Sorting data in ascending order in a datagridview

[appolospb]

I am having a few problems getting a column in a datagridview to sort its items correctly in ascending order. The column contains number (File size) data so i simply want it to list the files in smallest to biggest order (Acsending order) but this doesnt work. Below is a example of the code im using for testing:

DataGridView1.Columns.Add("", "Number:")
DataGridView1.Rows.Add("1")
DataGridView1.Rows.Add("2")
DataGridView1.Rows.Add("3")
DataGridView1.Rows.Add("4")
DataGridView1.Rows.Add("51")
DataGridView1.Rows.Add("22")
DataGridView1.Rows.Add("6334")
DataGridView1.Rows.Add("610")

DataGridView1.Sort(DataGridView1.Columns(0), System.ComponentModel.ListSortDirection.Ascending)

You would expect the above code to order the items in '1/2/3/4/22/51/610/6334' order when set to ascending order and reversed when in descending order. What actually happens is the items are displayed as follows:

1/2/22/3/4/51/610/6334

What am i doing wrong?. It appears it only sorts the numbers based on their 1st digit so any double digit or above numbers dont get sorted correctly.

[Teme64]

You are actually sorting strings, not numbers.

One solution is to add numbers to grid:

DataGridView1.Rows.Add(1)
DataGridView1.Rows.Add(2)
DataGridView1.Rows.Add(3)

instead of strings.

The second solution is to provide your own sorting routine that implements ICompare interface. Here's a Q&D version for integers:

Option Explicit On
Option Strict On
Public Class CDataGridViewComparer
  Implements IComparer

  Private m_Col As Integer
  Private m_SortOrder As Integer

  Public Sub New()
    ' Initialize

  End Sub

  Public Sub New(ByVal column As Integer)
    '
    ' Initialize
    m_Col = column

  End Sub

  Public Sub New(ByVal column As Integer, ByVal SortOrder As Integer)
    '
    ' Initialize
    m_Col = column
    m_SortOrder = SortOrder

  End Sub

  Protected Overrides Sub Finalize()
    '
    ' Terminate
    MyBase.Finalize()

  End Sub

  Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer _
    Implements IComparer.Compare
    '
    ' Compare
    '
    Dim TempInt1 As Integer
    Dim TempInt2 As Integer

    Try
      If m_SortOrder = System.ComponentModel.ListSortDirection.Ascending Then
        If Integer.TryParse(CType(x, DataGridViewRow).Cells(m_Col).Value.ToString, TempInt1) AndAlso _
          Integer.TryParse(CType(y, DataGridViewRow).Cells(m_Col).Value.ToString, TempInt2) Then
          If CInt(TempInt1) < CInt(TempInt2) Then
            Return -1
          ElseIf CInt(TempInt1) > CInt(TempInt2) Then
            Return 1
          End If
        End If
      Else
        If Integer.TryParse(CType(x, DataGridViewRow).Cells(m_Col).Value.ToString, TempInt1) AndAlso _
          Integer.TryParse(CType(y, DataGridViewRow).Cells(m_Col).Value.ToString, TempInt2) Then
          If CInt(TempInt1) > CInt(TempInt2) Then
            Return -1
          ElseIf CInt(TempInt1) < CInt(TempInt2) Then
            Return 1
          End If
        End If
      End If
      Return 0
    Catch ex As Exception
      ' Handle exception
    End Try

  End Function

End Class

And you call it:

DataGridView1.Sort(New CDataGridViewComparer(0, System.ComponentModel.ListSortDirection.Ascending))

If you need to, you can extend Compare function to handle dates etc.

Teme64 @ Windows Developer Blog

[appolospb]

Thanks for your help. As the job is just a little enhancement to my program i wanted to stick with a very simple solution to the problem. I have tried the below code and it appears the .add row command only works with strings. If you use the below code nothing appears in the datagridview. Its possible i am executing the command incorrectly but i cant find any other method on MSDN.

DataGridView1.Rows.Add(3)

Ill give method 2 a go if i cant find a soloution to the above problem. Thank you for your assistance

[Teme64]

DataGridView1.Rows.Add(3)

actually adds three new rows, not an integer with value three. Sorry, my mistake The second solution should be fine.

Teme64 @ Windows Developer Blog

[jmcilhinney]

DataGridView1.Rows(DataGridView1.Rows.Add()).Cells(0).Value = someInteger

DataGridView1.Rows.Add(New Object() {someInteger})