Picture Library Image size event receiver

Question

I created a event receiver but work ok for single file but no work for multiple files,

HttpFileCollection collection = _context.Request.Files;
            for (int i = 0; i < collection.Count; i++)
            {
                HttpPostedFile postedFile = collection[i];

                Stream fileStream = postedFile.InputStream;
                fileStream.Position = 0;
                byte[] fileContents = new byte[postedFile.ContentLength];
                fileStream.Read(fileContents, 0, postedFile.ContentLength);

                System.Drawing.Image image = System.Drawing.Image.FromStream(new System.IO.MemoryStream(fileContents));

                int imageHeight = image.Height;
                int imageWidth = image.Width;

when multiple file upload it asks,

object reference no set...

at first line, what to do sir

Answer 1

Picture Library Schema contains fields ImageWidth and ImageHeight. You could get it in your receiver. For example:

public override void ItemAdded(SPItemEventProperties properties)
{
    if (properties.ListItem["ImageWidth"].ToString() == "300")
    {
       //your code here
    } 
}

Fields ImageWidth and ImageHeight are filled only in ItemAdded/ItemUpdated events.

---

If you want to get image sizes in ItemAdding you could get file from HttpContext and wrap it into System.Drawing.Image.

Here is sample event receiver:

public class PicsReceiver : SPItemEventReceiver
{

    private HttpContext _context;

    public PicsReceiver()
    {
        _context = HttpContext.Current;
    }

    public override void ItemAdding(SPItemEventProperties properties)
    {
        base.ItemAdding(properties);

        string searchForFileName = Path.GetFileName(properties.BeforeUrl);
        HttpFileCollection collection = _context.Request.Files;
        for (int i = 0; i < collection.Count; i++)
        {
            HttpPostedFile postedFile = collection[i];
            if (searchForFileName.Equals(
                Path.GetFileName(postedFile.FileName), StringComparison.OrdinalIgnoreCase))
            {
                Stream fileStream = postedFile.InputStream;
                Image img = Image.FromStream(fileStream);
                //use img.Width and img.Height to get file sizes
            }
        }
    }
}

I found that method in William van Strien's blog.

NOTE: You need to add references to System.Web.dll and System.Drawing.dll.

Answer 2

I created the same thing a few years back. Here's the code if it helps u

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.SharePoint;
using System.IO;
using Microsoft.SharePoint.Utilities;
using System.Drawing;
namespace SharepointImageResizerProject
{
    class ImageResizerEventHandler : SPItemEventReceiver
    {
        public override void ItemAdded(SPItemEventProperties properties)
        {
            try
            {
                //Check user is site admin , remove it if you dont need it
                if (properties.OpenWeb().CurrentUser.IsSiteAdmin)
                {
                    SPFile file = properties.ListItem.File;
                    if (null != file)
                    {
                        properties.OpenWeb().AllowUnsafeUpdates = true;
                        try
                        {
                            MemoryStream msOut = new MemoryStream();
                            MemoryStream msIn = new MemoryStream(file.OpenBinary(), true);
                            int width = 100; //set to desired value 
                            int height = 200; //set to desired value 
                            Image img = Image.FromStream(msIn).GetThumbnailImage(width, height, null, IntPtr.Zero);
                            img.Save(msOut, System.Drawing.Imaging.ImageFormat.Jpeg);
                            file.SaveBinary(msOut, false);
                            file.CheckOut();
                            file.Update();
                            file.CheckIn(string.Empty);
                        }
                        finally
                        {
                            properties.OpenWeb().AllowUnsafeUpdates = false;
                        }
                    }
                }
            }
            catch
            {
                //Do some exception handling 
                throw;
            }
        }
        public override void ItemAdding(SPItemEventProperties properties)
        {
            base.ItemAdding(properties);
        }
        public override void ItemUpdated(SPItemEventProperties properties)
        {
            base.ItemUpdated(properties);
        }
        public override void ItemUpdating(SPItemEventProperties properties)
        {
            base.ItemUpdating(properties);
        }
    }
}