FileHeaderEncode验证后保存文件时出现问题 [英] Problem in Saving the File after FileHeaderEncode Verification

问题描述

我在FileHeaderEncode验证后保存文件时遇到问题.

我只是想验证上传的文档实际上是jpeg图像，而不仅仅是说一个重命名为.jpeg扩展名的文本文件.

为了验证这一点，我使用了一种称为"DetectFileheaderEncode"的方法.但是，每当我使用此方法并尝试保存图像时，它会将图像保存为0大小，因此，该图像不可用?

请你帮助我好吗?

谢谢

乖dd

代码如下:

Hi, I''m having a problem saving a file after FileHeaderEncode verification.

I am just trying to verify that the uploaded document is actually a jpeg image, not just say, a Text file renamed to have a .jpeg extension.

To verify this I use method which I called "DetectFileheaderEncode". But whenever I use this method and try to save the image, it saves the image as 0 size therefore, the image is not available?

Could you please help me?

Thank you,

codddy

The code is as below:

 protected void btnUpload_Click(object sender, EventArgs e)
        {
            String savePath = @"C:\\Users\\xx\\Desktop\\fileupload\\";

            try
            {
                if (FileUpload1.HasFile)
                {
                    string fileName = Server.HtmlEncode(FileUpload1.FileName);

                    Boolean verified = VerifyUploadJpegImage(FileUpload1);

                    if (verified) 
                    {

                        // Append the name of the file to upload to the path.
                        savePath += fileName;

                        FileUpload1.SaveAs(savePath);

                        // Notify the user that their file was successfully uploaded.
                        lblUploadStatus.Text = "Your file was uploaded successfully.";
                        lblUploadStatus.ForeColor = Color.Green;
                    }
                    else
                    {
                        // Invalid upload file
                        // notify the user why their file was not uploaded.
                        lblUploadStatus.Text = "Your file was not uploaded because " +
                                                 "it is not a jpegImage";
                        lblUploadStatus.ForeColor = Color.Red;
                    }

                }
                else
                {
                    lblUploadStatus.Text = "You have not specified a file.";
                }
            }
            catch (Exception ex)
            {
                lblUploadStatus.Text = "ERROR:" + ex.Message;
            }

        }


private Boolean VerifyUploadJpegImage(FileUpload fileUpload)
        {
            Boolean verified = false;

            String fileName = Server.HtmlEncode(fileUpload.FileName);

            String extension = System.IO.Path.GetExtension(fileName);

            String contentType = fileUpload.PostedFile.ContentType;


            String fileheaderEncoding = DetectFileheaderEncode(fileUpload);

            if (((extension == ".jpg") || (extension == ".jpeg")) && (contentType == "image/jpeg") && (fileheaderEncoding == "255216"))
            {
                verified = true;
            }

            return verified;
        }

        private String DetectFileheaderEncode(FileUpload fileUpload)
        {
            String encode = String.Empty;
           
            System.IO.BinaryReader r = new System.IO.BinaryReader(fileUpload.PostedFile.InputStream);
            string fileclass = "";
            byte buffer;
            try
            {
                buffer = r.ReadByte();
                fileclass = buffer.ToString();
                buffer = r.ReadByte();
                fileclass += buffer.ToString();
            }
            catch(Exception ex)
            {

            }

            r.Close();

            encode = fileclass;

            return encode;
        }

推荐答案

好，我解决了这个问题. :)

我刚刚在DetectFileheaderEncode方法中注释了r.Close()，它现在可以正常工作.

Ok I solved the problem. :)

I just commented out r.Close() in DetectFileheaderEncode method, and it''s working correctly now.

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