Creating Aspnet Server Controls by Drag Drop

Hi Guys,

Im working on an app where Users can drag and Drop controls on forms.The problem is they are not html controls( like HtmlINput or Textbox), they are server controls.The application is basically designing the forms on the fly.
There is a right panel from Where Users can drag and drop the controls on Right Container. Now they are essentially ASP.net Server controls like Textbox,radio button checkboxes etc.
What i want is that when user drags the controls from right pan and releases it to left, new controls should get added on left pane something like:-

If Ondrag(RightPane)->ReleaseOn(LeftPane) then
OnRelaseOnRightPane = new Asp.netServerControl

The server controls im adding from a class library. That is if someone drags and drops a textbox, then objTextBox will be reutrned. Then that textbox will be added to the pane.

jotform.com

Is there any way through which i can use JS to drag a control and then execute some server method that will return me an object which i can crate on my form?

My issue is only one thing, How can i accomplish drag and drop. See these are not static container where i can move my already created controls. I want to create a new control.Morever these are server controls that i want to add.

I tried web parts but no support and not good enough
With javascript i have used drag drop scripts from dhtmlgoodies, but no use

Can anybody help me out with any sugegstion or approach ?

Build your controls as WebParts to help make the drag/drop easier.

Quite easy to think of....but not good enough.....if i start so, i can complete my entire application before i'll complete making webparts like controls...any other sugegstions?