OleDbDataReader.Read 方法

public:
 override bool Read();

public:
 virtual bool Read();

public override bool Read();

public bool Read();

override this.Read : unit -> bool

abstract member Read : unit -> bool
override this.Read : unit -> bool

Public Overrides Function Read () As Boolean

Public Function Read () As Boolean

返回

true 如果有更多行，则为否则，为 false.

实现

示例

以下示例创建一个 OleDbConnection、一个 OleDbCommand和一个 OleDbDataReader。 该示例读取数据，并将其写出到控制台。 最后，该示例关闭然后关闭 OleDbDataReader 该 OleDbConnection示例。

private static void ReadData(string connectionString)
{
    string queryString = "SELECT OrderID, CustomerID FROM Orders";
    using (OracleConnection connection = new OracleConnection(connectionString))
    {
        OracleCommand command = new OracleCommand(queryString, connection);
        connection.Open();
        OracleDataReader reader;
        reader = command.ExecuteReader();

        // Always call Read before accessing data.
        while (reader.Read())
        {
            Console.WriteLine(reader.GetInt32(0) + ", " + reader.GetString(1));
        }

        // Always call Close when done reading.
        reader.Close();
    }
}

Public Sub ReadData(ByVal connectionString As String)
    Dim queryString As String = _
        "SELECT OrderID, CustomerID FROM Orders"

    Using connection As New OracleConnection(connectionString)
        Dim command As New OracleCommand(queryString, connection)
        connection.Open()

        Dim reader As OracleDataReader
        reader = command.ExecuteReader()

        ' Always call Read before accessing data.
        While reader.Read()
            Console.WriteLine(reader.GetInt32(0) & ", " & reader.GetString(1))
        End While

        ' Always call Close when done reading.
        reader.Close()
    End Using
End Sub

注解

默认位置 OleDbDataReader 位于第一条记录之前。 因此，必须调用 Read 以开始访问任何数据。

在使用时 OleDbDataReader ，关联 OleDbConnection 项正忙于提供服务，直到调用 Close。

另请参阅

• DataAdapter 和 DataReader