File input and Dart

I'm trying out Dart, but I cant figure out, how to send an image from the user to the server. I have my input-tag, and i can reach this in the DART code, but i cant seem to read from it. Im trying something like:

InputElement ie = document.query('#myinputelement');

ie.on.change.add((event){<br/>
    InputElement iee = document.query('#myinputelement');<br/>
    FileList mfl =  iee.files;<br/>
    File myFile = mlf.item(0);<br/>

    FileReader fr = new FileReader();
    fr.readAsBinaryString(myFile);

    String result = fr.result; //this is always empty
});

With the html containing:

<input type="file" id="myinputelement">

I really hope you cant help me, im kinda stuck. I might just be missing how to do the onload for the filereader, or maybe im doing it totally wrong.