parse(Session["OffenseID"].ToString());
discipline.Decision = drpDecision.Text;
discipline.AddOffenseDecision();
audit.Emp_id = int.Parse(Session["EmployeeID"].ToString());
audit.AddAuditTrail(drpDecision.Text + "ed Employee's offense.");
}
}
}
Here is the handler:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
//imports
using System.Data;
using DHELTASSys.Modules;
using DHELTASSys.DataAccess;
namespace DHELTASSys
{
public class ShowImage : IHttpHandler, System.Web.SessionState.IRequiresSessionState
{
DisciplineModuleBL discipline = new DisciplineModuleBL();
public void ProcessRequest(HttpContext context)
{
if (context.Session["OffenseID"].ToString() == null) return;
int offense_emp_id = int.Parse(context.Session["OffenseID"].ToString());
discipline.Offense_emp_id = offense_emp_id;
DataTable dt = discipline.GetProof();
if (dt.Rows == null) return;
int id = 1;
string image = dt.Rows[0][1].ToString() + id;
string FileName = dt.Rows[0][0].ToString();
string FileContentType = dt.Rows[0][2].ToString();
Byte[] bytes = (Byte[])dt.Rows[0][1];
string imageBase64 = Convert.ToBase64String(bytes);
context.Response.ContentType = "image/" + FileContentType;
if (context.Request.QueryString["id"] == "1")
{
MemoryStream ms = new MemoryStream();
ms.Write(bytes, 0, bytes.Length);
context.Response.Buffer = true;
System.Drawing.Image imagen = System.Drawing.Image.FromStream(ms);
context.Response.BinaryWrite(bytes);
ms.Dispose();
}
else
{
return;
}
}
public bool IsReusable
{
get
{
return true;
}
}
}
}
And adding to that, here is my image object.
<asp:Image ID="Image1" runat="server" ImageUrl="~/ShowImage.ashx" />
I already tweaked my code in so many ways.
The image file is stored in SQL Server using the data type "Image"
As you can see, I'm using the session to retrieve the specified image from the Database.
I have no problem in accessing the session whatsoever.
Thanks in advance.

Your code seems a bit more complicated than necessary; you can write the binary data to the outputstream without needing to load it into a memory stream, and you're doing nothing with your System.Drawing.Image object. Try this:
context.Response.OutputStream.Write(bytes, 0, bytes.Length);

First, I don't see anything wrong with the way you are writing the image to the response stream. There's a few useless lines of code but I understand that as you said, you were tweaking your code in desperation. Basically, this should be good enough...
Byte[] bytes = (Byte[])dt.Rows[0][1];
context.Response.ContentType = "image/" + FileContentType;
if (context.Request.QueryString["id"] == "1")
{
context.Response.BinaryWrite(bytes);
context.ApplicationInstance.CompleteRequest(); //just to make sure the ASP.NET pipeline completes the request
}
else
{
return;
}
Now, that "should" work given that bytes has been correctly casted to a byte array. Make sure to add some proper exception handling and logging because I'm a bit suspicious that the problem it's somewhere else. So, follow these steps:
Clean up your code for better clarity
Debug the app
Implement some exception handling
Implement some sort of error logging
You should be able to get to the bottom of this issue since there's nothing wrong in sending an array of bytes using the BinaryWrite method

