Operator is not defined for types of string and system.collections.generic.list(of string)

Hello,
I am trying to run a stored procedure through ADO.NET and I need to pass a list of strings as a single parameter. I have a function that gets me the list of values from the checkbox list control and passes it as comma separated values like 1,2,3 then I split the values in the stored procedure and insert a new row for each value. I ran the stored procedure in SQL like this:
execute RTP.spSaveDetails '65553', '04, 05, 06'
It works fine and inserts 3 new rows however when I try to run it from the code behind I get this error.
operator is not defined for types of string and system.collections.generic.list(of string)
I am not sure how to pass the list received from the function to the stored procedure as a single parameer for example '01,02,03'
Here is the ADO.NET code:
Sub SaveDetails() Dim cn As New SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings("myConn").ConnectionString) ...