How Windows Manages File Actions with Associations
In the Registry is a list of file types that are registered for a specific computer. The list contains what actions are possible for that particular file, which software is supposed to carry out the action, and where on the computer that software is located (the path). All file types will have at least one possible action called the Default. Many file types may have several possible actions, often using different software. The Default action is the one that double left-clicking brings about. When more than one action is possible for a file type, Open is usually the Default, but any of the possible actions can be made the Default. When a user invokes a particular file by double-clicking, the operating system consults the Registry and from the listed path for the Default action calls up the appropriate executable software file to carry out the desired action. For example, one particular program will be assigned or associated to Open (display) any hypertext document with the extension htm . In addition, a different program might be associated to htm files for an action denoted Edit . This action would show the actual HTML code rather than the compiled page and would allow changing the code. Thus, Internet Explorer or other browser (the "default" browser if you have more than one) would be used to Open , but Notepad or FrontPage or other HTML editor would be involved in Edit . Note that a choice of two or more different programs to do the same action is possible as long as different names are given to the choices.
In
general, actions other than the Default are invoked from the right-click
context menu. Right-clicking a file once (there is normally no double click
action defined for the right mouse button) will bring up a list of things
(called the context menu ). The top portion of the menu shows all
the possible actions for the file, including the Default, which will be in
boldface. An example of the top portion of a context menu is shown in the
graphic on the left. The default action here is the typical "Open".
This example file is an HTML file and "Open' will
cause Internet Explorer to display the file. There is also an entry "Edit".
In this case that will cause Microsoft Word to open the file for editing.
However, if preferred, there are entries so that the file can be edited with
Notepad or with Dreamweaver instead. A single click (left or right) on any
one of the entries in the menu will bring about the indicated action. (Remember
the click sequence, one click from the right on the file icon or listing,
then one from the left or right on a listed action within the context menu.
People who have problems double-clicking can open files this way.)