3 or more case in iif

Hi, how to change this code
Text='<%# IIf(Eval("main1") = "1", "2") %>' to:
If (Eval("main1") = "1") then text="a" End if If (Eval("main1") = "2") then text="b" End if If (Eval("main1") = "3") then text="c" End if ...