使用Linq to SQL从数据库中检索图像

Question

In my database I have stored images in the "image" data type, showing up as a binary code. I now want to retrieve all images from one column and diplay them on a asp.net page with C#.

databaseDataContext db = new databaseDataContext();

    var images = from Picture p in db.Pictures
                 select p.pictureThumb;

then I use this:

    foreach (Picture p in images)
    {
        galleryImages.Controls.Add(p);
    }

But that doesn't work because Binary can't be converted to Picture. I have Googled this and found that I have to cast to Byte and then to image? I can't find examples on how to do that though.

Answer 1

This should do it:

databaseDataContext db = new databaseDataContext();

var images = from p in db.Pictures
             select Image.FromStream(new MemoryStream(p.pictureThumb.ToArray());
foreach (Image image in images)
{
    galleryImages.Controls.Add(image);
}

Note that Image.FromStream takes ownership of the stream - it's only a MemoryStream anyway, but do make sure that you dispose of the image, for various reasons.

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EDIT: Ah... I hadn't realised that this was for ASP.NET. That makes things harder - because the HTML is going to contain URLs, and then you'll need to be able to fetch the data later.

Does a picture have an ID of some kind? If so, fetch that instead of the actual data, and then set up a URL which is able to serve any thumbnail based on the ID (by fetching it from the database and just serving it with an appropriate content type).