Comment : désérialiser des propriétés de données d'instance
Cette rubrique s'applique à Windows Workflow Foundation 4.
Il peut arriver qu'un utilisateur ou administrateur de workflow veuille inspecter manuellement l'état d'une instance de workflow rendue persistante. SqlWorkflowInstanceStore fournit une vue de la table Instances qui expose les quatre colonnes suivantes :
ReadWritePrimitiveDataProperties
WriteOnlyPrimitiveDataProperties
ReadWriteComplexDataProperties
WriteOnlyComplexDataProperties
Les propriétés des données primitives font référence aux propriétés dont les types .NET Framework sont considérés comme « communs » (par exemple, Int32 et String) alors que les propriétés des données complexes font référence à tous les autres types. Une énumération exacte des types primitifs figure plus loin dans cet exemple de code.
Les propriétés ReadWrite font référence aux propriétés retournées à l'exécution du workflow lorsqu'une instance est chargée. Les propriétés WriteOnly sont écrites dans la base de données et ne sont jamais relues.
Cet exemple fournit un code qui permet à un utilisateur de désérialiser des propriétés des données primitives. Pour un tableau d'octets lu à partir de la colonne ReadWritePrimitiveDataProperties ou WriteOnlyPrimitiveDataProperties, ce code convertira l'objet BLOB en un Dictionary de type <XName, objet> où chaque paire de valeurs de clé représente un nom de propriété et sa valeur correspondante.
Cet exemple ne montre pas comment désérialiser les propriétés des données complexes, car cette opération n'est actuellement pas prise en charge.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.IO.Compression;
using System.Xml.Linq;
using System.Xml;
using System.Globalization;
using System.Data.SqlClient;
namespace PropertyReader
{
class Program
{
const string ConnectionString = @"Data Source=localhost;Initial Catalog=Persistence;Integrated Security=True;Asynchronous Processing=True";
static void Main(string[] args)
{
string queryString = "SELECT TOP 10 * FROM [System.Activities.DurableInstancing].[Instances]";
using (SqlConnection connection =
new SqlConnection(ConnectionString))
{
SqlCommand command =
new SqlCommand(queryString, connection);
connection.Open();
SqlDataReader reader = command.ExecuteReader();
byte encodingOption;
while (reader.Read())
{
if (reader["ReadWritePrimitiveDataProperties"] != DBNull.Value)
{
encodingOption = (byte)reader["EncodingOption"];
Console.WriteLine("Printing the ReadWritePrimitiveDataProperties of the instance with Id:" + reader["InstanceId"]);
foreach (KeyValuePair<XName, object> pair in (Dictionary<XName, object>)ReadDataProperties((byte[])reader["ReadWritePrimitiveDataProperties"], encodingOption))
{
Console.WriteLine("{0}, {1}" , pair.Key, pair.Value);
}
Console.WriteLine();
}
//if (reader["ReadWriteComplexDataProperties"] != DBNull.Value)
//{
// encodingOption = (byte)reader["EncodingOption"];
// Console.WriteLine("Printing the ReadWriteComplexDataProperties of the instance with Id:" + reader["InstanceId"]);
// foreach (KeyValuePair<XName, object> pair in (Dictionary<XName, object>)ReadDataProperties((byte[])reader["ReadWriteComplexDataProperties"], encodingOption))
// {
// Console.WriteLine("{0}, {1}", pair.Key, pair.Value);
// }
// Console.WriteLine();
//}
if (reader["WriteOnlyPrimitiveDataProperties"] != DBNull.Value)
{
encodingOption = (byte)reader["EncodingOption"];
Console.WriteLine("Printing the WriteOnlyPrimitiveDataProperties of the instance with Id:" + reader["InstanceId"]);
foreach (KeyValuePair<XName, object> pair in (Dictionary<XName, object>)ReadDataProperties((byte[])reader["WriteOnlyPrimitiveDataProperties"], encodingOption))
{
Console.WriteLine("{0}, {1}", pair.Key, pair.Value);
}
Console.WriteLine();
}
//if (reader["WriteOnlyComplexDataProperties"] != DBNull.Value)
//{
// encodingOption = (byte)reader["EncodingOption"];
// Console.WriteLine("Printing the WriteOnlyComplexDataProperties of the instance with Id:" + reader["InstanceId"]);
// foreach (KeyValuePair<XName, object> pair in (Dictionary<XName, object>)ReadDataProperties((byte[])reader["WriteOnlyComplexDataProperties"], encodingOption))
// {
// Console.WriteLine("{0}, {1}", pair.Key, pair.Value);
// }
// Console.WriteLine();
//}
}
// Call Close when done reading.
