binaray阅读器问题，二进制阅读器不读取字节。 [英] binaray reader problem ,binary reader not reading bytes.

问题描述

此代码运行良好

会话[  fileUpl] = fileUpl; lblFileUpload.Text = fileUpl.FileName; 
会话[ 图像] = fileUpl.PostedFile; 
 Stream fs = fileUpl.PostedFile.InputStream; 
 BinaryReader br =  new  BinaryReader（fs）; 
  byte  [] bytes = br.ReadBytes（（ Int32 ）fs.Length）; 
  string  base64String = Convert.ToBase64String（bytes， 0 ，bytes.Length）; 
 Image1.ImageUrl =   data：image / png; base64， + base64String; 

但是下面这段代码不起作用，fs.length显示文件长度但是bites数组显示0字节。这意味着二进制阅读器不开心有什么。我不知道为什么请帮忙。

 fileUpl =（FileUpload）Session [  fileUpl]; lblFileUpload.Text = fileUpl.FileName; 
 HttpPostedFile postedFile =（HttpPostedFile）Session [  Image]; 
 Stream fs = postingFile.InputStream; 
 BinaryReader br =  new  BinaryReader（fs）; 
  byte  [] bytes = br.ReadBytes（（ Int32 ）fs.Length）; 
  string  base64String = Convert.ToBase64String（bytes， 0 ，bytes.Length）; 
 Image1.ImageUrl =   data：image / png; base64， + base64String; 
 

解决方案

将PostedFile的byte []放入会话并在下次访问时

 Stream fs = fileUpl.PostedFile.InputStream; 
 BinaryReader br =  new  BinaryReader（fs）; 
会话[  bytes] = br.ReadBytes（（ Int32 ）fs.Length）; 

然后

  byte  [] bytes =（ byte  []）会话[  bytes] 
  string  base64String = Convert.ToBase64String（bytes， 0 ，bytes.Length）; 
 Image1.ImageUrl =   data：image / png; base64， + base64String; 

This code works perfectly well

Session["fileUpl"] = fileUpl; lblFileUpload.Text = fileUpl.FileName;
            Session["Image"] = fileUpl.PostedFile;
            Stream fs = fileUpl.PostedFile.InputStream;
            BinaryReader br = new BinaryReader(fs);
            byte[] bytes = br.ReadBytes((Int32)fs.Length);
            string base64String = Convert.ToBase64String(bytes, 0, bytes.Length);
            Image1.ImageUrl = "data:image/png;base64," + base64String;

but this code below does not works ,fs.length shows file lenght but bites array shows 0 bytes .that means binary reader is not happy with something .i dont know why please help.

fileUpl = (FileUpload)Session["fileUpl"]; lblFileUpload.Text = fileUpl.FileName;
           HttpPostedFile postedFile = (HttpPostedFile)Session["Image"];
           Stream fs = postedFile.InputStream;
           BinaryReader br = new BinaryReader(fs);
           byte[] bytes = br.ReadBytes((Int32)fs.Length);
           string base64String = Convert.ToBase64String(bytes, 0, bytes.Length);
           Image1.ImageUrl = "data:image/png;base64," + base64String;

解决方案

put byte[] of PostedFile to the session and access it next time

Stream fs = fileUpl.PostedFile.InputStream;
BinaryReader br = new BinaryReader(fs);
Session["bytes"] = br.ReadBytes((Int32)fs.Length);

then

byte[] bytes = (byte[])Session["bytes"]
string base64String = Convert.ToBase64String(bytes, 0, bytes.Length);
Image1.ImageUrl = "data:image/png;base64," + base64String;

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