Public Class MyDataGrid
    Inherits DataGrid

...

  Private Sub DataGrid_Resize(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Resize
         AutoArrange()

    End Sub



Private Sub AutoArrange()
        If Me.TableStyles.Count =  0  _
        Or DataSource Is Nothing Then Exit Sub
        Dim ts As DataGridTableStyle = Me.TableStyles( 0 )
        Dim colStyles As ArrayList = Me.GetVisibleColumns 'получение массива видимых колонок
        Dim ub% = colStyles.Count -  1 
        If ub = - 1  Then Exit Sub
         Dim colStyle As DataGridColumnStyle


        Dim delta% =  0 
        Select Case Me.BorderStyle
            Case BorderStyle.Fixed3D
                delta += SystemInformation.Border3DSize.Width *  2 
            Case BorderStyle.FixedSingle
                delta += SystemInformation.BorderSize.Width *  2 
        End Select
        If ts.RowHeadersVisible Then
            delta += ts.RowHeaderWidth +  2 
        End If
        delta += ub

        Dim w% = Me.Width - delta
        Dim totalWidth%
        Try
            Me.SuspendLayout()
            For i As Int32 =  0  To ub
                colStyle = colStyles(i)
                totalWidth += colStyle.Width
            Next

            For i As Int32 =  0  To ub
                colStyle = colStyles(i)
                colStyle.Width = colStyle.Width / (totalWidth) * w  '* colStyle.Width
            Next
        Finally
            Me.ResumeLayout()
        End Try


    End Sub

    'создание массива видимых колонок
    Private Function GetVisibleColumns() As ArrayList
        Dim ret As New ArrayList
        Dim ts As DataGridTableStyle = Me.TableStyles( 0 )

        Dim dt As DataTable = Me.DataSource
        Dim ub% = ts.GridColumnStyles.Count -  1 
        For i As Int32 =  0  To ub
            If dt.Columns.Contains(ts.GridColumnStyles(i).MappingName) Then
                If ts.GridColumnStyles(i).Width <>  0  Then ret.Add(ts.GridColumnStyles(i))
            End If

               Next
        Return ret
    End Function
end Class