如何确定和识别Excel中单元格的背景颜色索引？

Function getRGB1(FCell As Range) As String
'UpdatebyExtendoffice20170714
    Dim xColor As String
    xColor = CStr(FCell.Interior.Color)
    xColor = Right("000000" & Hex(xColor), 6)
    getRGB1 = Right(xColor, 2) & Mid(xColor, 3, 2) & Left(xColor, 2)
End Function

Function getRGB2(FCell As Range) As String
   'UpdatebyExtendoffice20170714  
    Dim xColor As Long
    Dim R As Long, G As Long, B As Long
    xColor = FCell.Interior.Color
    R = xColor Mod 256
    G = (xColor \ 256) Mod 256
    B = (xColor \ 65536) Mod 256
    getRGB2 = "R=" & R & ", G=" & G & ", B=" & B
End Function

Function getRGB3(FCell As Range, Optional Opt As Integer = 0) As Long
 'UpdatebyExtendoffice20170714
    Dim xColor As Long
    Dim R As Long, G As Long, B As Long
    xColor = FCell.Interior.Color
    R = xColor Mod 256
    G = (xColor \ 256) Mod 256
    B = (xColor \ 65536) Mod 256
    Select Case Opt
        Case 1
            getRGB3 = R
        Case 2
            getRGB3 = G
        Case 3
            getRGB3 = B
        Case Else
            getRGB3 = xColor
    End Select
End Function