Working with the visual parts
Building an application with the Web Connection feature follows the same basic process as building any VA Smalltalk application, but with some differences. Chiefly, these differences fall into the following categories:
•A smaller set of visual parts. In a Web application, you can use only the visual parts in the Web Connection category. These parts represent the user-interface controls and other page elements that are supported by most Web browsers.
•Different placement behavior in the Composition Editor. The placement and alignment of the elements on a Web page are handled by the Web browser and are not under the control of the developer. The visual parts in the Web Connection category reflect this by arranging themselves in approximately the way they would appear when rendered in a Web browser. Most of the part placement and alignment functions of the Composition Editor do not function when you edit a Web page. In addition, most of the visual parts are not resizable; generally, size is determined by the browser based upon the element content.
Placement of the parts within the page adheres to a scheme called flowed layout, which mirrors the linear way in which HTML is transmitted to the browser for rendering. In flowed layout, visual parts are always arranged from upper left to lower right, as they would be rendered in a Web browser. This arrangement provides an approximation of how your page will look, but remember that what you see in the Composition Editor may not be the same as what your users see in their browsers.
•Differences in application flow. In a typical VA Smalltalk application, events driving application execution (such as button clicks or other user actions) can happen at any time and can dynamically change what appears on the screen. A Web application, however, consists of a series of static windows, each processing the input from the previous window.
Last modified date: 01/29/2015