How to pass content of image file from fileupload control to web method via javascript?

Question

Hello! I have a problem with using binary content of file. I want to pass web method content of file. I retriev it from fileupload control on my page via javascript function getAsBinary(). But error appears in web method, when I try to create example of class Image. So, I have the page (.aspx) with fileupload control and scriptmanager. There are three javascript function:

// Get image from fileupload control and pass it in webmethod
function Get_image() {
    var file_uploader = document.getElementById(file_uploader_name);
    var file_content = file_uploader.files[0].getAsBinary();
    imupcon.Get_image(file_content, OnRequestComplete, OnError);
}
// Successful execution
function OnRequestComplete(result) {alert(result);}
//Error execution
function OnError() { alert("Error!");}

And I have web-service with web-method:

[WebMethod]
public string Get_image(string file_content, string file_name) 
{
 byte[] data = Encoding.Unicode.GetBytes(file_content);
 MemoryStream memStream = new MemoryStream();
 memStream.Write(data, 0, data.Length);

 //Error appears here
 System.Drawing.Image image = System.Drawing.Image.FromStream(memStream);

 memStream.Close();
 return "Hurray!";
}

Does any have idea, what is reason? How I can pass content of file to web method? Thanks.

Answer 1

You don't need Encoding.Unicode.GetBytes if it's as it's already in binary. The data would be in unicode if you called files[0].getAsText("utf-8"). Please note that all of these methods are now obsolete and you should use feature detection and use the standard FileReader API if it is available.