Image 如何使一个单一的图像在不同的（优化）大小，一旦图像上传？

这是我拍的 这是我发送给你的，请看一下，检查一下，这是做这项工作的正确方法

 UploadController  class file


 public class UploadController : ApiController
    {


    public async Task<HttpResponseMessage> Post()
    {
        if (!Request.Content.IsMimeMultipartContent("form-data"))
        {
            throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
        }

        var uploadFolder = HostingEnvironment.MapPath("~/app_data");
        uploadFolder = Path.Combine(uploadFolder, DateTime.Now.ToString("yyyyMMddhhmmssfff"));
        Directory.CreateDirectory(uploadFolder);
        var streamProvider = new PreserveFilenameMultipartFileStreamProvider(uploadFolder);

        var parts = await Request.Content.ReadAsMultipartAsync(streamProvider);
        foreach (var uploadedFile in Directory.GetFiles(uploadFolder))
        {
            var thumbnail = Path.Combine(uploadFolder, "thumb-" + Path.GetFileName(uploadedFile));
            var medium = Path.Combine(uploadFolder, "medium-" + Path.GetFileName(uploadedFile));
            var large = Path.Combine(uploadFolder, "large-" + Path.GetFileName(uploadedFile));
            ImageTools.Resize(uploadedFile, thumbnail, 100, 100);
            ImageTools.Resize(uploadedFile, medium, 200, 200);
            ImageTools.Resize(uploadedFile, large, 300, 300);
        }

        return Request.CreateResponse(HttpStatusCode.Accepted);

我又拿了一个文件，名字是

  PreserveFilenameMultipartFileStreamProvider




    public class PreserveFilenameMultipartFileStreamProvider : MultipartFileStreamProvider
    {
        public PreserveFilenameMultipartFileStreamProvider(string rootPath)
            : base(rootPath)
        {
        }

        public override string GetLocalFileName(HttpContentHeaders headers)
        {
            return headers.ContentDisposition.FileName.Replace("\"", "");
        }
    }

最后是我的布局页面

     @using (Html.BeginRouteForm("DefaultApi", new { httproute = "", controller = "images" }, FormMethod.Post, new { enctype = "multipart/form-data" }))
{
    <input type="file" name="image" multiple="multiple" accept="image/*" />
    <button type="submit">Upload</button>
}

@使用（Html.beginroutform（“DefaultApi”，new{httproute=“”，controller=“images”}，FormMethod.Post，new{enctype=“multipart/form data”}））
{
上传
}

您可以使用。或者你也可以

---

更新：下面是一个示例，您可以使用它在Web API控制器中调整上载图像的大小

您可以从编写一个Resize方法开始，该方法将使用GDI+，如我链接到的前一篇文章所示：

public static class ImageTools
{
    public static void Resize(string original, string output, int width, int height)
    {
        using (var image = Image.FromFile(original))
        using (var thumbnail = new Bitmap(width, height))
        using (var graphics = Graphics.FromImage(thumbnail))
        {
            graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
            graphics.SmoothingMode = SmoothingMode.HighQuality;
            graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
            graphics.CompositingQuality = CompositingQuality.HighQuality;

            graphics.DrawImage(image, 0, 0, width, height);

            ImageCodecInfo[] info = ImageCodecInfo.GetImageEncoders();
            EncoderParameters encoderParameters;
            encoderParameters = new EncoderParameters(1);
            encoderParameters.Param[0] = new EncoderParameter(Encoder.Quality, 100L);
            thumbnail.Save(output, info[1], encoderParameters);
        }
    }
}

然后是一个自定义的

MultipartFileStreamProvider

，它将保留最初上载的文件名：

public class PreserveFilenameMultipartFileStreamProvider : MultipartFileStreamProvider
{
    public PreserveFilenameMultipartFileStreamProvider(string rootPath): base(rootPath)
    {
    }

    public override string GetLocalFileName(HttpContentHeaders headers)
    {
        return headers.ContentDisposition.FileName.Replace("\"", "");
    }
}

