ADO.NET :: Generate Statement Dynamically?

I have a sp that generates a result looks like below

Userid orgid

1 100
1 200
1 400
2 100

I would like to generate a string something like below by looping thru the output result data table using ado.netUserid 1 should generate It needs to generate below statement surround by {} and separated by comma(,) if it has multiple orgids.. and orgid( after & ) need to be dynamically assigned in the string based on the table..

{[Org].[org ID].&[100], [Org].[org ID].&[200] ,[Org].[org ID].&[400] }
Userid =2
{[Org].[org ID].&[100] }

How can I dynamically generate this statement? I can generate the stament if there is only one orgid for user but if you have multiple orgs .. not sure how Ic an concatenate multiple orgids by comma..

AllowedSet = "{[Client].[Client ID].&[" + ClientID +
"]}";