DataSet.CreateDataReader Metoda

Definicja

Zwraca DataTableReader z jednym zestawem wyników na DataTable, w tej samej kolejności, w której tabele są wyświetlane w kolekcji Tables.Returns a DataTableReader with one result set per DataTable, in the same sequence as the tables appear in the Tables collection.

Przeciążenia

CreateDataReader(DataTable[])

Zwraca DataTableReader z jednym zestawem wyników na DataTable.Returns a DataTableReader with one result set per DataTable.

CreateDataReader()

Zwraca DataTableReader z jednym zestawem wyników na DataTable, w tej samej kolejności, w której tabele są wyświetlane w kolekcji Tables.Returns a DataTableReader with one result set per DataTable, in the same sequence as the tables appear in the Tables collection.

Przykłady

W tym przykładzie Aplikacja konsolowa tworzy trzy wystąpienia DataTable i dodaje je do DataSet.This example, a Console application, creates three DataTable instances and adds each to a DataSet. Przykład wywołuje metodę CreateDataReader i wyświetla zawartość zwróconego DataTableReader.The example calls the CreateDataReader method and displays the contents of the returned DataTableReader. Należy zauważyć, że kolejność zestawów wyników w DataTableReader jest kontrolowana przez kolejność DataTable wystąpień przesłanych jako parametry.Note that the order of the result sets in the DataTableReader is controlled by the order of the DataTable instances passed as parameters.

Uwaga

Ten przykład pokazuje, jak używać jednej ze przeciążonych wersji CreateDataReader.This example shows how to use one of the overloaded versions of CreateDataReader. Inne przykłady, które mogą być dostępne, można znaleźć w tematach dotyczących poszczególnych przeciążeń.For other examples that might be available, see the individual overload topics.

static DataTable customerTable;
static DataTable productTable;
static DataTable emptyTable;

static void Main()
{
    DataSet dataSet = new DataSet();

    // Add some DataTables to the DataSet, including
    // an empty DataTable:
    emptyTable = new DataTable();
    productTable = GetProducts();
    customerTable = GetCustomers();

    dataSet.Tables.Add(customerTable);
    dataSet.Tables.Add(emptyTable);
    dataSet.Tables.Add(productTable);
    TestCreateDataReader(dataSet);

    Console.WriteLine("Press any key to continue.");
    Console.ReadKey();
}

private static void TestCreateDataReader(DataSet dataSet)
{
    // Given a DataSet, retrieve a DataTableReader
    // allowing access to all the DataSet's data.
    // Even though the dataset contains three DataTables,
    // this code will only display the contents of two of them,
    // because the code has limited the results to the 
    // DataTables stored in the tables array. Because this
    // parameter is declared using the ParamArray keyword, 
    // you could also include a list of DataTable instances 
    // individually, as opposed to supplying an array of 
    // DataTables, as in this example:
    using (DataTableReader reader = 
        dataSet.CreateDataReader(productTable, emptyTable))
    {
        do
        {
            if (!reader.HasRows)
            {
                Console.WriteLine("Empty DataTableReader");
            }
            else
            {
                PrintColumns(reader);
            }
            Console.WriteLine("========================");
        } while (reader.NextResult());
    }
}

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" });
    table.AcceptChanges();
    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" });
    table.AcceptChanges();
    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 emptyTable As DataTable
Private customerTable As DataTable
Private productTable As DataTable

Sub Main()
  Dim dataSet As New DataSet
  ' Add some DataTables to the DataSet, including
  ' an empty DataTable:

  emptyTable = New DataTable()
  productTable = GetProducts()
  customerTable = GetCustomers()

  dataSet.Tables.Add(customerTable)
  dataSet.Tables.Add(emptyTable)
  dataSet.Tables.Add(productTable)
  TestCreateDataReader(dataSet)

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

Private Sub TestCreateDataReader(ByVal dataSet As DataSet)
  ' Given a DataSet, retrieve a DataTableReader
  ' allowing access to all the DataSet's data.
  ' Even though the dataset contains three DataTables,
  ' this code will only display the contents of two of them,
  ' because the code has limited the results to the 
  ' DataTables stored in the tables array. Because this
  ' parameter is declared using the ParamArray keyword, 
  ' you could also include a list of DataTable instances 
  ' individually, as opposed to supplying an array of 
  ' DataTables, as in this example:
  Using reader As DataTableReader = _
      dataSet.CreateDataReader(productTable, emptyTable)
    Do
      If Not reader.HasRows Then
        Console.WriteLine("Empty DataTableReader")
      Else
        PrintColumns(reader)
      End If
      Console.WriteLine("========================")
    Loop While reader.NextResult()
  End Using
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"})
  table.AcceptChanges()
  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"})
  table.AcceptChanges()
  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

W przykładzie przedstawiono następujący kod w oknie konsoli:The example displays the following code in the Console window:

Uwagi

W celu zapewnienia kolejności zestawów wyników w zwróconym DataTableReader, jeśli DataTable w DataSet jest pusta, będzie reprezentowana przez pusty zestaw wyników w ramach zwróconego DataTableReader.In order to ensure the order of the result sets within the returned DataTableReader, if a DataTable within the DataSet is empty, it will be represented by an empty result set within the returned DataTableReader.

