手工建立DataSet和DataTable 例子

Sub Main()
  Dim ds As New DataSet
  Dim customerTable As DataTable = GetCustomers()
  Dim orderTable As DataTable = GetOrders()

  ds.Tables.Add(customerTable)
  ds.Tables.Add(orderTable)
  ds.Relations.Add("CustomerOrder", _
   New DataColumn() {customerTable.Columns(0)}, _
   New DataColumn() {orderTable.Columns(1)}, True)

  Dim writer As New System.IO.StringWriter
  customerTable.WriteXml(writer, XmlWriteMode.WriteSchema, False)
  PrintOutput(writer, "Customer table, without hierarchy")

  writer = New System.IO.StringWriter
  customerTable.WriteXml(writer, XmlWriteMode.WriteSchema, True)
  PrintOutput(writer, "Customer table, with hierarchy")

  Console.WriteLine("Press any key to continue.")
  Console.ReadKey()
End Sub

Private Function GetOrders() As DataTable
  ' Create sample Customers table, in order
  ' to demonstrate the behavior of the DataTableReader.
  Dim table As New DataTable

  ' Create three columns, OrderID, CustomerID, and OrderDate.
  table.Columns.Add(New DataColumn("OrderID", GetType(System.Int32)))
  table.Columns.Add(New DataColumn("CustomerID", GetType(System.Int32)))
  table.Columns.Add(New DataColumn("OrderDate", GetType(System.DateTime)))

  ' Set the OrderID column as the primary key column.
  table.PrimaryKey = New DataColumn() {table.Columns(0)}

  table.Rows.Add(New Object() {1, 1, #12/2/2003#})
  table.Rows.Add(New Object() {2, 1, #1/3/2004#})
  table.Rows.Add(New Object() {3, 2, #11/13/2004#})
  table.Rows.Add(New Object() {4, 3, #5/16/2004#})
  table.Rows.Add(New Object() {5, 3, #5/22/2004#})
  table.Rows.Add(New Object() {6, 4, #6/15/2004#})
  table.AcceptChanges()
  Return table
End Function

Private Function GetCustomers() As DataTable
  ' Create sample Customers table, in order
  ' to demonstrate the behavior of the DataTableReader.
  Dim table As New DataTable

  ' Create two columns, ID and Name.
  Dim idColumn As DataColumn = table.Columns.Add("ID", _
      GetType(System.Int32))
  table.Columns.Add("Name", GetType(System.String))

  ' Set the ID column as the primary key column.
  table.PrimaryKey = New DataColumn() {idColumn}

  table.Rows.Add(New Object() {1, "Mary"})
  table.Rows.Add(New Object() {2, "Andy"})
  table.Rows.Add(New Object() {3, "Peter"})
  table.Rows.Add(New Object() {4, "Russ"})
  table.AcceptChanges()
  Return table
End Function

Private Sub PrintOutput( _
   ByVal writer As System.IO.TextWriter, ByVal caption As String)

  Console.WriteLine("==============================")
  Console.WriteLine(caption)
  Console.WriteLine("==============================")
  Console.WriteLine(writer.ToString())
End Sub