¿Cómo guardar/restaurar un objeto serializable en/desde un archivo?
Tengo una lista de objetos y necesito guardarla en algún lugar de mi computadora. He leído algunos foros y sé que el objeto tiene que ser Serializable. Pero sería bueno si pudiera conseguir un ejemplo. Por ejemplo si tengo lo siguiente:
[Serializable]
public class SomeClass
{
public string someProperty { get; set; }
}
SomeClass object1 = new SomeClass { someProperty = "someString" };
Pero, ¿cómo puedo almacenarlo object1en algún lugar de mi computadora y luego recuperarlo?
Aceptado
Acabo de escribir una publicación de blog sobre cómo guardar los datos de un objeto en Binary, XML o Json . Tienes razón en que debes decorar tus clases con el atributo [Serializable], pero solo si estás usando serialización binaria. Es posible que prefiera utilizar la serialización XML o Json. Aquí están las funciones para hacerlo en los distintos formatos. Consulte la publicación de mi blog para obtener más detalles.
Actualización: BinaryFormatter ha quedado obsoleto por razones de seguridad y ya no debería utilizarse.
Binario
/// <summary>
/// Writes the given object instance to a binary file.
/// <para>Object type (and all child types) must be decorated with the [Serializable] attribute.</para>
/// <para>To prevent a variable from being serialized, decorate it with the [NonSerialized] attribute; cannot be applied to properties.</para>
/// </summary>
/// <typeparam name="T">The type of object being written to the binary file.</typeparam>
/// <param name="filePath">The file path to write the object instance to.</param>
/// <param name="objectToWrite">The object instance to write to the binary file.</param>
/// <param name="append">If false the file will be overwritten if it already exists. If true the contents will be appended to the file.</param>
public static void WriteToBinaryFile<T>(string filePath, T objectToWrite, bool append = false)
{
using (Stream stream = File.Open(filePath, append ? FileMode.Append : FileMode.Create))
{
var binaryFormatter = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
binaryFormatter.Serialize(stream, objectToWrite);
}
}
/// <summary>
/// Reads an object instance from a binary file.
/// </summary>
/// <typeparam name="T">The type of object to read from the binary file.</typeparam>
/// <param name="filePath">The file path to read the object instance from.</param>
/// <returns>Returns a new instance of the object read from the binary file.</returns>
public static T ReadFromBinaryFile<T>(string filePath)
{
using (Stream stream = File.Open(filePath, FileMode.Open))
{
var binaryFormatter = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
return (T)binaryFormatter.Deserialize(stream);
}
}
XML
Requiere que el ensamblado System.Xml esté incluido en su proyecto.
/// <summary>
/// Writes the given object instance to an XML file.
/// <para>Only Public properties and variables will be written to the file. These can be any type though, even other classes.</para>
/// <para>If there are public properties/variables that you do not want written to the file, decorate them with the [XmlIgnore] attribute.</para>
/// <para>Object type must have a parameterless constructor.</para>
/// </summary>
/// <typeparam name="T">The type of object being written to the file.</typeparam>
/// <param name="filePath">The file path to write the object instance to.</param>
/// <param name="objectToWrite">The object instance to write to the file.</param>
/// <param name="append">If false the file will be overwritten if it already exists. If true the contents will be appended to the file.</param>
public static void WriteToXmlFile<T>(string filePath, T objectToWrite, bool append = false) where T : new()
{
TextWriter writer = null;
try
{
var serializer = new XmlSerializer(typeof(T));
writer = new StreamWriter(filePath, append);
serializer.Serialize(writer, objectToWrite);
}
finally
{
if (writer != null)
writer.Close();
}
}
/// <summary>
/// Reads an object instance from an XML file.
