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how to use the elements that is not belong in your class

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  • dheerendraD Offline
    dheerendraD Offline
    dheerendra
    Moderators Qt Champions 2024 Qt Champions 2022 Qt Champions 2017
    wrote on last edited by
    #2

    This question is nothing to do with qt. please check on how to use static class variables in c++. Declare cannum variable as static in main window class and use it. Why do u want to do this ?

    Dheerendra
    @Community Service
    Certified Qt Specialist
    https://www.pthinks.com

    V 2 Replies Last reply
    1
    • dheerendraD dheerendra

      This question is nothing to do with qt. please check on how to use static class variables in c++. Declare cannum variable as static in main window class and use it. Why do u want to do this ?

      V Offline
      V Offline
      victor wang
      wrote on last edited by
      #3

      @dheerendra
      I want to using the specific String that i will give it in the MainWindow and used it in my CandumThread class.

      Is this will cause any problem?

      1 Reply Last reply
      0
      • dheerendraD dheerendra

        This question is nothing to do with qt. please check on how to use static class variables in c++. Declare cannum variable as static in main window class and use it. Why do u want to do this ?

        V Offline
        V Offline
        victor wang
        wrote on last edited by
        #4

        @dheerendra
        Do you have any suggestion to do it better?
        cause i don't want cannum to be the static String cause i will need to change the value in the MainWindow if i need.

        1 Reply Last reply
        0
        • dheerendraD Offline
          dheerendraD Offline
          dheerendra
          Moderators Qt Champions 2024 Qt Champions 2022 Qt Champions 2017
          wrote on last edited by dheerendra
          #5

          When are u assigning this string value ? Just check how static variable work in c++. It should help.

          Dheerendra
          @Community Service
          Certified Qt Specialist
          https://www.pthinks.com

          V 1 Reply Last reply
          1
          • dheerendraD dheerendra

            When are u assigning this string value ? Just check how static variable work in c++. It should help.

            V Offline
            V Offline
            victor wang
            wrote on last edited by
            #6

            @dheerendra
            I will assigned it in the MainWindow.
            And i will want to used it at CandumpThread.

            i change ti into static const and still not work.

            jsulmJ 2 Replies Last reply
            0
            • V victor wang

              @dheerendra
              I will assigned it in the MainWindow.
              And i will want to used it at CandumpThread.

              i change ti into static const and still not work.

              jsulmJ Offline
              jsulmJ Offline
              jsulm
              Lifetime Qt Champion
              wrote on last edited by
              #7

              @victor-wang If MainWindow is using CandumpThread then just pass that string from MainWindow to CandumpThread constructor.
              Don't make cannum static! Your CandumpThread class should not know anything about MainWindow (it would be bad design if it would know).

              https://forum.qt.io/topic/113070/qt-code-of-conduct

              1 Reply Last reply
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              • V victor wang

                @dheerendra
                I will assigned it in the MainWindow.
                And i will want to used it at CandumpThread.

                i change ti into static const and still not work.

                jsulmJ Offline
                jsulmJ Offline
                jsulm
                Lifetime Qt Champion
                wrote on last edited by
                #8

                @victor-wang I moved this thread to "C++ gurus" forum as your question is not related to Qt but to C++.

                https://forum.qt.io/topic/113070/qt-code-of-conduct

                V 1 Reply Last reply
                0
                • jsulmJ jsulm

                  @victor-wang I moved this thread to "C++ gurus" forum as your question is not related to Qt but to C++.

                  V Offline
                  V Offline
                  victor wang
                  wrote on last edited by
                  #9

                  @jsulm
                  Thx a lot!
                  I have solve the problem.
                  I add this program.

                  DIDOThread::DIDOThread(QObject *parent) : QThread(parent)
                  {
                      p = (MainWindow *)parent;
                  }
                  
                  

                  It work for me in my DIDOThread class!

                  jsulmJ 1 Reply Last reply
                  0
                  • V victor wang

                    @jsulm
                    Thx a lot!
                    I have solve the problem.
                    I add this program.

                    DIDOThread::DIDOThread(QObject *parent) : QThread(parent)
                    {
                        p = (MainWindow *)parent;
                    }
                    
                    

                    It work for me in my DIDOThread class!

                    jsulmJ Offline
                    jsulmJ Offline
                    jsulm
                    Lifetime Qt Champion
                    wrote on last edited by
                    #10

                    @victor-wang Bad design...
                    You should instead pass the string as parameter:

                    DIDOThread::DIDOThread(const QString &cannum, QObject *parent) : QThread(parent)
                    {
                        
                    }
                    

                    And if you still want to do it like you shown then you should at least use C++ style cast not C.

                    https://forum.qt.io/topic/113070/qt-code-of-conduct

                    V 1 Reply Last reply
                    1
                    • jsulmJ jsulm

                      @victor-wang Bad design...
                      You should instead pass the string as parameter:

                      DIDOThread::DIDOThread(const QString &cannum, QObject *parent) : QThread(parent)
                      {
                          
                      }
                      

                      And if you still want to do it like you shown then you should at least use C++ style cast not C.

                      V Offline
                      V Offline
                      victor wang
                      wrote on last edited by
                      #11

                      @jsulm
                      You mean i can add this program in my DIDOThread.h file?

                      jsulmJ 1 Reply Last reply
                      0
                      • V victor wang

                        @jsulm
                        You mean i can add this program in my DIDOThread.h file?

                        jsulmJ Offline
                        jsulmJ Offline
                        jsulm
                        Lifetime Qt Champion
                        wrote on last edited by
                        #12

                        @victor-wang Yes, you just add "const QString &cannum" to your constructor in DIDOThread as I shown.

                        https://forum.qt.io/topic/113070/qt-code-of-conduct

                        1 Reply Last reply
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