Creating a New File Type
Windows XP comes with a long list of registered file types, but it can’t account for every extension you’ll face in your computing career. For rare extensions, it’s best just to use the Open With dialog box. However, if you have an unregistered extension that you encounter frequently, you should register that extension by creating a new file type for it. The next two sections provide a couple of methods for doing this.
Using Open With to Create a Basic File Type
Our old friend the Open With dialog box provides a quick-and-dirty method for creating a simple file type for an unregistered extension:
In Windows Explorer, select the file you want to work with.
Select File, Open. (For unregistered file types, Windows XP doesn’t display the Open With command.) Windows XP displays a dialog box telling you that it cannot open the file, as shown in Figure 3.9.
Activate the Select the Program from a List option and then click OK. The Open With dialog box appears.
In the Programs list, select the application you want to use to open the file or click Browse to choose the program from a dialog box.
Use the Type a Description That You Want to Use for This Kind of File text box to enter a description for the new file type.
Make sure that the Always Use the Selected Program to Open This Kind of File check box is activated.
Figure 3.9 Windows XP displays this dialog box when you attempt to open an unregistered file type.
This method creates a new file type with the following properties:
In the File Types tab, the new file type appears in the Registered File Types list under the name you entered into the Type a Description type box.
The number of actions Windows XP creates for the file type depends on the application you selected. If you can use the application to both display and edit the file, Windows XP creates Open and Edit actions; if you can use the application only to display the file, Windows XP creates just the Open action.
The icon associated with the file is the same as the one used by the associated application.
In the Registry, the new HKEY_CLASSES_ROOT file type name is ext_auto_file, where ext is the file’s extension.
Using the File Types Tab to Create a More Advanced File Type
If you want more control over your new file type, use the File Types tab instead of the Open With dialog box. This method enables you to select a different icon, set up multiple actions, and more. Here are the steps to follow:
Open the Folder Options dialog box and display the File Types tab.
Click New. Windows XP displays the Create New Extension dialog box shown in Figure 3.10.
Type the File Extension for the new file type.
Click OK to return to the File Types tab.
Select the new extension in the Registered File Types list.
Click Advanced to display the Edit File Type dialog box.
Change the file type description and icon, if desired. Follow the steps I outlined in the "Creating a New File Type Action" section to create an Open action for the new file type, as well as any other actions you require (such as Edit or Print).
Figure 3.10 Use the Create New Extension dialog box to define your new file type.