ASP.NET 响应输出流中的 MVC 图像。不工作

Question

我想直接在视图中显示图像，所以我调用了一个操作方法并将图像写入输出流。

但是我收到错误提示 "The image cannot be displayed as it contains error"。我确信图像生成正确但不确定我的控制器代码有什么问题..有没有人遇到过这种情况？

提前致谢..

这是我的控制器操作

[ChildActionOnly]
    public ActionResult GetCaptcha()
    {

        try
        {
            this.Session["CaptchaImageText"] = GenerateRandomCode();

            this.Response.Clear();

            this.Response.ContentType = "image/jpeg";

            Bitmap img = new Bitmap(Server.MapPath("../Images/captcha.jpg"));

            Graphics graphicImage = Graphics.FromImage(img);
            graphicImage.SmoothingMode = SmoothingMode.AntiAlias;

            graphicImage.DrawString(this.Session["CaptchaImageText"].ToString(),
                                    new Font("Arial", 12, FontStyle.Bold),
                                    SystemBrushes.WindowText, new Point(100, 250));

            graphicImage.DrawArc(new Pen(Color.Red, 3), 90, 235, 150, 50, 0, 360);

            //Save the new image to the response output stream.
            img.Save(this.Response.OutputStream, ImageFormat.Jpeg); 

            // Create a CAPTCHA image using the text stored in the Session object.

            graphicImage.Dispose();
            img.Dispose();
        }
        catch (Exception ex)
        {
            ex = null;
        }
        var v = new FileStreamResult(Response.OutputStream,"image/jpeg");
        return v;
    }

下面是我如何从视图中调用操作方法

    <tr><td> <iframe width="200px" height="80px" frameborder="1" scrolling="no"> <img src="@Url.Action("GetCaptcha")" alt="SimpleChart" /> </iframe>  </td></tr>

Answer 1

您需要 return 文件而不是 EmptyResult。

return File(imageByteData, "image/png");

在视图侧：

<tr><td> <iframe>  <img src='@Url.Action("GetCaptcha")'/> </iframe>  </td></tr>

更新

不要写回复而是像下面那样做。

[ChildActionOnly]
public ActionResult GetCaptcha()
{

    try
    {
        byte[] imageByteData = null
        this.Session["CaptchaImageText"] = GenerateRandomCode();

        this.Response.Clear();

        this.Response.ContentType = "image/jpeg";

        Bitmap img = new Bitmap(Server.MapPath("../Images/captcha.jpg"));

        Graphics graphicImage = Graphics.FromImage(img);
        graphicImage.SmoothingMode = SmoothingMode.AntiAlias;

        graphicImage.DrawString(this.Session["CaptchaImageText"].ToString(),
                                new Font("Arial", 12, FontStyle.Bold),
                                SystemBrushes.WindowText, new Point(100, 250));

        graphicImage.DrawArc(new Pen(Color.Red, 3), 90, 235, 150, 50, 0, 360);

        MemoryStream stream = new MemoryStream();
            bitmap.Save(stream, ImageFormat.Jpeg);
            imageByteData = stream.ToArray();

        // Create a CAPTCHA image using the text stored in the Session object.

        graphicImage.Dispose();
        img.Dispose();
        return File(imageByteData, "image/png"); 
    }
    catch (Exception ex)
    {
        ex = null;
    }

}

Answer 2

我认为您使用的 FileStreamResult 有误。

将 img.Save(...) 更改为相同的内存流并在 FileStreamResult(...) return 该内存流中。

ASP.NET 响应输出流中的 MVC 图像。不工作

ASP.NET MVC Image in response output stream. Not working

asp.net-mvc

image

outputstream

response