检查上传图片的尺寸

Question

我在我的网站上使用 asp.net 3.5 和 c#。这是我的问题：

我的页面上有一个上传按钮和 asp:Image。用户可以从他的计算机上传图像，该图像将显示在 asp:image 中。但在显示图像之前，我想检查上传图像的宽度和高度。我该怎么做？

Answer 1

    Image img = System.Drawing.Image.FromFile("test.jpg");
    int width = img.Width;
    int height = img.Height;

您可能需要添加 System.Drawing 引用。

如果您尚未将图像保存到磁盘，您也可以使用 FromStream 函数，但看看您如何使用图像（用户可以在图像控件中查看），我怀疑它已经打开磁盘。流到图像可能比磁盘到图像快，也可能不快。您可能需要进行一些分析以查看哪个具有更好的性能。

Answer 2

在 ASP.NET 中，上传文件时通常会使用 byte[] 或 Stream。下面，我向您展示一种方法，其中 bytes 是上传文件的 byte[]。如果您首先保存文件，那么您就有了一个物理文件。您可以使用@Jakob 或@Fun Mun Pieng 向您展示的内容。

无论哪种方式，请务必像我在此处所示的那样处理您的 Image 实例。这非常重要（其他人没有展示这一点）。

  using (Stream memStream = new MemoryStream(bytes))
  {
    using (Image img = System.Drawing.Image.FromStream(memStream))
    {
      int width = img.Width;
      int height = img.Height;
    }
  }

Answer 3

请尝试以下操作：

public bool ValidateFileDimensions()
{
    using(System.Drawing.Image myImage =
           System.Drawing.Image.FromStream(FileUpload1.PostedFile.InputStream))
    {
        return (myImage.Height == 140 && myImage.Width == 140);
    }
}

Answer 4

将图像加载到 图像 并检查服务器端的尺寸？

Image uploadedImage = Image.FromFile("uploadedimage.jpg");
// uploadedImage.Width and uploadedImage.Height will have the dimensions...

Answer 5

试试这个：

Stream ipStream = fuAttachment.PostedFile.InputStream;
using (var image = System.Drawing.Image.FromStream(ipStream))
{                    
    float w = image.PhysicalDimension.Width;
    float h = image.PhysicalDimension.Height;
}

Answer 6

试试这个。

              public boolean CheckImgDimensions(string imgPath, int ValidWidth , int ValidHeight){  

                 var img = Image.FromFile(Server.MapPath(imgPath));

                 return (img.width == ValidWidth &&  img.height == ValidHeight );
                }

使用：

if ( CheckImgDimensions("~/Content/img/MyPic.jpg",128,128) ){ 
     /// what u want
  }

Answer 7

这就是我检查控制器 ActionResult 的方法：

public ActionResult ThumbnailUpload(HttpPostedFileBase image, PressRelease pr)
{
    var id = pr.Id;
    if (id == null)
    {
        return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
    }
    PressRelease pressRelease = db.PressReleases.Find(id);
    if (pressRelease == null)
    {
        return HttpNotFound();
    }
    bool success = false;
    var imgName = "";
    var path = "";
    ViewBag.Message = "";
    try
    {
        //Check for uploaded file
        //You can set max file upload size in your Web.config file
        if (image.ContentLength > 0)
        {                   
            //Check the uploaded file is of the type needed/required
            if (Path.GetExtension(image.FileName) == ".jpg")
            {
                //Get the uploaded file from HttpPostedFileBase
                System.IO.Stream stream = image.InputStream;

                //Convert the uploaded file to Image
                System.Drawing.Image img = System.Drawing.Image.FromStream(stream);

                //Get the Width and Height of the uploaded file
                int width = img.Width;
                int height = img.Height;

                //Check the Width & Height are the dimensions you want
                if (width != 150 && height != 175)
                {
                    //If the Width & Height do not meet your specifications, write a message to the user
                    success = false;
                    ViewBag.Message = "Thumbnail upload failed.";
                    ViewBag.Exception = "Image dimensions must 150w by 175h.";

                    //Return the view with the Model so error messages get displayed
                    return View("UploadImages", pressRelease);
                }
                else
                {
                    //If Width & Height meet your specs, continue with uploading and saving the image
                    imgName = Path.GetFileName(image.FileName);
                    path = Path.Combine(Server.MapPath("...Your File Path..."), imgName);
                    image.SaveAs(path);
                    success = true;
                    ViewBag.Success = success;
                    ViewBag.Message = "Thumbnail uploaded successfully.";
                    pressRelease.ThumbName = Path.GetFileNameWithoutExtension(image.FileName);
                    TryUpdateModel(pressRelease);
                    db.SaveChanges();
                }
            }
            else if(Path.GetExtension(image.FileName) != ".jpg")
            {
                //If the uploaded file is not of the type needed write message to user
                success = false;
                ViewBag.Message = "Thumbnail upload failed.";
                ViewBag.Exception = "Uploaded file must have '.jpg' as the file extension.";
                return View("UploadImages", pressRelease);
            }
        }
        return View("UploadImages", pressRelease);
    }
    catch (Exception ex)
    {
        ViewBag.Success = success;
        ViewBag.Exception = ex.Message;
        ViewBag.Message = "Thumbnail upload failed.";
        return View("UploadImages", pressRelease);
    }
}

我希望这可以帮助遇到这个问题的其他人。