ASP.NET Dialog Window
The ASP.NET AJAX dialog window control is designed to replicate the functionality of a standard Windows Forms dialog box, allowing popup of both modal and non-modal dialogs in-browser that show all common dialog behaviors.DOWNLOAD ASP.NET Samples
Modal or Modeless
The WebDialogWindow lets you determine whether the dialog behaves as a modal or modeless dialog, providing better control over the flow of your application.
Display a customizable header area, insert caption text and several buttons including the close, minimize, and maximize buttons seen in desktop applications.
Enable your end user to resize the WebDialogWindow at run-time, just like a resizable dialog on the desktop.
WebDialogWindow persists whether the user has minimized, restored, or maximized its appearance.