siga el progreso de carga de enormes archivos XML

Question

Intento seguir el progreso de la carga de grandes archivos XML (no soy el proveedor de estos archivos) en dotnet (C#, framework 3.5 SP1): de 1 MB a 300 MB en un compartir archivos de red

Uso un XmlReader para fines de carga en lugar del método directo XmlDocument.Load para acelerar el proceso de carga.

Por cierto, no encontré en Internet ningún documento sobre cómo seguir este progreso de carga: no parecen existir delegados/eventos. ¿Hay alguna forma de realizar esta tarea? Tener el tipo de funcionalidad para el propósito de guardar XML podría ser algo bueno.

Gracias

Answer 1

Suponiendo que está leyendo de una corriente que aquí hay una (no perfecto) ejemplo de cómo hacerlo ... Básicamente, ProgressStreamWrapper ajusta la secuencia de archivos y genera un evento cada vez que se cambia de posición.

class Program 
{ 
    static void Main(string[] args) 
    { 
     Console.WriteLine("Reading big file..."); 

     FileStream fileStream = File.OpenRead("c:\\temp\\bigfile.xml"); 
     ProgressStreamWrapper progressStreamWrapper = new ProgressStreamWrapper(fileStream); 
     progressStreamWrapper.PositionChanged += (o, ea) => Console.WriteLine((double) progressStreamWrapper.Position/progressStreamWrapper.Length * 100 + "% complete"); 
     XmlReader xmlReader = XmlReader.Create(progressStreamWrapper); 

     while (xmlReader.Read()) 
     { 
      //read the xml document 
     } 

     Console.WriteLine("DONE"); 
     Console.ReadLine(); 
    } 
} 


public class ProgressStreamWrapper : Stream, IDisposable 
{ 
    public ProgressStreamWrapper(Stream innerStream) 
    { 
     InnerStream = innerStream; 
    } 

    public Stream InnerStream { get; private set; } 

    public override void Close() 
    { 
     InnerStream.Close(); 
    } 

    void IDisposable.Dispose() 
    { 
     base.Dispose(); 
     InnerStream.Dispose(); 
    } 

    public override void Flush() 
    { 
     InnerStream.Flush(); 
    } 

    public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, object state) 
    { 
     return InnerStream.BeginRead(buffer, offset, count, callback, state); 
    } 

    public override int EndRead(IAsyncResult asyncResult) 
    { 
     int endRead = InnerStream.EndRead(asyncResult); 
     OnPositionChanged(); 
     return endRead; 
    } 

    public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state) 
    { 
     return InnerStream.BeginWrite(buffer, offset, count, callback, state); 
    } 

    public override void EndWrite(IAsyncResult asyncResult) 
    { 
     InnerStream.EndWrite(asyncResult); 
     OnPositionChanged(); ; 
    } 

    public override long Seek(long offset, SeekOrigin origin) 
    { 
     long seek = InnerStream.Seek(offset, origin); 
     OnPositionChanged(); 
     return seek; 
    } 

    public override void SetLength(long value) 
    { 
     InnerStream.SetLength(value); 
    } 

    public override int Read(byte[] buffer, int offset, int count) 
    { 
     int read = InnerStream.Read(buffer, offset, count); 
     OnPositionChanged(); 
     return read; 
    } 

    public override int ReadByte() 
    { 
     int readByte = InnerStream.ReadByte(); 
     OnPositionChanged(); 
     return readByte; 
    } 

    public override void Write(byte[] buffer, int offset, int count) 
    { 
     InnerStream.Write(buffer, offset, count); 
     OnPositionChanged(); 
    } 

    public override void WriteByte(byte value) 
    { 
     InnerStream.WriteByte(value); 
     OnPositionChanged(); 
    } 

    public override bool CanRead 
    { 
     get { return InnerStream.CanRead; } 
    } 

    public override bool CanSeek 
    { 
     get { return InnerStream.CanSeek; } 
    } 

    public override bool CanTimeout 
    { 
     get { return InnerStream.CanTimeout; } 
    } 

    public override bool CanWrite 
    { 
     get { return InnerStream.CanWrite; } 
    } 

    public override long Length 
    { 
     get { return InnerStream.Length; } 
    } 

    public override long Position 
    { 
     get { return InnerStream.Position; } 
     set 
     { 
      InnerStream.Position = value; 
      OnPositionChanged(); 
     } 
    } 

    public event EventHandler PositionChanged; 

    protected virtual void OnPositionChanged() 
    { 
     if (PositionChanged != null) 
     { 
      PositionChanged(this, EventArgs.Empty); 
     } 
    } 

    public override int ReadTimeout 
    { 
     get { return InnerStream.ReadTimeout; } 
     set { InnerStream.ReadTimeout = value; } 
    } 

    public override int WriteTimeout 
    { 
     get { return InnerStream.WriteTimeout; } 
     set { InnerStream.WriteTimeout = value; } 
    } 
} 

Answer 2

Cómo sobre el uso DataSet.Read()?

o,

// Create the document. 
     XmlDocument doc = new XmlDocument(); 
     doc.Load(file); 

