C＃将图像转换为FileStream

Question

My application so far lets the user select an image via the file selector and upload it through a file stream via FTP:

        Stream ftpStream = request.GetRequestStream();
        FileStream file = File.OpenRead(fileToUpload);
        length = 1024;

        buffer = new byte[length];
           do
            {
                bytesRead = file.Read(buffer, 0, length);
                ftpStream.Write(buffer, 0, bytesRead);
                totalReadBytesCount += bytesRead;
                var progress = totalReadBytesCount * 100.0 / totalToUpload;
                backgroundWorker1.ReportProgress((int)progress);
            }
            while (bytesRead != 0);

This works fine. The selected image is saved as a file and then uploaded.

Now, however, I wish to save it as a 'Image' so I can resize it etc. So that the code would be:

            if (openFileDialog1.ShowDialog() == DialogResult.OK)
        {
            image = Image.FromFile(openFileDialog1.FileName);
        }

As opposed to:

  if (openFileDialog1.ShowDialog() == DialogResult.OK)
    {
        file = openFileDialog1.FileName;
    }

My question thus is:

Now my selected file is a Image file. How do I convert it into the filestream? If this can't be done easily then how would I upload the image via ftp? Thanks in advance.

Answer 1

To write the image to the filestream, I would recommend using the Save function of the Image class. IE

image = Image.FromFile(openFileDialog1.FileName);
image.Save(ftpStream, System.Drawing.Imaging.ImageFormat.Png);

Obviously, you'll need to check for errors and possibly use a different image format.

Answer 2

You may use Image.FromStream Method .

Something like this:

image = Image.FromStream(new MemoryStream(buffer));

To save to FileStream use something like this:

var stream = File.OpenWrite(openFileDialog1.FileName);
image.Save(stream, ImageFormat.Jpeg);