Sort descending using IComparable ?

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  • John Devlon
    #1

    Sort descending using IComparable ?

    Hi everyone,

    With this post I would like to ask you all a small question.

    I'm trying to sort an array of objects using IComparable. Adding below
    displayed code to a class and triggering the sort function works fine. Thats
    not the problem.

    The only thing I would like to change is: I would like sort the Name
    descending (starting with the z)...
    Does anyone know how ?

    Many Thanx

    John

    Ps: using VB.NET 2005


    Code:

    Public Function CompareTo(ByVal myPerson As clsPerson) As Integer Implements
    System.ICompara ble(Of clsPerson).Comp areTo
    If Me.Language = myPerson.Langua ge Then
    If Me.City = myPerson.City Then
    Return Me.Name.Compare To(myPerson.Nam e)
    Else
    Return Me.City.Compare To(myPerson.Cit y)
    End If
    Else
    Return Me.Language.Com pareTo(myPerson .Language)
    End If

    End Function


    Tags: None
    • Mr. Arnold
      #2
      Re: Sort descending using IComparable ?


      "John Devlon" <johndevlon@hot mail.comwrote in message
      news:mJ7bi.6705 $QZ3.808180@pho bos.telenet-ops.be...
      Hi everyone,
      >
      With this post I would like to ask you all a small question.
      >
      I'm trying to sort an array of objects using IComparable. Adding below
      displayed code to a class and triggering the sort function works fine.
      Thats not the problem.
      >
      The only thing I would like to change is: I would like sort the Name
      descending (starting with the z)...
      Does anyone know how ?
      >
      >
      The link talks about Array.Sort and then Array.Reverse.

      http://samples.gotdotnet.com/quickstart/howto/doc/sort.aspx


      The link talks about Key/Item pairs sorting.

      Array.Sort Method (System)
      http://msdn2.microsoft.com/en-us/library/system.array.sort(vs.80).aspx
      Sorts the elements in a one-dimensional array.


        Comment

        • Kelly Ethridge
          #3
          Re: Sort descending using IComparable ?

          Hello,

          Just return the opposite sign of the comparison.

          Public Function CompareTo(ByVal myPerson As clsPerson) As Integer
          Implements System.ICompara ble(Of clsPerson).Comp areTo
          Dim result As Integer

          If Me.Language = myPerson.Langua ge Then
          If Me.City = myPerson.City Then
          result = Me.Name.Compare To(myPerson.Nam e)
          Else
          result = Me.City.Compare To(myPerson.Cit y)
          End If
          Else
          result = Me.Language.Com pareTo(myPerson .Language)
          End If

          Return -result ' return opposite
          End Function

          John Devlon wrote:
          Hi everyone,
          >
          With this post I would like to ask you all a small question.
          >
          I'm trying to sort an array of objects using IComparable. Adding below
          displayed code to a class and triggering the sort function works fine. Thats
          not the problem.
          >
          The only thing I would like to change is: I would like sort the Name
          descending (starting with the z)...
          Does anyone know how ?
          >
          Many Thanx
          >
          John
          >
          Ps: using VB.NET 2005
          >
          >
          Code:
          >
          Public Function CompareTo(ByVal myPerson As clsPerson) As Integer Implements
          System.ICompara ble(Of clsPerson).Comp areTo
          If Me.Language = myPerson.Langua ge Then
          If Me.City = myPerson.City Then
          Return Me.Name.Compare To(myPerson.Nam e)
          Else
          Return Me.City.Compare To(myPerson.Cit y)
          End If
          Else
          Return Me.Language.Com pareTo(myPerson .Language)
          End If
          >
          End Function
          >
          >

            Comment

            • Kelly Ethridge
              #4
              Re: Sort descending using IComparable ?

              Hello again,

              I replied to quickly without realizing you only wanted to change the
              sorting order of the Name property. Just return the opposite for the
              Name comparison only.

