Qt Linguist清除无效翻译

{Your_Qt_Path}/bin/lupdate.exe {Your_Project_Path}/{Your_Project_Name}.pro -noobsolete

附命令帮助：

lupdate

Usage:
    lupdate [options] [project-file]
    lupdate [options] [source-file|path]... -ts ts-files
Options:
    -help  Display this information and exit.
    -noobsolete
           Drop all obsolete strings.
    -extensions [,]...
           Process files with the given extensions only.
           The extension list must be separated with commas, not with whitespace.
           Default: 'ui,c,c++,cc,cpp,cxx,ch,h,h++,hh,hpp,hxx'.
    -pluralonly
           Only include plural form messages.
    -silent
           Do not explain what is being done.
    -version
           Display the version of lupdate and exit.

lrelease

Usage:
    lrelease [options] project-file
    lrelease [options] ts-files [-qm qm-file]
lrelease is part of Qt's Linguist tool chain. It can be used as a
stand-alone tool to convert XML-based translations files in the TS
format into the 'compiled' QM format used by QTranslator objects.
Options:
    -help  Display this information and exit
    -idbased
           Use IDs instead of source strings for message keying
    -compress
           Compress the QM files
    -nounfinished
           Do not include unfinished translations
    -removeidentical
           If the translated text is the same as
           the source text, do not include the message
    -markuntranslated 
           If a message has no real translation, use the source text
           prefixed with the given string instead
    -silent
           Do not explain what is being done
    -version
           Display the version of lrelease and exit