This is real example that pickup from my project
into page.cs set image url dynamically:
// for diffrent url using guid in url
imgProfilePic.ImageUrl = "GenericHandler_ShowImage.ashx?Ref=" + Guid.NewGuid().ToString() + "&n=" + lngEmployeeID;
into handler, get image by table adapter
// in handler
public void ProcessRequest(HttpContext context)
{
long EmployeeID = -1;
if (context.Request.QueryString["n"] != null)
EmployeeID = long.Parse(context.Request.QueryString["n"].ToString());
//else
// throw new ArgumentException("No parameter specified");
if (context.Request.QueryString["actid"] == "2")
{
ShowThumbPic(context, EmployeeID);
return;
}
//else ...
}
private void ShowThumbPic(HttpContext context, long EmployeeID)
{
context.Response.ContentType = "image/jpeg";
Stream myStream = GetEmpImage(EmployeeID);
byte[] myImgByteArray;
using (BinaryReader br = new BinaryReader(myStream))
{
myImgByteArray = br.ReadBytes((int)myStream.Length);
}
MemoryStream ms = new MemoryStream(byteArrayIn);
System.Drawing.Image img = System.Drawing.Image.FromStream(ms);
if (img.Height > 50 || img.Width > 50)
{
System.Drawing.Size siz = GetScaledSize(img.Size, new System.Drawing.Size(50, 50));
img = (System.Drawing.Image)ResizeImage(img, siz);
}
MemoryStream ms = new MemoryStream();
img.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
byte[] myBuffer = ms.ToArray();
int byteSeq = myBuffer.Length; //myStream.Read(myBuffer, 0, 4096);
if (byteSeq > 0)
context.Response.OutputStream.Write(myBuffer, 0, byteSeq);
}
private System.Drawing.Image GetEmployeeImage(long EmployeeID)
{
System.Drawing.Image img = null;
try
{
using (DAL.dstEmployeeTableAdapters.tbl_Employee_InfoTableAdapter ta = new DAL.dstEmployeeTableAdapters.tbl_Employee_InfoTableAdapter())
{
object obj = ta.spr_Employee_Info_GetPicture(EmployeeID);
if (obj != null)
{
MemoryStream ms = new MemoryStream((byte[])obj);
img = System.Drawing.Image.FromStream(ms);
}
}
}
catch (Exception x)
{
throw new Exception(Msg.Error_InDownloadPicture + x.Message);
}
return img;
}
public static Size GetScaledSize(Size ImageSize, Size FrameSize)
{
int newWidth = ImageSize.Width;
int newHeight = ImageSize.Height;
double ratioX = (double)FrameSize.Width / ImageSize.Width;
double ratioY = (double)FrameSize.Height / ImageSize.Height;
double ratio = Math.Min(ratioX, ratioY);
if (ratio < 1.0f) // if Frame is greater than image, resize it.
{
newWidth = (int)(ImageSize.Width * ratio);
newHeight = (int)(ImageSize.Height * ratio);
}
return new Size(newWidth, newHeight);
}
public static System.Drawing.Bitmap ResizeImage(System.Drawing.Image image, Size siz)
{
//a holder for the result
Bitmap result = new Bitmap(siz.Width, siz.Height);
// set the resolutions the same to avoid cropping due to resolution differences
result.SetResolution(image.HorizontalResolution, image.VerticalResolution);
//use a graphics object to draw the resized image into the bitmap
using (Graphics graphics = Graphics.FromImage(result))
{
//set the resize quality modes to high quality
graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//draw the image into the target bitmap
graphics.DrawImage(image, 0, 0, result.Width, result.Height);
}
//return the resulting bitmap
return result;
}

ASP.net c# File being used by another process

I create thumbnails with the following page, Thumbnail.ashx:
<%# WebHandler Language="C#" Class="Thumbnail" %>
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Web;
public class Thumbnail : IHttpHandler {
private int _thumbnailSize = 150;
public void ProcessRequest(HttpContext context) {
string photoName = context.Request.QueryString["p"];
string cachePath = Path.Combine(HttpRuntime.CodegenDir, photoName + ".png");
if (File.Exists(cachePath)) {
OutputCacheResponse(context, File.GetLastWriteTime(cachePath));
context.Response.WriteFile(cachePath);
return;
}
string photoPath = context.Server.MapPath("../uploads/originals/" + photoName);
Bitmap photo;
try {
photo = new Bitmap(photoPath);
}
catch (ArgumentException) {
throw new HttpException(404, "Photo not found.");
}
context.Response.ContentType = "image/png";
int width, height;
if (photo.Width > photo.Height) {
width = _thumbnailSize;
height = photo.Height * _thumbnailSize / photo.Width;
}
else {
width = photo.Width * _thumbnailSize / photo.Height;
height = _thumbnailSize;
}
Bitmap target = new Bitmap(width, height);
using (Graphics graphics = Graphics.FromImage(target)) {
graphics.CompositingQuality = CompositingQuality.HighSpeed;
graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
graphics.CompositingMode = CompositingMode.SourceCopy;
graphics.DrawImage(photo, 0, 0, width, height);
using (MemoryStream memoryStream = new MemoryStream()) {
target.Save(memoryStream, ImageFormat.Png);
OutputCacheResponse(context, File.GetLastWriteTime(photoPath));
using (FileStream diskCacheStream = new FileStream(cachePath, FileMode.CreateNew)) {
memoryStream.WriteTo(diskCacheStream);
}
memoryStream.WriteTo(context.Response.OutputStream);
}
}
}
private static void OutputCacheResponse(HttpContext context, DateTime lastModified) {
HttpCachePolicy cachePolicy = context.Response.Cache;
cachePolicy.SetCacheability(HttpCacheability.Public);
cachePolicy.VaryByParams["p"] = true;
cachePolicy.SetOmitVaryStar(true);
cachePolicy.SetExpires(DateTime.Now + TimeSpan.FromDays(365));
cachePolicy.SetValidUntilExpires(true);
cachePolicy.SetLastModified(lastModified);
}
public bool IsReusable {
get {
return true;
}
}
}
When I try to delete the picture file physically or through code, I get a 'cannot access file, being used by another process" error.
Is this caused by the caching of the thumbnail? Or is the file not being closed somewhere I can't spot?
Could it be my upload file script is causing this?

You don't appear to be closing your MemoryStream anywhere? Garbage collection alone won't remove a file lock, would it? Tossing in a memoryStream.Close() at the end of ProcessRequest couldn't hurt.