Extensions
HKCU\Software\Microsoft\Windows NT\CurrentVersion
Description
The Extensions subkey stores entries that associate file name extensions with command line executions. These entries are used only when a file name extension is not already associated with a program.
Each of the entries in this subkey has the following format:
Entry name |
Data type |
Value |
|---|---|---|
File name extension |
REG_SZ |
Command line to run |
For example, the following entry indicates that, for all files with the extension .txt, the default action is to open the file with Microsoft Notepad:
Entry name |
Data type |
Value |
|---|---|---|
txt |
REG_SZ |
notepad.exe^.txt |
But, in this example, the entry indicates that the default action for all files with the extension .txt is to open the file with notepad and print it to the default printer. At run time, the caret symbol (^) is replaced with the name of the selected file in the command line:
Entry name |
Data type |
Value |
|---|---|---|
txt |
REG_SZ |
notepad.exe^.txt -openandprint |
Change method
To associate a file type with a program, use Windows Explorer. From the Tools menu, click Folder Options, and then click the File Types tab.
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Tip
For more information about creating a file association, see the Platform Software Development Kit (SDK) documentation in the MSDN Library at .