IDataReader.Read 方法

public:
 bool Read();

public bool Read();

abstract member Read : unit -> bool

Public Function Read () As Boolean

傳回

true若行數較多;否則，。 false

範例

以下範例建立了三個導出類別 OleDbConnection的實例，分別為 一個 OleDbCommand、 和 OleDbDataReader一個。 此範例會讀取數據，並將其寫出至主控台。 最後，範例會封 OleDbDataReader閉 ，接著 OleDbConnection。

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

備註

預設 IDataReader 位置位於第一筆紀錄之前。 因此，您必須先打電話 Read 開始存取任何資料。

當資料讀取器正在使用時，相關的連線正忙於服務 IDataReader。 這種情況一直持續到 Close 被叫到。