c# - How to convert base64 string to image binary file and save onto server -

this question has answer here:

• c# base64 string jpeg image 4 answers

as example have converted canvas element re-sized image , posted hidden input field that's encoded

data:image/jpeg;base64,/9j/4aaqskzjrgabaqaaaqabaad... 

this value posted same page need convert string image , save onto server.

code behind file (upload.aspx)

protected void btnupload_click(object sender, eventargs e)     {         httppostedfile fileposted = request.files["newinput"];         string base64string = fileposted.tostring();              // convert base64 string byte[]             byte[] imagebytes = convert.frombase64string(base64string);             memorystream ms = new memorystream(imagebytes, 0, imagebytes.length);              // convert byte[] image             ms.write(imagebytes, 0, imagebytes.length);             system.drawing.image image = system.drawing.image.fromstream(ms, true);  //i dont know how write above saveas condition below           if (fileposted != null && fileposted.contentlength > 0)         {             string filenameapplication = path.getfilename(fileposted.filename);             string fileextensionapplication = path.getextension(filenameapplication);              // generating random guid new file @ server uploaded file             string newfile = guid.newguid().tostring() + fileextensionapplication;             // getting valid server path save             string filepath = path.combine(server.mappath("~/assets/") + request.querystring["id"] + "/", newfile);              if (filenameapplication != string.empty)             {                 fileposted.saveas(filepath);             }          } 

i'm pretty sure need convert imagedata binary file before saving on server can't quite how need amend code above. ideas? code save server doesn't work.

once have converted image , changed it's name above - i'm storing database via linq - url appended it.

any appreciated.

hope below functions helps.

public string imagetobase64(image image,           system.drawing.imaging.imageformat format)         {             using (memorystream ms = new memorystream())             {                 // convert image byte[]                 image.save(ms, format);                 byte[] imagebytes = ms.toarray();                  // convert byte[] base64 string                 string base64string = convert.tobase64string(imagebytes);                 return base64string;             }         }          public image base64toimage(string base64string)         {             // convert base64 string byte[]             byte[] imagebytes = convert.frombase64string(base64string);             memorystream ms = new memorystream(imagebytes, 0,               imagebytes.length);              // convert byte[] image             ms.write(imagebytes, 0, imagebytes.length);             image image = image.fromstream(ms, true);             return image;         } 

edit 1 -

from comments seems getting base64 string , need save image on server , whenever required need show image using physical server path.

ok. base64toimage give image base64 string. can save on server using

image.save("path", system.drawing.imaging.imageformat.jpeg); 

and "path" have supplied or created can stored in db url, can use @ time of display.

note: make sure have write access folder saving image.

edit-2 function should below. please put validation code, error handling required.

protected void btnupload_click(object sender, eventargs e)     {         httppostedfile fileposted = request.files["newinput"];         string base64string = fileposted.tostring();              // convert base64 string byte[]             byte[] imagebytes = convert.frombase64string(base64string);             memorystream ms = new memorystream(imagebytes, 0, imagebytes.length);              // convert byte[] image             ms.write(imagebytes, 0, imagebytes.length);             system.drawing.image image   = system.drawing.image.fromstream(ms, true);             string newfile = guid.newguid().tostring() + fileextensionapplication;             string filepath = path.combine(server.mappath("~/assets/") + request.querystring["id"] + "/", newfile);             image.save(filepath,imageformat.jpeg);    }