     // Loop through all the nodes, and create the list of Product objects . 
     List<Product> products = new List<Product>(); 

     foreach (XmlElement element in doc.DocumentElement.ChildNodes) 
     { 
      Product newProduct = new Product(); 
      newProduct.ID = Int32.Parse(element.GetAttribute("ID")); 
      newProduct.Name = element.GetAttribute("Name"); 

      // If there were more than one child node, you would probably use 
      // another For Each loop here and move through the 
      // Element.ChildNodes collection. 
      newProduct.Price = Decimal.Parse(element.ChildNodes[0].InnerText); 

      products.Add(newProduct); 
     } 

Answer 3

Con los cargadores incorporados no hay mucho; Sin embargo, podría escribir una secuencia de interceptación: cargue su documento desde esta secuencia y exponga el Position a través de eventos. es decir, plantear un evento en el método Read (a intervalos)?

---

Aquí hay un ejemplo que soporta actualizaciones durante tanto leer y escribir:

using System; 
using System.IO; 
using System.Xml; 
class ChattyStream : Stream 
{ 
    private Stream baseStream; 
    public ChattyStream(Stream baseStream) 
    { 
     if (baseStream == null) throw new ArgumentNullException("baseStream"); 
     this.baseStream = baseStream; 
     updateInterval = 1000; 
    } 
    public event EventHandler ProgressChanged; 
    protected virtual void OnProgressChanged() 
    { 
     var handler = ProgressChanged; 
     if (handler != null) handler(this, EventArgs.Empty); 
    } 
    private void CheckDisposed() 
    { 
     if (baseStream == null) throw new ObjectDisposedException(GetType().Name); 
    } 
    protected Stream BaseStream 
    { 
     get { CheckDisposed(); return baseStream; } 
    } 
    int pos, updateInterval; 
    public int UpdateInterval 
    { 
     get { return updateInterval; } 
     set 
     { 
      if (value <= 0) throw new ArgumentOutOfRangeException("value"); 
      updateInterval = value; 
     } 
    } 

    protected void Increment(int value) 
    { 
     if (value > 0) 
     { 
      pos += value; 
      if (pos >= updateInterval) 
      { 
       OnProgressChanged(); 
       pos = pos % updateInterval; 
      } 
     } 
    } 
    public override int Read(byte[] buffer, int offset, int count) 
    { 
     int result = BaseStream.Read(buffer, offset, count); 
     Increment(result); 
     return result; 
    } 
    public override void Write(byte[] buffer, int offset, int count) 
    { 
     BaseStream.Write(buffer, offset, count); 
     Increment(count); 
    } 
    public override void SetLength(long value) 
    { 
     BaseStream.SetLength(value); 
    } 
    public override void Flush() 
    { 
     BaseStream.Flush(); 
    } 
    public override long Position 
    { 
     get { return BaseStream.Position; } 
     set { BaseStream.Position = value; } 
    } 
    public override long Seek(long offset, SeekOrigin origin) 
    { 
     return BaseStream.Seek(offset, origin); 
    } 
    public override long Length 
    { 
     get { return BaseStream.Length; } 
    } 
    public override bool CanWrite 
    { 
     get { return BaseStream.CanWrite; } 
    } 
    public override bool CanRead 
    { 
     get { return BaseStream.CanRead; } 
    } 
    public override bool CanSeek 
    { 
     get { return BaseStream.CanSeek; } 
    } 
    protected override void Dispose(bool disposing) 
    { 
     if (disposing && baseStream != null) 
     { 
      baseStream.Dispose(); 
     } 
     baseStream = null; 
     base.Dispose(disposing); 
    } 
    public override void Close() 
    { 
     if (baseStream != null) baseStream.Close(); 
     base.Close(); 
    } 
    public override int ReadByte() 
    { 
     int val = BaseStream.ReadByte(); 
     if (val >= 0) Increment(1); 
     return val; 
    } 
    public override void WriteByte(byte value) 
    { 
     BaseStream.WriteByte(value); 
     Increment(1); 
    } 

} 
static class Program 
{ 
    static void Main() 
    { 
     /* invent some big data */ 
     const string path = "bigfile"; 
     if (File.Exists(path)) File.Delete(path); 
     using (var chatty = new ChattyStream(File.Create(path))) 
     { 
      chatty.ProgressChanged += delegate 
      { 
       Console.WriteLine("Writing: " + chatty.Position); 
      }; 
      using (var writer = XmlWriter.Create(chatty)) 
      { 
       writer.WriteStartDocument(); 
       writer.WriteStartElement("xml"); 
       for (int i = 0; i < 50000; i++) 
       { 
        writer.WriteElementString("add", i.ToString()); 
       } 
       writer.WriteEndElement(); 
       writer.WriteEndDocument(); 
      } 
      chatty.Close(); 
     } 


     /* read it */ 

     using (var chatty = new ChattyStream(File.OpenRead("bigfile"))) 
     { 
      chatty.ProgressChanged += delegate 
      { 
       Console.WriteLine("Reading: " + chatty.Position); 
      }; 

      // now read "chatty" with **any** API; XmlReader, XmlDocument, XDocument, etc 
      XmlDocument doc = new XmlDocument(); 
      doc.Load(chatty); 
     } 
    } 
}