Realçar Parte de um texto em uma célula do datagridview

Como destacar parte de um texto em uma célula do datagridview? Eu estou usando c #.
Por exemplo, livro de pesquisas do usuário. uma célula contém um marcador. Quero destacar "livro" no marcador. Obrigado.

Edição. Esse código está ok?

Private Sub DataGridView1_CellPainting(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellPaintingEventArgs) Handles DataGridView1.CellPainting

    If e.RowIndex >= 0 And e.ColumnIndex >= 0 Then

        e.Handled = True
        e.PaintBackground(e.CellBounds, True)

        Dim sw As String = GetSearchWord(e.ColumnIndex)
        If Not String.IsNullOrEmpty(sw) Then

            Dim val As String = DirectCast(e.FormattedValue, String)

            Dim sindx As Integer = val.ToLower.IndexOf(sw.ToLower)
            If sindx >= 0 Then
                'the highlite rectangle
                Dim hl_rect As New Rectangle()
                hl_rect.Y = e.CellBounds.Y + 2
                hl_rect.Height = e.CellBounds.Height - 5

                'find the size of the text before the search word
                'and the size of the search word
                Dim sBefore As String = val.Substring(0, sindx)
                Dim sWord As String = val.Substring(sindx, sw.Length)
                Dim s1 As Size = TextRenderer.MeasureText(e.Graphics, sBefore, e.CellStyle.Font, e.CellBounds.Size)
                Dim s2 As Size = TextRenderer.MeasureText(e.Graphics, sWord, e.CellStyle.Font, e.CellBounds.Size)

                'adjust the widths to make the highlite more accurate
                If s1.Width > 5 Then
                    hl_rect.X = e.CellBounds.X + s1.Width - 5
                    hl_rect.Width = s2.Width - 6
                Else
                    hl_rect.X = e.CellBounds.X + 2
                    hl_rect.Width = s2.Width - 6
                End If

                'use darker highlight when the row is selected
                Dim hl_brush As SolidBrush
                If ((e.State And DataGridViewElementStates.Selected) <> DataGridViewElementStates.None) Then
                    hl_brush = New SolidBrush(Color.DarkGoldenrod)
                Else
                    hl_brush = New SolidBrush(Color.LightGoldenrodYellow)
                End If

                'paint the background behind the search word
                e.Graphics.FillRectangle(hl_brush, hl_rect)

                hl_brush.Dispose()
            End If
        End If

        'paint the content as usual
        e.PaintContent(e.CellBounds)
    End If
End Sub

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