              Public Function CompareTo(ByVal myPerson As clsPerson) As Integer
              Implements System.ICompara ble(Of clsPerson).Comp areTo
              If Me.Language = myPerson.Langua ge Then
              If Me.City = myPerson.City Then
              Return -Me.Name.Compare To(myPerson.Nam e) ' return opposite
              Else
              Return Me.City.Compare To(myPerson.Cit y)
              End If
              Else
              Return Me.Language.Com pareTo(myPerson .Language)
              End If
              End Function


              John Devlon wrote:
              Hi everyone,
              >
              With this post I would like to ask you all a small question.
              >
              I'm trying to sort an array of objects using IComparable. Adding below
              displayed code to a class and triggering the sort function works fine. Thats
              not the problem.
              >
              The only thing I would like to change is: I would like sort the Name
              descending (starting with the z)...
              Does anyone know how ?
              >
              Many Thanx
              >
              John
              >
              Ps: using VB.NET 2005
              >
              >
              Code:
              >
              Public Function CompareTo(ByVal myPerson As clsPerson) As Integer Implements
              System.ICompara ble(Of clsPerson).Comp areTo
              If Me.Language = myPerson.Langua ge Then
              If Me.City = myPerson.City Then
              Return Me.Name.Compare To(myPerson.Nam e)
              Else
              Return Me.City.Compare To(myPerson.Cit y)
              End If
              Else
              Return Me.Language.Com pareTo(myPerson .Language)
              End If
              >
              End Function
              >
              >

                Comment

                • John Devlon
                  #5
                  Re: Sort descending using IComparable ?


                  Dear Ms Ethridge,

                  Your absolutely amazing. It works perfect. Your the best.
                  How can I ever repay you ?

                  Kind regards,

                  John




                  "Kelly Ethridge" <kelly@kellyeth ridge.comwrote in message
                  news:uiP$xDCrHH A.1200@TK2MSFTN GP04.phx.gbl...
                  Hello again,
                  >
                  I replied to quickly without realizing you only wanted to change the
                  sorting order of the Name property. Just return the opposite for the Name
                  comparison only.
                  >
                  Public Function CompareTo(ByVal myPerson As clsPerson) As Integer
                  Implements System.ICompara ble(Of clsPerson).Comp areTo
                  If Me.Language = myPerson.Langua ge Then
                  If Me.City = myPerson.City Then
                  Return -Me.Name.Compare To(myPerson.Nam e) ' return opposite
                  Else
                  Return Me.City.Compare To(myPerson.Cit y)
                  End If
                  Else
                  Return Me.Language.Com pareTo(myPerson .Language)
                  End If
                  End Function
                  >
                  >
                  John Devlon wrote:
                  >Hi everyone,
                  >>
                  >With this post I would like to ask you all a small question.
                  >>
                  >I'm trying to sort an array of objects using IComparable. Adding below
                  >displayed code to a class and triggering the sort function works fine.
                  >Thats not the problem.
                  >>
                  >The only thing I would like to change is: I would like sort the Name
                  >descending (starting with the z)...
                  >Does anyone know how ?
                  >>
                  >Many Thanx
                  >>
                  >John
                  >>
                  >Ps: using VB.NET 2005
                  >>
                  >>
                  >Code:
                  >>
                  >Public Function CompareTo(ByVal myPerson As clsPerson) As Integer
                  >Implements System.ICompara ble(Of clsPerson).Comp areTo
                  > If Me.Language = myPerson.Langua ge Then
                  > If Me.City = myPerson.City Then
                  > Return Me.Name.Compare To(myPerson.Nam e)
                  > Else
                  > Return Me.City.Compare To(myPerson.Cit y)
                  > End If
                  > Else
                  > Return Me.Language.Com pareTo(myPerson .Language)
                  > End If
                  >>
                  >End Function

                    Comment

                    • John Devlon
                      #6
                      Re: Sort descending using IComparable ?

                      Dear Mr. Arnold,

                      Many thanx for the usefull links...

                      Kind regards

                      John


                      "Mr. Arnold" <MR. Arnold@Arnold.c omwrote in message
                      news:ekpjgVBrHH A.192@TK2MSFTNG P02.phx.gbl...
                      >
                      "John Devlon" <johndevlon@hot mail.comwrote in message
                      news:mJ7bi.6705 $QZ3.808180@pho bos.telenet-ops.be...
                      >Hi everyone,
                      >>
                      >With this post I would like to ask you all a small question.
                      >>
                      >I'm trying to sort an array of objects using IComparable. Adding below
                      >displayed code to a class and triggering the sort function works fine.
                      >Thats not the problem.
                      >>
                      >The only thing I would like to change is: I would like sort the Name
                      >descending (starting with the z)...
                      >Does anyone know how ?
                      >>
                      >>
                      >
                      The link talks about Array.Sort and then Array.Reverse.
                      >
                      http://samples.gotdotnet.com/quickstart/howto/doc/sort.aspx

                      >
                      The link talks about Key/Item pairs sorting.
                      >
                      http://msdn2.microsoft.com/en-us/lib...rt(vs.80).aspx

                        Comment

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