How to output an excel spreadsheet with images from ASP.net

Suppose I'm writing an ASP.net web application.

The original designer of the application was using "PopChart" to make some images appear in the web application. One of the pages had an "Export To Excel" button on it. When the button is clicked, the page content is output to Excel as in this tutorial: http://aspalliance.com/articleViewer.aspx?aId=1&pId=.

Basically, it's outputting HTML to an XLS file and Excel interprets it. The problem is, I need to get rid of PopChart. I've replaced it with a web control that outputs a PNG file (which incidently, can be saved in a MemoryStream object at runtime). PopChart references a flash component that runs from a public server; the data on the "PopChart" is embedded in the HTML.

However, once I start using the web control that outputs PNG, all the data is in a single PNG file. I cannot see that there is any way to output the PNG file with the HTML. I tried embedding the data into the img src=..., but Excel won't interpret it. Neither can Excel download the PNG file from the server; the server is locked down and Excel doesn't have access to the browser session.

What can I do?

Update: I found the following code sample given on the MSDN forums:

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

using DocumentFormat.OpenXml;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Spreadsheet;
using DocumentFormat.OpenXml.Validation;
using DocumentFormat.OpenXml.Drawing.Spreadsheet;

using System.IO;
using System.Drawing;

namespace ConsoleApplication4
{
    class Program
    {
        static void Main(string[] args)
        {
            string sFile = "ExcelOpenXmlWithImage.xlsx";
            if (File.Exists(sFile))
            {
                File.Delete(sFile);
            }
            BuildWorkbook(sFile);
        }

        private static void BuildWorkbook(string filename)
        {
            try
            {
                using (SpreadsheetDocument xl = SpreadsheetDocument.Create(filename, SpreadsheetDocumentType.Workbook))
                {
                    WorkbookPart wbp = xl.AddWorkbookPart();
                    WorksheetPart wsp = wbp.AddNewPart<WorksheetPart>();                                 
                    Workbook wb = new Workbook();
                    FileVersion fv = new FileVersion();
                    fv.ApplicationName = "Microsoft Office Excel";
                    Worksheet ws = new Worksheet();
                    SheetData sd = new SheetData();

                    //string sImagePath = "polymathlogo.png";
                    string sImagePath = @"c:\temp\chartImg.png";
                    DrawingsPart dp = wsp.AddNewPart<DrawingsPart>();
                    ImagePart imgp = dp.AddImagePart(ImagePartType.Png, wsp.GetIdOfPart(dp));
                    using (FileStream fs = new FileStream(sImagePath, FileMode.Open))
                    {
                  开发者_高级运维      imgp.FeedData(fs);
                    }

                    NonVisualDrawingProperties nvdp = new NonVisualDrawingProperties();
                    nvdp.Id = 1025;
                    nvdp.Name = "Picture 1";
                    nvdp.Description = "polymathlogo";
                    DocumentFormat.OpenXml.Drawing.PictureLocks picLocks = new DocumentFormat.OpenXml.Drawing.PictureLocks();
                    picLocks.NoChangeAspect = true;
                    picLocks.NoChangeArrowheads = true;
                    NonVisualPictureDrawingProperties nvpdp = new NonVisualPictureDrawingProperties();
                    nvpdp.PictureLocks = picLocks;
                    NonVisualPictureProperties nvpp = new NonVisualPictureProperties();
                    nvpp.NonVisualDrawingProperties = nvdp;
                    nvpp.NonVisualPictureDrawingProperties = nvpdp;

                    DocumentFormat.OpenXml.Drawing.Stretch stretch = new DocumentFormat.OpenXml.Drawing.Stretch();
                    stretch.FillRectangle = new DocumentFormat.OpenXml.Drawing.FillRectangle();                    

                    BlipFill blipFill = new BlipFill();
                    DocumentFormat.OpenXml.Drawing.Blip blip = new DocumentFormat.OpenXml.Drawing.Blip();
                    blip.Embed = dp.GetIdOfPart(imgp);
                    blip.CompressionState = DocumentFormat.OpenXml.Drawing.BlipCompressionValues.Print;
                    blipFill.Blip = blip;
                    blipFill.SourceRectangle = new DocumentFormat.OpenXml.Drawing.SourceRectangle();
                    blipFill.Append(stretch);

