c# - How to add value-less HTML5 attributes from code-behind -

this follow of question: how add <audio> tag content of page in code behind?

here creating audio control this.

var myaudio = new system.web.ui.htmlcontrols.htmlaudio(); myaudio.attributes.add("autoplay", "autoplay"); myaudio.attributes.add("controls", "controls"); myaudio.src = "test.mp3"; form.controls.add(myaudio); 

this renders in page as

<audio src="test.mp3" autoplay="autoplay" controls="controls"></audio> 

it works. ideally, rendered

<audio src="test.mp3" autoplay controls></audio> 

that is, valueless attribute keys autoplay , controls.

i tried

myaudio.attributes.add("autoplay", ""); //autoplay = ""; myaudio.attributes.add("autoplay", null); //autoplay attribute missing 

but these didn't yield satisfactory results.

is there way render control valueless attributes?

a possible solution override renderattributes method on inherited control.

public class mycustomaudio : system.web.ui.htmlcontrols.htmlaudio {     protected override void renderattributes(htmltextwriter writer)     {         foreach (string key in this.attributes.keys)         {             string val = this.attributes[key];             writer.write(val == key                 ? string.format(" {0}", key)                 : string.format(" {0}=\"{1}\"", key, val));         }     } } 

with same code:

var myaudio = new mycustomaudio(); myaudio.attributes.add("autoplay", "autoplay"); myaudio.attributes.add("controls", "controls"); myaudio.src = "test.mp3"; form.controls.add(myaudio); 

i got output:

<audio autoplay controls src="test.mp3"></audio>