Private Function Find()
  Dim items As NodeCollection = gridKorisnici.Rows.Items
  Dim item As NodeBase
  Try
    For Each item In items
      If item.Item(1).ToString.ToLower.IndexOf(txtFind.Text.ToString.ToLower)  -1 Then
        gridKorisnici.Focus()
        gridKorisnici.Selected = item
        Exit Function
      End If
    Next
  Catch e as Exception
    System.Diagnostics.Debug.WriteLine("Exception: " + e.Message)
    System.Diagnostics.Debug.WriteLine("Stack Trace: " + e.StackTrace)
  End Try
End Function

Dim data As Object()
            data = New Object() {objKorisnik.Ime, objKorisnik.Prezime, objKorisnik.Odjel, objKorisnik.Ured, objKorisnik.Limit, objKorisnik.Point, objKorisnik.Mobitel, objKorisnik.ID}
            Dim n As NodeBase = AddNestedTo(gridKorisnici.Rows.Items, data)
            AddItemsTo(n.Items, objKorisnik.ID)

Private Sub AddItemsTo(ByVal nodes As NodeCollection, ByVal id As Long)
        Dim veza As New Veza
        Dim objVeze As VezaCollection = veza.GetInfo(id)
        Dim objVeza As Veza
        For Each objVeza In objVeze
            If objVeza.Broj  0 Then
                Dim data As Object()
                data = New Object() {Format(CInt(objVeza.Broj), "0000000000"), Format(objVeza.Aktivirano, "dd.MM.yyyy"), IIf(objVeza.Suspendirano.Year = 1, String.Empty, Format(objVeza.Suspendirano, "dd.MM.yyyy")), objVeza.VezaID}
                nodes.Add(New Node(Data))
            End If
            If Not objVeze Is Nothing Then objVeze = Nothing
        Next
    End Sub

Private Function AddNestedTo(ByVal nodes As NodeCollection, ByVal obj As Object) As NodeBase
        Dim nested As NodeBase = New NestedGridNode
        nested.Value = obj
        nodes.Add(nested)
        Return nested
    End Function

Private Sub gridKorisnici_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles gridKorisnici.KeyDown
        If e.KeyCode = Keys.F5 Then LoadKorisnici()
        If e.KeyCode = Keys.Enter Then IzmjeniKorisnika()
        If e.KeyCode = Keys.Delete Then btnObrisi_Click(Nothing, Nothing)
        If e.Control = True And e.KeyCode = Keys.A Then gridKorisnici.Rows.SelectAll()
              If e.KeyCode = Keys.F Then
            txtFind.Focus()
            txtFind.SelectAll()          
        End If
    End Sub

[VB.Net]
    Public Class SearchData
      Public FoundCol As Integer
      Public FoundNode As NodeBase
      Public ReadOnly SearchText As String
      Public Sub New(ByVal searchString As String)
        Me.SearchText = searchString
      End Sub
    End Class

    Private Function Find(ByVal nodes As NodeCollection, ByVal data As SearchData) As Boolean
      If (Not nodes Is Nothing) Then
        For Each child As NodeBase In nodes
          Dim val As Object() = child.Value
          If (Not val Is Nothing) Then
            For i As Integer = 0 To val.Length - 1
              Dim cellValue As String = val.GetValue(i)
              If (Not cellValue Is Nothing And cellValue.Equals(data.SearchText)) Then
                data.FoundNode = child
                data.FoundCol = i
                Return True
              End If
            Next
          End If
          If (child.HasChildren) Then
            If Find(child.Items, data) Then
              Return True
            End If
          End If
        Next
      End If
      Return False
    End Function

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
      Dim data As SearchData = New SearchData("Some text for search")
      If (Find(nestedGrid.Rows.Items, data)) Then
        nestedGrid.Selected = data.FoundNode
      End If
    End Sub