stored procedure Select in : How to execute stored procedure by select in instead of = by vb.net and mssql stored procedure

        Dim sSQL As String
        Dim objConn As SqlConnection
        Dim objcmd As SqlCommand
        Dim da As SqlDataAdapter
        Dim ds = New DataSet()

        sSQL = "getinvoice"
        objConn = utility.getconnect
        objcmd = New SqlCommand(sSQL, objConn)
        objcmd.CommandType = CommandType.StoredProcedure
        objcmd.Parameters.Add("@invoiceid", SqlDbType.VarChar)
        objcmd.Parameters.Item("@invoiceid").Value = "1,5,13,18"    '<-- problem
        da = New SqlDataAdapter(objcmd)
        da.Fill(ds)

        ALTER PROCEDURE [dbo].[getinvoices]
        @invoiceid varchar(50)
        AS
        BEGIN
        select * from invoice where invoiceid in @invoiceid     '<-- problem
        END