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Read-only properties

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  • P PIEBALDconsult

    I just found a bunch of properties made read-only like this (I think they're from a template):

    set
    {
    // Do nothing
    }

    Huh? If you want it to be read-only, make it read-only! :mad:

    G Offline
    G Offline
    GibbleCH
    wrote on last edited by
    #3

    Actually, I have found that sometimes you need to do that. I can't remember the exact reasoning, but a couple weeks ago I was trying to pass a readonly property to a .NET function of some sort and it would throw an error, despite, the property not being written too...the "fix" was to have an empty set...and I believe I marked it as deprecated so it threw a compile error if someone tried to write to it.

    P 1 Reply Last reply
    0
    • G GibbleCH

      Actually, I have found that sometimes you need to do that. I can't remember the exact reasoning, but a couple weeks ago I was trying to pass a readonly property to a .NET function of some sort and it would throw an error, despite, the property not being written too...the "fix" was to have an empty set...and I believe I marked it as deprecated so it threw a compile error if someone tried to write to it.

      P Offline
      P Offline
      PIEBALDconsult
      wrote on last edited by
      #4

      The ObsoleteAttribute can't be applied to a property accessor. :( The class in question is implementing an abstract class, which specifies both get and set. I should have checked that before I posted this, but still... the set should throw a NotImplementedException or something. Failing that, the accessor should be functional.

      1 Reply Last reply
      0
      • P PIEBALDconsult

        I just found a bunch of properties made read-only like this (I think they're from a template):

        set
        {
        // Do nothing
        }

        Huh? If you want it to be read-only, make it read-only! :mad:

        D Offline
        D Offline
        darkelv
        wrote on last edited by
        #5

        Well, if the guy who owns the interface doesn't want to remove the set from the interface, I guess you are pretty much stucked with that.

        P 1 Reply Last reply
        0
        • D darkelv

          Well, if the guy who owns the interface doesn't want to remove the set from the interface, I guess you are pretty much stucked with that.

          P Offline
          P Offline
          PIEBALDconsult
          wrote on last edited by
          #6

          Yes, but silently ignoring the value is poor style.

          P 1 Reply Last reply
          0
          • P PIEBALDconsult

            I just found a bunch of properties made read-only like this (I think they're from a template):

            set
            {
            // Do nothing
            }

            Huh? If you want it to be read-only, make it read-only! :mad:

            B Offline
            B Offline
            BadKarma
            wrote on last edited by
            #7

            Still, its better then the following

            private int m_iData;
            public int Data
            {
             get 
             {
              return m_iData;
             }
             set
             {
               // store the old data
               //
               int iOldData = m_iData;
            
               m_iData = value;
            
               // reset to old data because its read-only
               //
               m_iData = iOldData
             }
            }
            

            codito ergo sum

            CPalliniC K F 3 Replies Last reply
            0
            • P PIEBALDconsult

              I just found a bunch of properties made read-only like this (I think they're from a template):

              set
              {
              // Do nothing
              }

              Huh? If you want it to be read-only, make it read-only! :mad:

              M Offline
              M Offline
              mav northwind
              wrote on last edited by
              #8

              You guys are so negative! Try to see the good in this approach. Using this approach one could perform consistency checks before not saving the value... :laugh:

              Regards, mav -- Black holes are the places where God divided by 0...

              G P 2 Replies Last reply
              0
              • B BadKarma

                Still, its better then the following

                private int m_iData;
                public int Data
                {
                 get 
                 {
                  return m_iData;
                 }
                 set
                 {
                   // store the old data
                   //
                   int iOldData = m_iData;
                
                   m_iData = value;
                
                   // reset to old data because its read-only
                   //
                   m_iData = iOldData
                 }
                }
                

                codito ergo sum

                CPalliniC Offline
                CPalliniC Offline
                CPallini
                wrote on last edited by
                #9

                :laugh:

                If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
                This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke

                In testa che avete, signor di Ceprano?

                1 Reply Last reply
                0
                • P PIEBALDconsult

                  Yes, but silently ignoring the value is poor style.

                  P Offline
                  P Offline
                  Paul Conrad
                  wrote on last edited by
                  #10

                  PIEBALDconsult wrote:

                  silently ignoring the value is poor style.

                  Yes, it is. I can only imagine the headache of trying to track it down on a Friday afternoon.

                  "The clue train passed his station without stopping." - John Simmons / outlaw programmer

                  D 1 Reply Last reply
                  0
                  • M mav northwind

                    You guys are so negative! Try to see the good in this approach. Using this approach one could perform consistency checks before not saving the value... :laugh:

                    Regards, mav -- Black holes are the places where God divided by 0...

                    G Offline
                    G Offline
                    GibbleCH
                    wrote on last edited by
                    #11

                    Alternately, if at some point in time, the property was to become (or maybe was in the past) not 'readonly', applications relying on the dll wouldn't necessarily need to be recompiled to use the new dll, since the definition wouldn't change...on that item.

