Sorting a DataTable using LINQ, when sort-by-columns may vary

Question

I need to sort DataTables, however the sort-by-columns vary.

Scenario #1, DataTable1 should be sorted by "Column1".

Scenario #2, DataTable2 should be sorted by "Column1, Column2".

Below is my first attempt at creating a helper function for this purpose. This works ok.

Private Sub SortDataTable(ByRef dataTable As DataTable, ByVal sortColumnNames As List(Of String))
    'Validation (not shown here)

    Dim sortOrder = String.Join(", ", sortColumnNames)

    dataTable.DefaultView.Sort = sortOrder
    dataTable = dataTable.DefaultView.Table
End Sub

I tried implementing this in LINQ, however, I don't know how to pass multiple sort-by-columns to the lambda function. Work-in-progress code shown below.

Private Sub SortDataTable(ByRef dataTable As DataTable, ByVal sortColumnNames As List(Of String))
        'Validation (not shown here)

        dataTable.AsEnumerable().OrderBy(Function (row) row(sortColumnNames(0))).ThenBy(...)
    End Sub

How should I pass multiple sort-by-columns to the OrderBy/ThenBy extension methods?

Artur Udod · Accepted Answer · 2013-05-22 12:45:48Z

3

Something like that:

Private Function SortDataTable(table As DataTable, ParamArray columns As String()) As DataTable
    If columns.Length = 0 Then
        Return table
    End If

    firstColumn = columns.First()

    Dim result = table.AsEnumerable().OrderBy(Function(r) r(firstColumn))

    For Each columnName As var In columns.Skip(1)
        result = result.ThenBy(Function(r) r(columnName))
    Next

    Return result.AsDataView().ToTable()

End Function

Converted from this C# code ( I've written this in C# and then used http://www.developerfusion.com/tools/convert/csharp-to-vb/ ):

DataTable SortDataTable(DataTable table, params string[] columns)
{
    if (columns.Length == 0)
    {
        return table;
    }

    firstColumn = columns.First();

    var result = table.AsEnumerable().OrderBy(r => r[firstColumn]);

    foreach (var columnName in columns.Skip(1))
    {
        result = result.ThenBy(r => r[columnName]);
    }

    return result.AsDataView().ToTable();
}

PS: didn't test that. But that's very simple, so should be no problems.

answered May 22, 2013 at 12:45

Artur Udod

4,8011 gold badge35 silver badges59 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Channs Over a year ago

Damn! I missed storing the LINQ expression into a variable, that's why ThenBy wasn't available. Thanks much.

Collectives™ on Stack Overflow

Sorting a DataTable using LINQ, when sort-by-columns may vary

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related