Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
137 views
in Technique[技术] by (71.8m points)

c# - Save and retrieve image (binary) from SQL Server using Entity Framework 6

I am trying to save a bitmap image to database

Bitmap map = new Bitmap(pictureBoxMetroMap.Size.Width, pictureBoxMetroMap.Size.Height);

I created a column imgcontent in the database with datatype binary but my problem is how can I convert this bitmap (map) to binary data?

And how can I retrieve data from database?

I googled it and I found something like this but it didn't work:

byte[] arr;
ImageConverter converter = new ImageConverter();
arr = (byte[])converter.ConvertTo(map, typeof(byte[]));
Question&Answers:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

Convert the image to a byte[] and store that in the database.


Add this column to your model:

public byte[] Content { get; set; }

Then convert your image to a byte array and store that like you would any other data:

public byte[] ImageToByteArray(System.Drawing.Image imageIn)
{
    using(var ms = new MemoryStream())
    {
        imageIn.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
    
        return ms.ToArray();
    }
}

public Image ByteArrayToImage(byte[] byteArrayIn)
{
     using(var ms = new MemoryStream(byteArrayIn))
     {
         var returnImage = Image.FromStream(ms);

         return returnImage;
     }
}

Source: Fastest way to convert Image to Byte array

var image = new ImageEntity()
{
   Content = ImageToByteArray(image)
};

_context.Images.Add(image);
_context.SaveChanges();

When you want to get the image back, get the byte array from the database and use the ByteArrayToImage and do what you wish with the Image

This stops working when the byte[] gets to big. It will work for files under 100Mb


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...