Sorting data in ascending order in a datagridview

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:

Code:

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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)

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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.

You are actually sorting strings, not numbers.

One solution is to add numbers to grid:

Code:

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

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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:

Code:

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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

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And you call it:

Code:

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

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

Teme64 @ Windows Developer Blog

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.

Code:

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DataGridView1.Rows.Add(3)

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

Code:

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DataGridView1.Rows.Add(3)

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

Teme64 @ Windows Developer Blog

vb.net Code:

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

vb.net Code:

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