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Sorting ListView by multiple columns in C #

With the controls, ListView

you can specify the column to sort, as well as the method sort()

whenever you want.

However, this only allows sorting by one column.

I try to sort, say first column A and then column F if they are the same.

I found several custom comparison classes written online, but wondered if stackoverflow could show a cleaner way. Also, it might help others looking for it in the future :)

Any suggestions or examples on how to do this are appreciated.

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So, after the game, I came up with a proposal to write a class ListViewItemComparer

through an interface IComparer

.

Then I overwritten the method Compare()

and could now return -1, 0, or 1 depending on the comparison of the first primary column and then when the secondary column is equal.



Quite possibly in the end, I think.

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As with almost all tasks, ObjectListView (an open source wrapper around the .NET WinForms ListView) makes life a lot easier with a ListView.

ObjectListView has properties SecondarySortColumn

and SecondarySortOrder

to do what you ask.



If you want to make sorting even more convenient, you can install CustomSorter

. Check out this recipe

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@MarkMayo, I created my own sorter class ListViewItemComparer

via an interface IComparer

that supports sorting secondary / priority columns.

I am rewriting the method Compare()

to support string comparison, date comparison and case insensitivity.

You will first sort the desired column, if both values ​​being compared are the same, the second column will be used for sorting and therefore secondary sorting.

You just need to enable this sorter class and change the Form Listview event ColumnClick

with the following VB.Net sample code:

ListViewItemComparer Class

Imports System.Collections

''' <summary>
''' This class is an implementation of the 'IComparer' interface.
''' </summary>
Public Class ListViewColumnSorter
    Implements IComparer
    ''' <summary>
    ''' Specifies the column to be sorted
    ''' </summary>
    Private ColumnToSort As Integer
    ''' <summary>
    ''' Specifies the secondary column to be sorted
    ''' </summary>
    Private SecondaryColumnToSort As Integer = -1
    ''' <summary>
    ''' Specifies the order in which to sort (i.e. 'Ascending').
    ''' </summary>
    Private OrderOfSort As SortOrder
    ''' <summary>
    ''' Class constructor. Initializes various elements
    ''' </summary>
    Public Sub New(ByVal column_number As Integer, ByVal sort_order As SortOrder)
        ColumnToSort = column_number
        OrderOfSort = sort_order
    End Sub
    ''' <summary>
    ''' Class constructor. Initializes various elements
    ''' </summary>
    Public Sub New(ByVal column_number As Integer, ByVal sort_order As SortOrder, ByVal secondary_column_number As Integer)
        ColumnToSort = column_number
        SecondaryColumnToSort = secondary_column_number
        OrderOfSort = sort_order
    End Sub

    ''' <summary>
    ''' This method is inherited from the IComparer interface. It compares the two objects passed and support secondary column comparison
    ''' </summary>
    ''' <param name="x">First object to be compared</param>
    ''' <param name="y">Second object to be compared</param>
    ''' <returns>The result of the comparison. "0" if equal, negative if 'x' is less than 'y' and positive if 'x' is greater than 'y'</returns>
    Public Function Compare(x As Object, y As Object) As Integer Implements IComparer.Compare
        Dim compareResult As Integer
        Dim listviewX As ListViewItem, listviewY As ListViewItem

        ' Cast the objects to be compared to ListViewItem objects
        listviewX = DirectCast(x, ListViewItem)
        listviewY = DirectCast(y, ListViewItem)

        ' Compare the two items
        Dim x1 As Object = listviewX.SubItems(ColumnToSort)
        Dim y1 As Object = listviewY.SubItems(ColumnToSort)

        ' Use .tag for comparison if not empty
        If (x1.Tag IsNot vbNullString) And (y1.Tag IsNot vbNullString) Then
            compareResult = ObjectComparer(x1.Tag, y1.Tag)
        Else
            compareResult = ObjectComparer(x1.Text, y1.Text)
        End If

