@echo off
setlocal enabledelayedexpansion
set "ext=%~x1"
:loop
if defined ext set "ext=!ext:"=!"
if defined ext goto ok
echo 如果你不知道文件的扩展名，关闭批处理然后把文件拖到批处理文件的图标上。
set /p "v=请输入扩展名（如txt）然后回车："
for /f "delims=" %%i in (".!v!") do set "ext=%%~xi"
goto loop
:ok
echo 扩展名：!ext!
pause
reg delete "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\!ext!" /f
reg query "HKCR\!ext!" /ve|find /i "!ext:~1!_auto_file">nul
if not errorlevel 1 (
reg delete "HKCR\!ext!" /ve /f
reg delete "HKCR\!ext:~1!_auto_file" /f
)
taskkill /im explorer.exe /f
start %windir%\explorer.exe
pause
goto :eof