changing bar fill colours in ssrs chart - reporting-services

Question

SO Post
Current I've got 5 bars in my RS chart - in the future there might be 7 bars or 17 bars or 27 bars!
With a couple of bars I can have an expression like this:
=iif(Fields!Market.Value = "Spain"
,"Gold"
,iif (Fields!Market.Value = "Denmark"
, "Gray"
, iif(Fields!Market.Value = "Italy"
, "Blue"
, "Purple"
)
)
)
If I can't predict how many countries will be included + I'd rather not have to hard code in "Green", "Red" etc how do I change the expression?
I've tried this but it is erroring:
=Switch(Mod(Fields!Rank.Value/CDbl(2))=CDbl(0), "Gold",
Mod(Fields!Rank.Value/CDbl(3))=CDbl(0), "Gray",
Mod(Fields!Rank.Value/CDbl(2))>CDbl(0) "Blue")
Above is the totally incorrect syntax: This works:
=Switch(CDbl(Fields!Rank.Value Mod 2)=CDbl(0), "Gold",
CDbl(Fields!Rank.Value Mod 3)=CDbl(0), "Gray",
CDbl(Fields!Rank.Value Mod 2)>CDbl(0), "Blue")
Ok - the above runs (not sure how!) but the below is based on help from Dominic Goulet and is really easy to follow and nice and expandable to more colours; this is the solution for 5 colours:
=Switch(CDbl(Fields!Rank.Value Mod 5)=CDbl(0), "Gold",
CDbl(Fields!Rank.Value Mod 5)=CDbl(1), "Gray",
CDbl(Fields!Rank.Value Mod 5)=CDbl(2), "Green",
CDbl(Fields!Rank.Value Mod 5)=CDbl(3), "Red",
CDbl(Fields!Rank.Value Mod 5)=CDbl(4), "Pink")

Answer 1

First of all, instead of using many "IIF"s, you should use "Switch", it's leaner that way.
Switch(Fields!Market.Value = "Spain", "Gold",
Fields!Market.Value = "Denmark", "Gray",
Fields!Market.Value = "Italy", "Blue")
Now if you want a color per coutry, you should defenitely store that in your database and pull it out when you need it. That way, a country will always have the same color on every report you have.

Answer 2

It would be better to create a function. For that, go to Report Properties, choose code and type this example :
Public Function Color(ByVal Index as Integer) as String
Select Case Index
Case = 1
return "#a6cee3"
Case = 2
return "#1f78b4"
Case = 3
return "#b2df8a"
Case = 4
return "#33a02c"
Case = 5
return "#fb9a99"
Case = 6
return "#e31a1c"
Case = 7
return "#fdbf6f"
Case = 8
return "#ff7f00"
Case = 9
return "#cab2d6"
Case = 10
return "#6a3d9a"
End Select
End Function
On the Fill option from "Series Properties->Pick color-> Color choose fx
put this code
=Code.Color(rownumber(nothing))
Each bar will have a color.
For the HEX colors I took from the website : http://colorbrewer2.org/#type=qualitative&scheme=Paired&n=10
It shows the best colors that match with each other, so you don't need to think of that. And you can add as many colors as you want