DataGridView - Sort Multiple Columns

  • Thread starter Thread starter Robert Robinson
  • Start date Start date
R

Robert Robinson

I am using the following code to sort two columns; for example,
lastName, firstName.

Public Class ARowComparer
Implements System.Collections.IComparer
Private sortOrderModifier As Integer = 1

Public Sub New(ByVal sortOrder As SortOrder)
If sortOrder = sortOrder.Descending Then
sortOrderModifier = -1
ElseIf sortOrder = sortOrder.Ascending Then
sortOrderModifier = 1
End If
End Sub

Public Function Compare(ByVal x As Object, ByVal y As Object) As
Integer _
Implements System.Collections.IComparer.Compare

Dim DataGridViewRow1 As DataGridViewRow = CType(x, DataGridViewRow)
Dim DataGridViewRow2 As DataGridViewRow = CType(y, DataGridViewRow)

' Try to sort based on the Last Name column.
Dim CompareResult As Integer = System.String.Compare( _
DataGridViewRow1.Cells(3).Value.ToString(), _
DataGridViewRow2.Cells(3).Value.ToString())

' If the Last Names are equal, sort based on the First Name.
If CompareResult = 0 Then
CompareResult = System.String.Compare( _
DataGridViewRow1.Cells(2).Value.ToString(), _
DataGridViewRow2.Cells(2).Value.ToString())
End If
Return CompareResult * sortOrderModifier
End Function
End Class

The code works fine, but I need to be able to sort a first column in
ascending order and a second in descending order. The present code sorts
both columns in either ascending or descending order.
Does anyone know the best approach for a multiple column sort that has
this capability.
Thank you very much.

Robbie
 
I am using the following code to sort two columns; for example,
lastName, firstName.

Public Class ARowComparer
Implements System.Collections.IComparer
Private sortOrderModifier As Integer = 1

Public Sub New(ByVal sortOrder As SortOrder)
If sortOrder = sortOrder.Descending Then
sortOrderModifier = -1
ElseIf sortOrder = sortOrder.Ascending Then
sortOrderModifier = 1
End If
End Sub

Public Function Compare(ByVal x As Object, ByVal y As Object) As
Integer _
Implements System.Collections.IComparer.Compare

Dim DataGridViewRow1 As DataGridViewRow = CType(x,
DataGridViewRow) Dim DataGridViewRow2 As DataGridViewRow =
CType(y, DataGridViewRow)

' Try to sort based on the Last Name column.
Dim CompareResult As Integer = System.String.Compare( _
DataGridViewRow1.Cells(3).Value.ToString(), _
DataGridViewRow2.Cells(3).Value.ToString())

' If the Last Names are equal, sort based on the First Name.
If CompareResult = 0 Then
CompareResult = System.String.Compare( _
DataGridViewRow1.Cells(2).Value.ToString(), _
DataGridViewRow2.Cells(2).Value.ToString())
End If
Return CompareResult * sortOrderModifier
End Function
End Class

The code works fine, but I need to be able to sort a first column in
ascending order and a second in descending order. The present code
sorts both columns in either ascending or descending order.
Does anyone know the best approach for a multiple column sort that has
this capability.
Thank you very much.

Robbie
Click to expand...

That sounds easy, so maybe I'm missing something. Just reverse the order
of the two arguments to the 2nd Compare call, so you are comparing
DataGridViewRow2... to DataGridRow1... That should do it.

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Dan Cooperstock
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Hi Dan,

That is a great suggestion. I tried it and it works perfectly.
My only problem is having to hang my head in shame for not having
considered the simple exchange of the rows being compared.
Thank you very much.

Robbie
 
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