How to filter the search based on the typed text in WinForms GridGroupingControl?

this.textBoxExt1.TextChanged += new EventHandler(textBoxExt1_TextChanged);
this.gridGroupingControl1.QueryCellStyleInfo += new GridTableCellStyleInfoEventHandler(gridGroupingControl1_QueryCellStyleInfo);
void gridGroupingControl1_QueryCellStyleInfo(object sender, GridTableCellStyleInfoEventArgs e)
{
    //Highlight the searching text.
    if (search)
    {
        if (e.Style.Text.Contains(this.textBoxExt1.Text) && e.TableCellIdentity.DisplayElement.Kind == DisplayElementKind.Record)
            e.Style.BackColor = Color.Orange;
    }
}
bool search = false;
RecordFilterDescriptor recordFilter = new RecordFilterDescriptor();
void textBoxExt1_TextChanged(object sender, EventArgs e)
{
    //Check whether the text is present or not.
    if (!string.IsNullOrEmpty(this.textBoxExt1.Text))
    {                
        recordFilter.Expression = "[CustomerName] Match " + "'" + this.textBoxExt1.Text + "'";
        this.gridGroupingControl1.TableDescriptor.RecordFilters.Add(recordFilter);
        search = true;
    }
    else
    {
        this.gridGroupingControl1.TableDescriptor.RecordFilters.Clear();
        search = false;
    }
            
}

Private Me.textBoxExt1.TextChanged += New EventHandler(AddressOf textBoxExt1_TextChanged)
Private Me.gridGroupingControl1.QueryCellStyleInfo += New GridTableCellStyleInfoEventHandler(AddressOf gridGroupingControl1_QueryCellStyleInfo)
Private Sub gridGroupingControl1_QueryCellStyleInfo(ByVal sender As Object, ByVal e As GridTableCellStyleInfoEventArgs)
  'Highlight the searching text.
  If search Then
    If e.Style.Text.Contains(Me.textBoxExt1.Text) AndAlso e.TableCellIdentity.DisplayElement.Kind Is DisplayElementKind.Record Then
      e.Style.BackColor = Color.Orange
    End If
  End If
End Sub
Private search As Boolean = False
Private recordFilter As New RecordFilterDescriptor()
Private Sub textBoxExt1_TextChanged(ByVal sender As Object, ByVal e As EventArgs)
  'Check whether the text is present or not.
  If Not String.IsNullOrEmpty(Me.textBoxExt1.Text) Then
    recordFilter.Expression = "[CustomerName] Match " & "'" & Me.textBoxExt1.Text & "'"
    Me.gridGroupingControl1.TableDescriptor.RecordFilters.Add(recordFilter)
      search = True
  Else
    Me.gridGroupingControl1.TableDescriptor.RecordFilters.Clear()
      search = False
  End If
End Sub