how to increase numeric value present in the string in vb.net : i m  using this query in  vb.net
 
Raw_data = Alltext_line.Substring(Alltext_line.IndexOf("R|1"))

and i want to increase R|1 to R|2,R|3 and so on using for loop

i tried it many ways but getting error "string to double is invalid"

any help will be appreciated 