                    DocumentFormat.OpenXml.Drawing.Transform2D t2d = new DocumentFormat.OpenXml.Drawing.Transform2D();
                    DocumentFormat.OpenXml.Drawing.Offset offset = new DocumentFormat.OpenXml.Drawing.Offset();
                    offset.X = 1000;
                    offset.Y = 1000;
                    t2d.Offset = offset;
                    Bitmap bm = new Bitmap(sImagePath);
                    //http://en.wikipedia.org/wiki/English_Metric_Unit#DrawingML
                    //http://stackoverflow.com/questions/1341930/pixel-to-centimeter
                    //http://stackoverflow.com/questions/139655/how-to-convert-pixels-to-points-px-to-pt-in-net-c
                    DocumentFormat.OpenXml.Drawing.Extents extents = new DocumentFormat.OpenXml.Drawing.Extents();
                    extents.Cx = (long)bm.Width * (long)((float)914400 / bm.HorizontalResolution);
                    extents.Cy = (long)bm.Height * (long)((float)914400 / bm.VerticalResolution);
                    bm.Dispose();
                    t2d.Extents = extents;
                    ShapeProperties sp = new ShapeProperties();
                    sp.BlackWhiteMode = DocumentFormat.OpenXml.Drawing.BlackWhiteModeValues.Auto;
                    sp.Transform2D = t2d;
                    DocumentFormat.OpenXml.Drawing.PresetGeometry prstGeom = new DocumentFormat.OpenXml.Drawing.PresetGeometry();
                    prstGeom.Preset = DocumentFormat.OpenXml.Drawing.ShapeTypeValues.Rectangle;
                    prstGeom.AdjustValueList = new DocumentFormat.OpenXml.Drawing.AdjustValueList();
                    sp.Append(prstGeom);
                    sp.Append(new DocumentFormat.OpenXml.Drawing.NoFill());

                    DocumentFormat.OpenXml.Drawing.Spreadsheet.Picture picture = new DocumentFormat.OpenXml.Drawing.Spreadsheet.Picture();
                    picture.NonVisualPictureProperties = nvpp;
                    picture.BlipFill = blipFill;
                    picture.ShapeProperties = sp;

                    Position pos = new Position();
                    pos.X =(Int64) 1000;
                    pos.Y =(Int64) 1000;
                    Extent ext = new Extent();
                    ext.Cx = extents.Cx;
                    ext.Cy = extents.Cy;
                    AbsoluteAnchor anchor = new AbsoluteAnchor();
                    anchor.Position = pos;
                    anchor.Extent = ext;
                    anchor.Append(picture);
                    anchor.Append(new ClientData());
                    WorksheetDrawing wsd = new WorksheetDrawing();
                    wsd.Append(anchor);
                    Drawing drawing = new Drawing();
                    drawing.Id = dp.GetIdOfPart(imgp);

                    wsd.Save(dp);                    

                    ws.Append(sd);
                    ws.Append(drawing);
                    wsp.Worksheet = ws;
                    wsp.Worksheet.Save();
                    Sheets sheets = new Sheets();
                    Sheet sheet = new Sheet();
                    sheet.Name = "Sheet1";
                    sheet.SheetId = 1;
                    sheet.Id = wbp.GetIdOfPart(wsp);
                    sheets.Append(sheet);
                    wb.Append(fv);
                    wb.Append(sheets);

                    xl.WorkbookPart.Workbook = wb;
                    xl.WorkbookPart.Workbook.Save();
                    xl.Close();
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
                Console.ReadLine();
            }
        }


    }
}

This code functions to create a new Excel spreadsheet with an image embedded in it. However, I have been unable to modify this code to place the image where I want to on the spreadsheet. (Yes, I did try changing the value of the offset.) I also have not successfully added any text or numeric data to the rows and columns.

Has anyone here gotten this to work?

---

Take a look at the NPOI library, which is a great library for generating Excel (and other Office type) documents in .Net.

With their library, they have a sample demonstrating how to load images into Excel, which reads from a file. Since you can have your POPChart can save the images as a memory stream, you can easily take their example and modify it to read from the memory stream instead of the file. The rest of the Excel generation process should be easy enough.

---

To change the location of your picture you need to change the rowId and columnId. They act as row and column indices, so if you have ColumnId cId = new ColumnId("2"); and RowId rId = new RowId("1"); your image will be placed at cell C2. You will need to do this twice, once for the starting indices and once for the ending indices if you are using a twoCellAnchor.