SSRS Code to Alternate Color for columns in Matrix

SSRS_Matrix_Color.vb

    Dim yearGroup = New System.Collections.Hashtable()

    Function GetGroupColor(groupName As String, color1 as string, color2 as string) As String

        If yearGroup.ContainsKey(groupName) Then
            Return yearGroup(groupName)
        End If

        Dim color = IIf(yearGroup.Count() Mod 2 = 0, color1, color2)
        yearGroup.Add(groupName, color)

        Return color
    End Function

'code to use function if the column group is CalendarQuarter - you want to use the ReportItems collection instead of Fields because of NULL values

=Code.GetGroupColor(ReportItems!CalendarQuarter.Value
	,"WhiteSmoke"
	,"White"
)