FileRegion Sınıf

Tanım

public ref class FileRegion sealed

public sealed class FileRegion

type FileRegion = class

Public NotInheritable Class FileRegion

Devralma

Object

FileRegion

Örnekler

Aşağıdaki örnek, ve FileRegion sınıflarını kullanarak bir günlük deposunun XML'ye nasıl arşivlenip arşivlenileceğini LogStore gösterir.

class LogBackup
{
    static void ArchiveToXML(LogStore logStore, string fileName)
    {

        LogArchiveSnapshot snapshot = logStore.CreateLogArchiveSnapshot();
        {
            XmlTextWriter writer = new XmlTextWriter(fileName, System.Text.Encoding.ASCII);
            writer.WriteStartElement("logArchive");

            foreach (FileRegion region in snapshot.ArchiveRegions)
            {
                writer.WriteStartElement("fileRegion");
                writer.WriteElementString("path",
                                          region.Path);
                writer.WriteElementString("length",
                                        region.FileLength.ToString());
                writer.WriteElementString("offset",
                                          region.Offset.ToString());

                using (Stream dataStream = region.GetStream())
                {
                    byte[] data = new byte[dataStream.Length];
                    dataStream.Read(data, 0, data.Length);

                    writer.WriteElementString("data", System.Convert.ToBase64String(data));
                }

                writer.WriteEndElement();
            }

            writer.Close();
            logStore.SetArchiveTail(snapshot.LastSequenceNumber);
        }
    }

    static void RestoreFromXML(string fileName)
    {
        using (XmlTextReader reader = new XmlTextReader(fileName))
        {
            reader.ReadStartElement("logArchive");
            while (reader.IsStartElement())
            {
                string path;
                long length;
                long offset;
                path = reader.ReadElementString("path");
                length = System.Int64.Parse(reader.ReadElementString("length"));
                offset = System.Int64.Parse(reader.ReadElementString("offset"));
                string dataString = reader.ReadElementString("data");
                byte[] data = System.Convert.FromBase64String(dataString);
                FileStream fileStream;
                using (fileStream = new FileStream(path,
                                              FileMode.OpenOrCreate,
                                              FileAccess.Write))
                {
                    fileStream.SetLength(length);
                    fileStream.Position = offset;
                    fileStream.Write(data, 0, data.Length);
                }
            }
            reader.ReadEndElement();
        }
    }
}

Friend Class LogBackup
    Private Shared Sub ArchiveToXML(ByVal logStore As LogStore, ByVal fileName As String)


        Dim snapshot As LogArchiveSnapshot = logStore.CreateLogArchiveSnapshot()
            Dim writer As New XmlTextWriter(fileName, System.Text.Encoding.ASCII)
            writer.WriteStartElement("logArchive")

        For Each region As FileRegion In snapshot.ArchiveRegions
            With writer
                .WriteStartElement("fileRegion")
                .WriteElementString("path", region.Path)
                .WriteElementString("length", region.FileLength.ToString())
                .WriteElementString("offset", region.Offset.ToString())
            End With

            Using dataStream As Stream = region.GetStream()
                Dim data(dataStream.Length - 1) As Byte
                dataStream.Read(data, 0, data.Length)

                writer.WriteElementString("data", System.Convert.ToBase64String(data))
            End Using

            writer.WriteEndElement()
        Next region

            writer.Close()
            logStore.SetArchiveTail(snapshot.LastSequenceNumber)
    End Sub

    Private Shared Sub RestoreFromXML(ByVal fileName As String)
        Using reader As New XmlTextReader(fileName)
            reader.ReadStartElement("logArchive")
            Do While reader.IsStartElement()
                Dim path As String
                Dim length As Long
                Dim offset As Long
                path = reader.ReadElementString("path")
                length = System.Int64.Parse(reader.ReadElementString("length"))
                offset = System.Int64.Parse(reader.ReadElementString("offset"))
                Dim dataString = reader.ReadElementString("data")
                Dim data() = System.Convert.FromBase64String(dataString)
                Dim fileStream As FileStream
                fileStream = New FileStream(path, FileMode.OpenOrCreate, FileAccess.Write)
                Using fileStream
                    fileStream.SetLength(length)
                    fileStream.Position = offset
                    fileStream.Write(data, 0, data.Length)
                End Using
            Loop
            reader.ReadEndElement()
        End Using
    End Sub
End Class

Açıklamalar

LogArchiveSnapshot Nesnesi, içindeki verilerin LogStoretutarlı bir yedeğini oluşturmak için gereken bilgileri içerir. Gerçek veriler, özelliği tarafından döndürülen nesnelerin numaralandırılabilir koleksiyonunda FileRegionArchiveRegions yer alır. Her FileRegion örnek, arşivlenmiş olması gereken bir dosyadaki bayt dizisini temsil eder.

Özellikler

Yöntemler

Şunlara uygulanır