CreateDataReader(DataTable[])

Zwraca DataTableReader z jednym zestawem wyników na DataTable.Returns a DataTableReader with one result set per DataTable.

public:
 System::Data::DataTableReader ^ CreateDataReader(... cli::array <System::Data::DataTable ^> ^ dataTables);
public System.Data.DataTableReader CreateDataReader (params System.Data.DataTable[] dataTables);
member this.CreateDataReader : System.Data.DataTable[] -> System.Data.DataTableReader
Public Function CreateDataReader (ParamArray dataTables As DataTable()) As DataTableReader

Parametry

dataTables
DataTable[]

Tablica tabeli danych dostarczająca kolejność zestawów wyników do zwrócenia w DataTableReader.An array of DataTables providing the order of the result sets to be returned in the DataTableReader.

Zwraca

DataTableReader zawierający co najmniej jeden zestaw wyników odpowiadający wystąpieniu DataTable zawartym w DataSetźródłowym.A DataTableReader containing one or more result sets, corresponding to the DataTable instances contained within the source DataSet. Zwracane zestawy wyników są w kolejności określonej przez parametr dataTables.The returned result sets are in the order specified by the dataTables parameter.

Przykłady

W tym przykładzie Aplikacja konsolowa tworzy trzy wystąpienia DataTable i dodaje je do DataSet.This example, a Console application, creates three DataTable instances and adds each to a DataSet. Przykład wywołuje metodę CreateDataReader i wyświetla zawartość zwróconego DataTableReader.The example calls the CreateDataReader method and displays the contents of the returned DataTableReader. Należy zauważyć, że kolejność zestawów wyników w DataTableReader jest kontrolowana przez kolejność DataTable wystąpień przesłanych jako parametry.Note that the order of the result sets in the DataTableReader is controlled by the order of the DataTable instances passed as parameters. Przykład wyświetla wyniki w oknie konsoli.The example displays the results in the Console window.

static DataTable customerTable;
static DataTable productTable;
static DataTable emptyTable;

static void Main()
{
    DataSet dataSet = new DataSet();

    // Add some DataTables to the DataSet, including
    // an empty DataTable:
    emptyTable = new DataTable();
    productTable = GetProducts();
    customerTable = GetCustomers();

    dataSet.Tables.Add(customerTable);
    dataSet.Tables.Add(emptyTable);
    dataSet.Tables.Add(productTable);
    TestCreateDataReader(dataSet);

    Console.WriteLine("Press any key to continue.");
    Console.ReadKey();
}

private static void TestCreateDataReader(DataSet dataSet)
{
    // Given a DataSet, retrieve a DataTableReader
    // allowing access to all the DataSet's data.
    // Even though the dataset contains three DataTables,
    // this code will only display the contents of two of them,
    // because the code has limited the results to the 
    // DataTables stored in the tables array. Because this
    // parameter is declared using the ParamArray keyword, 
    // you could also include a list of DataTable instances 
    // individually, as opposed to supplying an array of 
    // DataTables, as in this example:
    using (DataTableReader reader = 
       dataSet.CreateDataReader(productTable, emptyTable))
    {
        do
        {
            if (!reader.HasRows)
            {
                Console.WriteLine("Empty DataTableReader");
            }
            else
            {
                PrintColumns(reader);
            }
            Console.WriteLine("========================");
        } while (reader.NextResult());
    }
}

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 emptyTable As DataTable
Private customerTable As DataTable
Private productTable As DataTable

Sub Main()
  Dim dataSet As New DataSet
  ' Add some DataTables to the DataSet, including
  ' an empty DataTable:

  emptyTable = New DataTable()
  productTable = GetProducts()
  customerTable = GetCustomers()

  dataSet.Tables.Add(customerTable)
  dataSet.Tables.Add(emptyTable)
  dataSet.Tables.Add(productTable)
  TestCreateDataReader(dataSet)

