Public Class ColorDataGridTextBoxColumn
    Inherits DataGridTextBoxColumn
    Dim num As Integer
    Dim obj As Object
    Protected Overloads Overrides Sub Paint(ByVal g As Graphics, ByVal bounds _
      As Rectangle, ByVal source As CurrencyManager, ByVal rowNum As Integer, _
      ByVal backBrush As Brush, ByVal foreBrush As Brush, ByVal alignToRight As _
      Boolean)
        obj = Me.GetColumnValueAtRow(source, rowNum)
        If Not obj Is Nothing Then
            If IsNumeric(CType(obj, String).Substring(0, 1)) Then
                num = CType(obj, String).Substring(0, 1)
                If (num > 1 AndAlso num < 10) Then
                    backBrush = New SolidBrush(Color.Blue)
                    foreBrush = New SolidBrush(Color.White)
                    MyBase.TextBox.BackColor = Color.Blue
                End If
            End If
        End If
        MyBase.Paint(g, bounds, source, rowNum, backBrush, foreBrush, _
          alignToRight)
    End Sub
End Class

   Dim dt As New DataTable("Users")
        Dim rnd As New Random(Now.Second)
        Dim ts As New DataGridTableStyle
        Dim dgs As ColorDataGridTextBoxColumn
        Dim r As DataRow
        dt.Columns.Add("ID".ToUpper)
        dt.Columns.Add("Vorname".ToUpper)
        dt.Columns.Add("Nachname".ToUpper)
        For a As Integer = 0 To 10 ' // mit Pseudo-Daten füllen
            r = dt.NewRow
            For b As Integer = 0 To dt.Columns.Count - 2
                r(b) = New String(Chr(rnd.Next(50, 60)), 10)
            Next
            dt.Rows.Add(r)
        Next
        ts.MappingName = "Users"
        For a As Integer = 0 To dt.Columns.Count - 2
            dgs = New ColorDataGridTextBoxColumn
            dgs.MappingName = dt.Columns(a).ColumnName
            dgs.Width = 100
            dgs.HeaderText = dt.Columns(a).ColumnName
            ts.GridColumnStyles.Add(dgs)
        Next
        Me.DataGrid1.TableStyles.Add(ts)
        Me.DataGrid1.DataSource = dt