How do I customize the file name extension?

A lot of files you want to open, will pop up "open mode" dialog box, of course, the commonly used file types will automatically help you choose and open, in order to save this trouble we have the following choices:

1. Right-click the file, select Properties, and navigate to the General tab

Then click the Change ... button to select the application you want to use as the default open mode.

2. Modify the Registration Form

Run regedit

Add a key to the extension, such as HKEY_CLASSES_ROOT.TTTT, whose value is the entry key to which it is associated

Add entry key as the associated application Hkey_classes_roottestshellopencommand, whose value is: "Path to. exe" "1%"

Note: The meaning of%1,%2,%3,%4 in the registry

This is the default variable in the system and, in different cases, the meaning is different. Typically,% 1 represents the operating file,%2 represents the system default printer,%3 indicates the data sector, and%4 indicates port.

For example, for. TXT file, in the registry about its default open way to the point is:%systemroot%system32notepad.exe%1 Here,%1 represents the current. TXT file is passed as a variable to the NOTEPAD.EXE program to open. Quotes are added in order to pass in parameters with spaces.