NPOI Change cell backcolor (セルの背景色変更)

  Private Sub ChangeCellBackColor()
        Dim oldStyle As HSSFCellStyle = Sht.GetRow(rowNum).GetCell(ClmNum).CellStyle
        Dim newStyle = wb.CreateCellStyle

        With newStyle
            .Alignment = oldStyle.Alignment
            .WrapText = oldStyle.WrapText
            .VerticalAlignment = oldStyle.VerticalAlignment
            .SetFont(_srcBook.GetFontAt(oldStyle.FontIndex))

            'New Color
            .FillPattern = FillPatternType.SOLID_FOREGROUND
            .FillForegroundColor = IndexedColors.YELLOW.Index
        End With

        'Set New Style
        Sht.GetRow(rowNum).GetCell(ClmNum).CellStyle = newStyle
    End Sub