reader.Close();
}
Console.ReadLine();
}
static Dictionary<XName, object> ReadDataProperties(byte[] serializedDataProperties, byte encodingOption)
{
if (serializedDataProperties != null)
{
Dictionary<XName, object> propertyBag = new Dictionary<XName, object>();
bool isCompressed = (encodingOption == 1);
using (MemoryStream memoryStream = new MemoryStream(serializedDataProperties))
{
// if the instance state is compressed using GZip algorithm
if (isCompressed)
{
// decompress the data using the GZip
using (GZipStream stream = new GZipStream(memoryStream, CompressionMode.Decompress))
{
// create an XmlReader object and pass it on to the helper method ReadPrimitiveDataProperties
using (XmlReader reader = XmlDictionaryReader.CreateBinaryReader(stream, XmlDictionaryReaderQuotas.Max))
{
// invoke the helper method
ReadPrimitiveDataProperties(reader, propertyBag);
}
}
}
else
{
// if the instance data is not compressed
// create an XmlReader object and pass it on to the helper method ReadPrimitiveDataProperties
using (XmlReader reader = XmlDictionaryReader.CreateBinaryReader(memoryStream, XmlDictionaryReaderQuotas.Max))
{
// invoke the helper method
ReadPrimitiveDataProperties(reader, propertyBag);
}
}
return propertyBag;
}
}
return null;
}
// reads the primitive data properties from the XML stream
// invoked by the ReadDataProperties method
static void ReadPrimitiveDataProperties(XmlReader reader, Dictionary<XName, object> propertyBag)
{
const string xmlElementName = "Property";
if (reader.ReadToDescendant(xmlElementName))
{
do
{
// get the name of the property
reader.MoveToFirstAttribute();
string propertyName = reader.Value;
// get the type of the property
reader.MoveToNextAttribute();
PrimitiveType type = (PrimitiveType)Int32.Parse(reader.Value, CultureInfo.InvariantCulture);
// get the value of the property
reader.MoveToNextAttribute();
object propertyValue = ConvertStringToNativeType(reader.Value, type);
// add the name and value of the property to the property bag
propertyBag.Add(propertyName, propertyValue);
}
while (reader.ReadToNextSibling(xmlElementName));
}
}
// invoked by the ReadPrimitiveDataProperties method
// Given a property value as parsed from an XML attribute, and the .NET Type of the Property, recreates the actual property value
// (e.g. Given a property value of "1" and a PrimitiveType of Int32, this method will return an object of type Int32 with value 1)
static object ConvertStringToNativeType(string value, PrimitiveType type)
{
switch (type)
{
case PrimitiveType.Bool:
return XmlConvert.ToBoolean(value);
case PrimitiveType.Byte:
return XmlConvert.ToByte(value);
case PrimitiveType.Char:
return XmlConvert.ToChar(value);
case PrimitiveType.DateTime:
return XmlConvert.ToDateTime(value, XmlDateTimeSerializationMode.RoundtripKind);
case PrimitiveType.DateTimeOffset:
return XmlConvert.ToDateTimeOffset(value);
case PrimitiveType.Decimal:
return XmlConvert.ToDecimal(value);
case PrimitiveType.Double:
return XmlConvert.ToDouble(value);
case PrimitiveType.Float:
return float.Parse(value, CultureInfo.InvariantCulture);
case PrimitiveType.Guid:
return XmlConvert.ToGuid(value);
case PrimitiveType.Int:
return XmlConvert.ToInt32(value);
case PrimitiveType.Long:
return XmlConvert.ToInt64(value);
case PrimitiveType.SByte:
return XmlConvert.ToSByte(value);
case PrimitiveType.Short:
return XmlConvert.ToInt16(value);
case PrimitiveType.String:
return value;
case PrimitiveType.TimeSpan:
return XmlConvert.ToTimeSpan(value);
case PrimitiveType.Type:
return Type.GetType(value);
case PrimitiveType.UInt:
return XmlConvert.ToUInt32(value);
case PrimitiveType.ULong:
return XmlConvert.ToUInt64(value);
case PrimitiveType.Uri:
return new Uri(value);
case PrimitiveType.UShort:
return XmlConvert.ToUInt16(value);
case PrimitiveType.XmlQualifiedName:
return new XmlQualifiedName(value);
case PrimitiveType.Null:
case PrimitiveType.Unavailable:
default:
return null;
}
}
// .NET Types which SQL Workflow Instance Store considers to be Primitive. Any other .NET type not listed in this enumeration is a "Complex" property.
enum PrimitiveType
{
Bool = 0,
Byte,
Char,
DateTime,
DateTimeOffset,
Decimal,
Double,
Float,
Guid,
Int,
Null,
Long,
SByte,
Short,
String,
TimeSpan,
Type,
UInt,
ULong,
Uri,
UShort,
XmlQualifiedName,
Unavailable = 99
}
}
}