        'require secondary column compare?
        If (compareResult = 0 And SecondaryColumnToSort >= 0 And SecondaryColumnToSort <> ColumnToSort) Then
            ' Compare the two items
            Dim x2 As Object = listviewX.SubItems(SecondaryColumnToSort)
            Dim y2 As Object = listviewY.SubItems(SecondaryColumnToSort)

            ' Use .tag for comparison if not empty
            If (x2.Tag IsNot vbNullString) And (y2.Tag IsNot vbNullString) Then
                compareResult = ObjectComparer(x2.Tag, y2.Tag)
            Else
                compareResult = ObjectComparer(x2.Text, y2.Text)
            End If
        End If

        ' Calculate correct return value based on object comparison
        If OrderOfSort = SortOrder.Ascending Then
            ' Ascending sort is selected, return normal result of compare operation
            Return compareResult
        ElseIf OrderOfSort = SortOrder.Descending Then
            ' Descending sort is selected, return negative result of compare operation
            Return (-compareResult)
        Else
            ' Return '0' to indicate they are equal
            Return 0
        End If
    End Function

    ''' <summary>
    ''' This method compares the two objects passed. Object supported are numeric, dates and string
    ''' </summary>
    ''' <param name="x">First object to be compared</param>
    ''' <param name="y">Second object to be compared</param>
    ''' <returns>The result of the comparison. "0" if equal, negative if 'x' is less than 'y' and positive if 'x' is greater than 'y'</returns>
    Private Function ObjectComparer(x As Object, y As Object) As Integer
        Dim compareResult As Integer

        If IsNumeric(x) And IsNumeric(y) Then 'comparing numbers
            compareResult = Val(x).CompareTo(Val(y))
        ElseIf IsDate(x) And IsDate(y) Then 'comparing dates
            compareResult = DateTime.Parse(x).CompareTo(DateTime.Parse(y))
        Else 'comparing string
            Dim ObjectCompare As New CaseInsensitiveComparer
            compareResult = ObjectCompare.Compare(x.ToString, y.ToString)
        End If
        Return compareResult
    End Function

End Class

Windows Form Listview ColumnClick

Private prevColumnClick As Integer 'to store previous sorted column number
Private secondary_column_to_sort As Integer = 0 'column 0

Private Sub lvLog_ColumnClick(sender As Object, e As ColumnClickEventArgs) Handles lvLog.ColumnClick
    Dim myListView As ListView = DirectCast(sender, ListView)
    Dim sort_order As System.Windows.Forms.SortOrder

    If myListView.Columns(e.Column).Tag Is Nothing Then
        sort_order = SortOrder.Ascending
    Else
        ' Get previous sort order information from columns .tag
        sort_order = DirectCast(myListView.Columns(e.Column).Tag, System.Windows.Forms.SortOrder)
    End If

    If (prevColumnClick = e.Column) Then
        If sort_order = SortOrder.Ascending Then
            sort_order = SortOrder.Descending
        Else
            sort_order = SortOrder.Ascending
        End If
    End If

    ' Initialize ColumnSorter class
    myListView.ListViewItemSorter = New ListViewColumnSorter(e.Column, sort_order, secondary_column_to_sort)

    ' Perform the sort with these new sort options.
    'myListView.Sort()

    ' Store current column sorting order
    myListView.Columns(e.Column).Tag = sort_order

    ' Store previous column number clicked 
    prevColumnClick = e.Column

End Sub
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This is probably not the most efficient way, but you can simply do the following:

listView.Sort(5);    // Column F, then
listView.Sort(0);    // Column A

Note the reverse order.

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Is it online or winform? On the web, you can compose an expression that has comma separated columns and pass it to the sort () method in the view list

Framework 3.5 and higher though ...

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Well, if you just need to sort the columns, try using List of List; for example like this:

List<List<string>> lstColumns = new List<List<string>>();

Haven't tried it but just thought of a quick solution.

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