Custom sort algorithm

Chan — Mon, 05 May 2008 10:11:31 GMT

Hi,
I have item as below:



ItemName          BeforeItem    AfterItem

------------------------------------------

"First"

"Second"

"Third"

"B4Second"        "Second"

"BetweenSecond"   "Second"      "B4Second"

I would like to implement IComparable to sort them so that it could be as below:

First
B4Second
BetweenSecond
Second
Third

Please advice

Thank you

RE: Custom sort algorithm

Trent L. Taylor — Mon, 05 May 2008 10:11:31 GMT

Here is a quick sample of how to create a collection and the sort the collection with an IComparer class. This should get you going in the right direction:

[codesnippet]

''' <summary>
''' Create a generic collection that houses the MyItem class in a collection
''' </summary>
''' <remarks></remarks>
Public Class MyCollection
Inherits System.Collections.CollectionBase

    Public Sub Add(ByVal item As MyItem)
        InnerList.Add(item)
    End Sub

    ''' <summary>
    ''' Use the IComparer class that we created to sort the list
    ''' </summary>
    ''' <remarks></remarks>
    Public Sub Sort()
        Dim sorter As New MySort()
        InnerList.Sort(sorter)
    End Sub
End Class

''' <summary>
''' Create the sorter to accept a MyItem class and then sort on the MyValue within the class
''' </summary>
''' <remarks></remarks>
Public Class MySort
Implements System.Collections.IComparer

    ''' <summary>
    ''' Compare the two MyValue strings. If you want to produce a descending sort, then reverse the x and y values.
    ''' </summary>
    ''' <param name="x"></param>
    ''' <param name="y"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements System.Collections.IComparer.Compare
        Return String.Compare(DirectCast(x, MyItem).MyValue, DirectCast(y, MyItem).MyValue)
    End Function

End Class

Public Class MyTest

Private _Items As New MyCollection()

Private Sub TestSort()
    _Items.Add(New MyItem("Orange"))
    _Items.Add(New MyItem("Apple"))
    _Items.Add(New MyItem("Pear"))
    _Items.Add(New MyItem("Grapes"))
    _Items.Add(New MyItem("Banana"))

'-- Sort the collection
_Items.Sort()

End Sub

End Class

[/codesnippet]

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Custom sort algorithm

RE: Custom sort algorithm