請教大家
下列語法為透過參數抓取所要的資料後還回顯示名稱的應用, 要如何讓他可傳回多筆值給同一個 id, 謝謝

dim constring as string="db connection string"
dim ourDataTable As DataTable = nothing
Dim connection as Npgsql.NpgsqlConnection = New Npgsql.NpgsqlConnection(conString)
connection.open()
dim ourAdapter as Npgsql.NpgsqlDataAdapter = New NpgsqlDataAdapter("select .....",connection)
try
 outDatatable = new datatable
 ourAdapter.Fill(ourDataTable)
 for i As integer = 0 to ourDataTable.Rows.Count -1
 if IsDBNull(id) then
 Return ""
 Else
     If ourDataTables.Rows.Count <> 0 then
         Return ourDataTable.Rows(i)("user_name").ToString & "_"
         Else
         Return ""
        End If
        End if
    Next