最后，您可以使用API控制器接收上传的图像，将它们存储在

App_Data

文件夹中，并通过调整大小生成不同的格式：

public class ImagesController : ApiController
{
    public async Task<HttpResponseMessage> Post()
    {
        if (!Request.Content.IsMimeMultipartContent("form-data"))
        {
            throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
        }

        var uploadFolder = HostingEnvironment.MapPath("~/app_data");
        uploadFolder = Path.Combine(uploadFolder, DateTime.Now.ToString("yyyyMMddhhmmssfff"));
        Directory.CreateDirectory(uploadFolder);
        var streamProvider = new PreserveFilenameMultipartFileStreamProvider(uploadFolder);

        await Request.Content.ReadAsMultipartAsync(streamProvider);
        foreach (var uploadedFile in Directory.GetFiles(uploadFolder))
        {
            var thumbnail = Path.Combine(uploadFolder, "thumb-" + Path.GetFileName(uploadedFile));
            var medium = Path.Combine(uploadFolder, "medium-" + Path.GetFileName(uploadedFile));
            var large = Path.Combine(uploadFolder, "large-" + Path.GetFileName(uploadedFile));
            ImageTools.Resize(uploadedFile, thumbnail, 100, 100);
            ImageTools.Resize(uploadedFile, medium, 200, 200);
            ImageTools.Resize(uploadedFile, large, 300, 300);
        }

        return Request.CreateResponse(HttpStatusCode.Accepted);
    }
}

---

是的，这是更好的，但我需要这样做手动像写硬代码我怎么能做到这一点有任何想法请帮助你阅读了我的答案中链接到的文章（第二篇关于使用GDI+手动调整图像大小的文章）？你试过什么？您遇到了什么困难？是的，它在mvc3（webapi）中正常工作，但我需要在mvc4中手动完成此工作。谢谢您的回复，如果有任何帮助，请帮助我。您尝试了什么？你能出示你的密码吗？你遇到了什么问题？我已经更新了我的答案，以说明一个可以让您开始学习的示例。好的，我将更新.NET 4.0的答案。下次你提问时，请务必提供这些细节，因为它们非常重要。现在请参见结尾处的我的

更新2

。

public class ImagesController : ApiController
{
    public async Task<HttpResponseMessage> Post()
    {
        if (!Request.Content.IsMimeMultipartContent("form-data"))
        {
            throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
        }

        var uploadFolder = HostingEnvironment.MapPath("~/app_data");
        uploadFolder = Path.Combine(uploadFolder, DateTime.Now.ToString("yyyyMMddhhmmssfff"));
        Directory.CreateDirectory(uploadFolder);
        var streamProvider = new PreserveFilenameMultipartFileStreamProvider(uploadFolder);

        await Request.Content.ReadAsMultipartAsync(streamProvider);
        foreach (var uploadedFile in Directory.GetFiles(uploadFolder))
        {
            var thumbnail = Path.Combine(uploadFolder, "thumb-" + Path.GetFileName(uploadedFile));
            var medium = Path.Combine(uploadFolder, "medium-" + Path.GetFileName(uploadedFile));
            var large = Path.Combine(uploadFolder, "large-" + Path.GetFileName(uploadedFile));
            ImageTools.Resize(uploadedFile, thumbnail, 100, 100);
            ImageTools.Resize(uploadedFile, medium, 200, 200);
            ImageTools.Resize(uploadedFile, large, 300, 300);
        }

        return Request.CreateResponse(HttpStatusCode.Accepted);
    }
}

@{
    Layout = null;
}
<!DOCTYPE html>
<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
</head>
<body>
    @using (Html.BeginRouteForm("DefaultApi", new { httproute = "", controller = "images" }, FormMethod.Post, new { enctype = "multipart/form-data" }))
    {
        <input type="file" name="image" multiple="multiple" accept="image/*" />
        <button type="submit">Upload</button>
    }
</body>  
</html>

public class ImagesController : ApiController
{
    public Task<HttpResponseMessage> Post()
    {
        if (!Request.Content.IsMimeMultipartContent("form-data"))
        {
            throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
        }

        var uploadFolder = HostingEnvironment.MapPath("~/app_data");
        uploadFolder = Path.Combine(uploadFolder, DateTime.Now.ToString("yyyyMMddhhmmssfff"));
        Directory.CreateDirectory(uploadFolder);
        var streamProvider = new PreserveFilenameMultipartFileStreamProvider(uploadFolder);

        return Request.Content.ReadAsMultipartAsync(streamProvider).ContinueWith(t =>
        {
            foreach (var uploadedFile in Directory.GetFiles(uploadFolder))
            {
                var thumbnail = Path.Combine(uploadFolder, "thumb-" + Path.GetFileName(uploadedFile));
                var medium = Path.Combine(uploadFolder, "medium-" + Path.GetFileName(uploadedFile));
                var large = Path.Combine(uploadFolder, "large-" + Path.GetFileName(uploadedFile));
                ImageTools.Resize(uploadedFile, thumbnail, 100, 100);
                ImageTools.Resize(uploadedFile, medium, 200, 200);
                ImageTools.Resize(uploadedFile, large, 300, 300);
            }
            return Request.CreateResponse(HttpStatusCode.Accepted);
        });
    }
}