                    L 1 Reply Last reply
                    0
                    • B BadKarma

                      Still, its better then the following

                      private int m_iData;
                      public int Data
                      {
                       get 
                       {
                        return m_iData;
                       }
                       set
                       {
                         // store the old data
                         //
                         int iOldData = m_iData;
                      
                         m_iData = value;
                      
                         // reset to old data because its read-only
                         //
                         m_iData = iOldData
                       }
                      }
                      

                      codito ergo sum

                      K Offline
                      K Offline
                      Krirk
                      wrote on last edited by
                      #12

                      Excellent code.A guy who wrote this code is genius. :omg: :wtf:X|

                      My blog

                      1 Reply Last reply
                      0
                      • G GibbleCH

                        Alternately, if at some point in time, the property was to become (or maybe was in the past) not 'readonly', applications relying on the dll wouldn't necessarily need to be recompiled to use the new dll, since the definition wouldn't change...on that item.

                        L Offline
                        L Offline
                        Lutoslaw
                        wrote on last edited by
                        #13

                        Yeach. And if some library user tried to write to a property and didn't notice that it took no effect, then after an upgrade his code could break because the old do-nothing setter would suddenly change something. :doh:

                        Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.

                        1 Reply Last reply
                        0
                        • P PIEBALDconsult

                          I just found a bunch of properties made read-only like this (I think they're from a template):

                          set
                          {
                          // Do nothing
                          }

                          Huh? If you want it to be read-only, make it read-only! :mad:

                          L Offline
                          L Offline
                          leppie
                          wrote on last edited by
                          #14

                          You need this scenario with XML deserialization.

                          xacc.ide - now with IronScheme support
                          IronScheme - 1.0 alpha 2 out now

                          P G 2 Replies Last reply
                          0
                          • L leppie

                            You need this scenario with XML deserialization.

                            xacc.ide - now with IronScheme support
                            IronScheme - 1.0 alpha 2 out now

                            P Offline
                            P Offline
                            PIEBALDconsult
                            wrote on last edited by
                            #15

                            Good point, but... Not if it's done right. I haven't done much serialization (XML or otherwise), but as I recall the class specifies which members get serialized and deserialized, so this shouldn't be a problem. You might have to override the base class' deserializer. Or I may just be showing my ignorance. :-O

                            L 1 Reply Last reply
                            0
                            • P Paul Conrad

                              PIEBALDconsult wrote:

                              silently ignoring the value is poor style.

                              Yes, it is. I can only imagine the headache of trying to track it down on a Friday afternoon.

                              "The clue train passed his station without stopping." - John Simmons / outlaw programmer

                              D Offline
                              D Offline
                              Derek Bartram
                              wrote on last edited by
                              #16

                              Well, personally I say get rid of properties anyway! There is simply no point in them other than making the language more bloated and less clear.... In the good old days.... .name = public class variable, didn't run any code, just gave access.... now will it run code, or won't it!?!?!??!?

                              P 1 Reply Last reply
                              0
                              • D Derek Bartram

                                Well, personally I say get rid of properties anyway! There is simply no point in them other than making the language more bloated and less clear.... In the good old days.... .name = public class variable, didn't run any code, just gave access.... now will it run code, or won't it!?!?!??!?

                                P Offline
                                P Offline
                                PIEBALDconsult
                                wrote on last edited by
                                #17

                                Sure they can be abused, but I wouldn't get rid of them just because of that.

                                D 1 Reply Last reply
                                0
                                • P PIEBALDconsult

                                  Sure they can be abused, but I wouldn't get rid of them just because of that.

                                  D Offline
                                  D Offline
                                  Derek Bartram
                                  wrote on last edited by
                                  #18

                                  Maybe, but it just seams like a lazy way of coding that means it's harder to tell what code is actually doing. Personally I feel it makes using other people's code harder (particularily badly written code where the property name is misleading)

                                  G 1 Reply Last reply
                                  0
                                  • D Derek Bartram

                                    Maybe, but it just seams like a lazy way of coding that means it's harder to tell what code is actually doing. Personally I feel it makes using other people's code harder (particularily badly written code where the property name is misleading)

                                    G Offline
                                    G Offline
                                    GibbleCH
                                    wrote on last edited by
                                    #19

                                    But properly written properties do data validation, and will modify any other values that need to be modified when that property changes.

                                    D 1 Reply Last reply
                                    0
                                    • L leppie

                                      You need this scenario with XML deserialization.

                                      xacc.ide - now with IronScheme support
                                      IronScheme - 1.0 alpha 2 out now

                                      G Offline
                                      G Offline
                                      GibbleCH
                                      wrote on last edited by
                                      #20

                                      THAT'S IT! That's why I had to do something similar to this coding horror.

                                      1 Reply Last reply
                                      0
                                      • G GibbleCH

                                        But properly written properties do data validation, and will modify any other values that need to be modified when that property changes.

                                        D Offline
                                        D Offline
                                        Derek Bartram
                                        wrote on last edited by
                                        #21

                                        That's the problem though... the amount of people who i've seen doing things like modify data structures in property gets, is pretty high. Why leave elements of the language that can result in really hard to debug code and misconceptions?

                                        G J 2 Replies Last reply
                                        0
                                        • D Derek Bartram

                                          That's the problem though... the amount of people who i've seen doing things like modify data structures in property gets, is pretty high. Why leave elements of the language that can result in really hard to debug code and misconceptions?

                                          G Offline
                                          G Offline
                                          GibbleCH
                                          wrote on last edited by
                                          #22

                                          But, often, if you don't modify the data of the class, when you set the property, your data may be invalid...and calling functionX at that time will result in invalid results, or errors.

                                          D 1 Reply Last reply
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