使用C#显示图像

Question

我正在使用 mvc2，我想在控制器中使用操作，例如 ShowSmallImage) ，当我输入 www.url.com/ShowSmallImage 时，在浏览器中输出是图像。

我尝试了这样的事情：

public Bitmap CreateThumbnail()
        {
            Image img1 = Image.FromFile(@"C:...\Uploads\Photos\178.jpg");

            int newWidth = 100;
            int newHeight = 100;
            double ratio = 0;

            if (img1.Width > img1.Height)
            {
                ratio = img1.Width / (double)img1.Height;
                newHeight = (int)(newHeight / ratio);
            }
            else
            {
                ratio = img1.Height / (double)img1.Width;
                newWidth = (int)(newWidth / ratio);
            }

            //a holder for the result 
            Bitmap result = new Bitmap(newWidth, newHeight);

            //use a graphics object to draw the resized image into the bitmap 
            using (Graphics graphics = Graphics.FromImage(result))
            {
                //set the resize quality modes to high quality 
                graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
                graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                //draw the image into the target bitmap 
                graphics.DrawImage(img1, 0, 0, result.Width, result.Height);
            }

            return result;
        }

结果我在浏览器中只得到 System.Drawing.Bitmap 。我想我需要设置页面的响应/内容类型，但不知道该怎么做...

谢谢，
岛

Answer 1

创建一个 fileresult 并将流返回到位图&设置内容类型：

    private FileResult RenderImage()
    {   
        MemoryStream stream = new MemoryStream();
        var bitmap = CreateThumbnail();
        bitmap.Save(stream, System.Drawing.Imaging.ImageFormat.Bmp);
        Byte[] bytes = stream.ToArray();
        return File(bytes, "image/png");

    }

Answer 2

在控制器中，例如 ResourceController，您可以有一个返回 FileResult 的 Action。像这样

    public FileResult Thumbnail()
    {
        var bitmap = // Your method call which returns a Bitmap

        var ms = new MemoryStream();
        bitmap.Save(ms, ImageFormat.Png);
        return new FileStreamResult(ms, "image/png");
    }

然后你可以调用http://www.mysite.com/Resource/Thumbnail。