how to drag and drop using (c#,asp.net)any color in any particular shape like triangle,circle,rectengle etc.

If you try to solve this problem in ASP.NET (meaning: on the server part), you will have to perform so frequent postbacks, that it will slow down operation too much. Rather, you need to do it all on client side. I would advise to use HTML5 canvas, via JavaScript:
http://en.wikipedia.org/wiki/HTML5_canvas[^],
http://www.w3.org/TR/2009/WD-html5-20090825/the-canvas-element.html[^],
https://developer.apple.com/library/mac/documentation/AppleApplications/Conceptual/SafariJSProgTopics/Tasks/Canvas.html[^],
http://dev.opera.com/articles/view/html-5-canvas-the-basics/[^],
https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Canvas_tutorial?redirectlocale=en-US&redirectslug=Canvas_tutorial[^].

Please see how impressive the interactive canvas graphics can be: http://net.tutsplus.com/articles/web-roundups/21-ridiculously-impressive-html5-canvas-experiments[^].

—SA