DataTable.CreateDataReader Yöntem

Tanım

Ad Alanı:

System.Data

Bütünleştirilmiş Kod:

System.Data.Common.dll

Kaynak:

DataTable.cs

Bu DataTableiçindeki verilere karşılık gelen bir DataTableReader döndürür.

public:
 System::Data::DataTableReader ^ CreateDataReader();

public System.Data.DataTableReader CreateDataReader ();

member this.CreateDataReader : unit -> System.Data.DataTableReader

Public Function CreateDataReader () As DataTableReader

Döndürülenler

DataTableReader

DataTableReader Kaynak DataTable örneğe karşılık gelen bir sonuç kümesi içeren.

Örnekler

Aşağıdaki konsol uygulaması bir DataTable örnek oluşturur. Örnek daha sonra doldurulan DataTable yöntemini çağıran CreateDataReader ve içindeki sonuçlarda yinelenen bir yordama DataTableReadergeçirir.

static void Main()
{
    TestCreateDataReader(GetCustomers());
    Console.WriteLine("Press any key to continue.");
    Console.ReadKey();
}

private static void TestCreateDataReader(DataTable dt)
{
    // Given a DataTable, retrieve a DataTableReader
    // allowing access to all the tables' data:
    using (DataTableReader reader = dt.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 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()
  TestCreateDataReader(GetCustomers())
  Console.WriteLine("Press any key to continue.")
  Console.ReadKey()
End Sub

Private Sub TestCreateDataReader(ByVal dt As DataTable)
  ' Given a DataTable, retrieve a DataTableReader
  ' allowing access to all the tables's data:
  Using reader As DataTableReader = dt.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 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

Örnek, konsol penceresinde aşağıdaki çıktıyı görüntüler:

1 Mary

2 Andy

3 Peter

4 Russ

Ayrıca bkz.

• CreateDataReader()
• DataTables