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

Private Sub TestCreateDataReader(ByVal dataSet As DataSet)
  ' Given a DataSet, retrieve a DataTableReader
  ' allowing access to all the DataSet's data.
  ' Even though the dataset contains three DataTables,
  ' this code will only display the contents of two of them,
  ' because the code has limited the results to the 
  ' DataTables stored in the tables array. Because this
  ' parameter is declared using the ParamArray keyword, 
  ' you could also include a list of DataTable instances 
  ' individually, as opposed to supplying an array of 
  ' DataTables, as in this example:
  Using reader As DataTableReader = _
    dataSet.CreateDataReader(productTable, emptyTable)
    Do
      If Not reader.HasRows Then
        Console.WriteLine("Empty DataTableReader")
      Else
        PrintColumns(reader)
      End If
      Console.WriteLine("========================")
    Loop While reader.NextResult()
  End Using
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

Uwagi

W celu zapewnienia, że kolejność zestawów wyników w zwracanych DataTableReader, jeśli DataTable w DataSet jest pusta, jest reprezentowana przez pusty zestaw wyników w ramach zwróconego DataTableReader.In order to ensure that the order of the result sets within the returned DataTableReader, if a DataTable within the DataSet is empty, it is represented by an empty result set within the returned DataTableReader. Ponieważ ta przeciążona wersja umożliwia podawanie listy DataTable wystąpień jako parametrów, można określić kolejność, w jakiej zestawy wyników pojawiają się w ramach zwróconego DataTableReader.Because this overloaded version allows you to supply a list of DataTable instances as parameters, you can specify the order in which the result sets appear within the returned DataTableReader.

Zobacz też

CreateDataReader()

Zwraca DataTableReader z jednym zestawem wyników na DataTable, w tej samej kolejności, w której tabele są wyświetlane w kolekcji Tables.Returns a DataTableReader with one result set per DataTable, in the same sequence as the tables appear in the Tables collection.

public:
 System::Data::DataTableReader ^ CreateDataReader();
public System.Data.DataTableReader CreateDataReader ();
member this.CreateDataReader : unit -> System.Data.DataTableReader
Public Function CreateDataReader () As DataTableReader

Zwraca

DataTableReader zawierający co najmniej jeden zestaw wyników odpowiadający wystąpieniu DataTable zawartym w DataSetźródłowym.A DataTableReader containing one or more result sets, corresponding to the DataTable instances contained within the source DataSet.

Przykłady

Poniższy przykład tworzy trzy wystąpienia DataTable i dodaje każdy do DataSet.The following example creates three DataTable instances, and adds each to a DataSet. Następnie przykład przekazuje wypełniony DataSet do procedury, która wywołuje metodę CreateDataReader i przechodzi do iteracji przez wszystkie zestawy wyników zawarte w DataTableReader.The example then passes the filled DataSet to a procedure that calls the CreateDataReader method, and proceeds to iterate through all the result sets contained within the DataTableReader. Przykład wyświetla wyniki w oknie konsoli.The example displays the results in the Console window.

static void Main()
{
    DataSet dataSet = new DataSet();
    // Add some DataTables to the DataSet, including
    // an empty DataTable:
    dataSet.Tables.Add(GetCustomers());
    dataSet.Tables.Add(new DataTable());
    dataSet.Tables.Add(GetProducts());
    TestCreateDataReader(dataSet);

    Console.WriteLine("Press any key to continue.");
    Console.ReadKey();
}

private static void TestCreateDataReader(DataSet dataSet)
{
    // Given a DataSet, retrieve a DataTableReader
    // allowing access to all the DataSet's data:
    using (DataTableReader reader = dataSet.CreateDataReader())
    {
        do
        {
            if (!reader.HasRows)
            {
                Console.WriteLine("Empty DataTableReader");
            }
            else
            {
                PrintColumns(reader);
            }
            Console.WriteLine("========================");
        } while (reader.NextResult());
    }
}

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();
    }
}
Sub Main()
  Dim dataSet As New DataSet
  ' Add some DataTables to the DataSet, including
  ' an empty DataTable:
  dataSet.Tables.Add(GetCustomers())
  dataSet.Tables.Add(New DataTable())
  dataSet.Tables.Add(GetProducts())
  TestCreateDataReader(dataSet)

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

Private Sub TestCreateDataReader(ByVal dataSet As DataSet)
  ' Given a DataSet, retrieve a DataTableReader
  ' allowing access to all the DataSet's data:
  Using reader As DataTableReader = dataSet.CreateDataReader()
    Do
      If Not reader.HasRows Then
        Console.WriteLine("Empty DataTableReader")
      Else
        PrintColumns(reader)
      End If
      Console.WriteLine("========================")
    Loop While reader.NextResult()
  End Using
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

Uwagi

W celu zapewnienia kolejności zestawów wyników w zwracanej DataTableReader, jeśli DataTable w DataSet jest pusta, jest reprezentowana przez pusty zestaw wyników w ramach zwróconego DataTableReader.In order to ensure the order of the result sets within the returned DataTableReader, if a DataTable within the DataSet is empty, it is represented by an empty result set within the returned DataTableReader.

Zobacz też

Dotyczy