/// <para>Object type must have a parameterless constructor.</para>
/// </summary>
/// <typeparam name="T">The type of object to read from the file.</typeparam>
/// <param name="filePath">The file path to read the object instance from.</param>
/// <returns>Returns a new instance of the object read from the XML file.</returns>
public static T ReadFromXmlFile<T>(string filePath) where T : new()
{
TextReader reader = null;
try
{
var serializer = new XmlSerializer(typeof(T));
reader = new StreamReader(filePath);
return (T)serializer.Deserialize(reader);
}
finally
{
if (reader != null)
reader.Close();
}
}
json
Debe incluir una referencia al ensamblado Newtonsoft.Json, que se puede obtener del paquete Json.NET NuGet .
/// <summary>
/// Writes the given object instance to a Json file.
/// <para>Object type must have a parameterless constructor.</para>
/// <para>Only Public properties and variables will be written to the file. These can be any type though, even other classes.</para>
/// <para>If there are public properties/variables that you do not want written to the file, decorate them with the [JsonIgnore] attribute.</para>
/// </summary>
/// <typeparam name="T">The type of object being written to the file.</typeparam>
/// <param name="filePath">The file path to write the object instance to.</param>
/// <param name="objectToWrite">The object instance to write to the file.</param>
/// <param name="append">If false the file will be overwritten if it already exists. If true the contents will be appended to the file.</param>
public static void WriteToJsonFile<T>(string filePath, T objectToWrite, bool append = false) where T : new()
{
TextWriter writer = null;
try
{
var contentsToWriteToFile = JsonConvert.SerializeObject(objectToWrite);
writer = new StreamWriter(filePath, append);
writer.Write(contentsToWriteToFile);
}
finally
{
if (writer != null)
writer.Close();
}
}
/// <summary>
/// Reads an object instance from an Json file.
/// <para>Object type must have a parameterless constructor.</para>
/// </summary>
/// <typeparam name="T">The type of object to read from the file.</typeparam>
/// <param name="filePath">The file path to read the object instance from.</param>
/// <returns>Returns a new instance of the object read from the Json file.</returns>
public static T ReadFromJsonFile<T>(string filePath) where T : new()
{
TextReader reader = null;
try
{
reader = new StreamReader(filePath);
var fileContents = reader.ReadToEnd();
return JsonConvert.DeserializeObject<T>(fileContents);
}
finally
{
if (reader != null)
reader.Close();
}
}
Ejemplo
// Write the contents of the variable someClass to a file.
WriteToBinaryFile<SomeClass>("C:\someClass.txt", object1);
// Read the file contents back into a variable.
SomeClass object1= ReadFromBinaryFile<SomeClass>("C:\someClass.txt");
Puedes utilizar lo siguiente:
/// <summary>
/// Serializes an object.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="serializableObject"></param>
/// <param name="fileName"></param>
public void SerializeObject<T>(T serializableObject, string fileName)
{
if (serializableObject == null) { return; }
try
{
XmlDocument xmlDocument = new XmlDocument();
XmlSerializer serializer = new XmlSerializer(serializableObject.GetType());
using (MemoryStream stream = new MemoryStream())
{
serializer.Serialize(stream, serializableObject);
stream.Position = 0;
xmlDocument.Load(stream);
xmlDocument.Save(fileName);
}
}
catch (Exception ex)
{
//Log exception here
}
}
/// <summary>
/// Deserializes an xml file into an object list
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="fileName"></param>
/// <returns></returns>
public T DeSerializeObject<T>(string fileName)
{
if (string.IsNullOrEmpty(fileName)) { return default(T); }
T objectOut = default(T);
try
{
XmlDocument xmlDocument = new XmlDocument();
xmlDocument.Load(fileName);
string xmlString = xmlDocument.OuterXml;
using (StringReader read = new StringReader(xmlString))
{
Type outType = typeof(T);
XmlSerializer serializer = new XmlSerializer(outType);
using (XmlReader reader = new XmlTextReader(read))
{
objectOut = (T)serializer.Deserialize(reader);
}
}
}
catch (Exception ex)
{
//Log exception here
}
return objectOut;
}
