DataTableReader.NextResult DataTableReader.NextResult DataTableReader.NextResult DataTableReader.NextResult Method

定義

DataTableReader を次の結果に進めます (存在する場合)。Advances the DataTableReader to the next result set, if any.

public:
 override bool NextResult();
public override bool NextResult ();
override this.NextResult : unit -> bool
Public Overrides Function NextResult () As Boolean

戻り値

別の結果セットがあった場合は true。それ以外の場合は falsetrue if there was another result set; otherwise false.

例外

閉じられた DataTableReader 内を移動しようとしました。An attempt was made to navigate within a closed DataTableReader.

次の例では、testconstructor メソッドによっDataTableて2つのインスタンスが作成されます。In the following example, the TestConstructor method creates two DataTable instances. DataTableReaderクラスのこのコンストラクターを示すために、このサンプルでは、2 DataTableReaderDataTablesのを含む配列に基づいて新しいを作成し、単純な操作を実行します。最初のいくつかの列からの内容をコンソールに出力します。windows.In order to demonstrate this constructor for the DataTableReader class, the sample creates a new DataTableReader based on an array that contains the two DataTables, and performs a simple operation, printing the contents from the first few columns to the console window. このアプリケーションをテストするには、新しいコンソールアプリケーションを作成し、新しく作成したファイルにサンプルコードを貼り付けます。In order to test this application, create a new Console application, and paste the sample code into the newly created file.

private static void TestConstructor()
{
    // Create two data adapters, one for each of the two
    // DataTables to be filled.
    DataTable customerDataTable = GetCustomers();
    DataTable productDataTable = GetProducts();

    // Create the new DataTableReader.
    using (DataTableReader reader = new DataTableReader(
               new DataTable[] { customerDataTable, productDataTable }))
    {
        // Print the contents of each of the result sets.
        do
        {
            PrintColumns(reader);
        } while (reader.NextResult());
    }

    Console.WriteLine("Press Enter to finish.");
    Console.ReadLine();
}

private static DataTable GetCustomers()
{
    // Create sample Customers table, in order
    // to demonstrate the behavior of the DataTableReader.
    DataTable table = new DataTable();
  
    // Create two columns, ID and Name.
    DataColumn idColumn = table.Columns.Add("ID", typeof(int));
    table.Columns.Add("Name", typeof(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" });
    return table;
}

private static DataTable GetProducts()
{
    // Create sample Products table, in order
    // to demonstrate the behavior of the DataTableReader.
    DataTable table = new DataTable();
  
    // Create two columns, ID and Name.
    DataColumn idColumn = table.Columns.Add("ID", typeof(int));
    table.Columns.Add("Name", typeof(string ));
  
    // Set the ID column as the primary key column.
    table.PrimaryKey = new DataColumn[] { idColumn };

    table.Rows.Add(new object[] { 1, "Wireless Network Card" });
    table.Rows.Add(new object[] { 2, "Hard Drive" });
    table.Rows.Add(new object[] { 3, "Monitor" });
    table.Rows.Add(new object[] { 4, "CPU" });
    return table;
}

private static void PrintColumns(DataTableReader reader)
{
    // Loop through all the rows in the DataTableReader
    while (reader.Read())
    {
        for (int i = 0; i < reader.FieldCount; i++)
        {
            Console.Write(reader[i] + " ");
        }
        Console.WriteLine();
    }
}
Private Sub TestConstructor()
   ' Create two data adapters, one for each of the two
   ' DataTables to be filled.
   Dim customerDataTable As DataTable = GetCustomers()
   Dim productDataTable As DataTable = GetProducts()

   ' Create the new DataTableReader.
   Using reader As New DataTableReader( _
      New DataTable() {customerDataTable, productDataTable})

      ' Print the contents of each of the result sets.
      Do
         PrintColumns(reader)
      Loop While reader.NextResult()
   End Using

   Console.WriteLine("Press Enter to finish.")
   Console.ReadLine()

End Sub

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(Integer))
   table.Columns.Add("Name", GetType(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"})
   Return table
End Function

Private Function GetProducts() As DataTable
   ' Create sample Products 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(Integer))
   table.Columns.Add("Name", GetType(String))

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

   table.Rows.Add(New Object() {1, "Wireless Network Card"})
   table.Rows.Add(New Object() {2, "Hard Drive"})
   table.Rows.Add(New Object() {3, "Monitor"})
   table.Rows.Add(New Object() {4, "CPU"})
   Return table
End Function

Private Sub PrintColumns( _
   ByVal reader As DataTableReader)

   ' Loop through all the rows in the DataTableReader.
   Do While reader.Read()
      For i As Integer = 0 To reader.FieldCount - 1
         Console.Write(reader(i).ToString() & " ")
      Next
      Console.WriteLine()
   Loop
End Sub

コンソールウィンドウには、次の結果が表示されます。The Console window displays the following results:

1 Mary  
2 Andy  
3 Peter  
4 Russ  
1 Wireless Network Card  
2 Hard Drive  
3 Monitor  
4 CPU  

注釈

複数のテーブルを含むを作成するか、2つDataTableReader DataTable以上のDataSetインスタンスを含む配列を作成することによって生成される複数の結果を処理するために使用されます。Used to process multiple results that can be generated by creating a DataTableReader over a DataSet that contains two or more tables, or an array that contains two or more DataTable instances.

最初のDataTableReader結果に新しいが配置されます。A new DataTableReader is positioned on the first result.

適用対象