PersistenceParticipant.MapValues Method
Definition
Important
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A host invokes this method after it is done with collecting the values in the first stage. The host forwards two read-only dictionaries of values it collected from all persistence participants during the first stage (CollectValues stage) to this method for mapping. The host adds values in the dictionary returned by this method to the collection of write-only values.
protected:
virtual System::Collections::Generic::IDictionary<System::Xml::Linq::XName ^, System::Object ^> ^ MapValues(System::Collections::Generic::IDictionary<System::Xml::Linq::XName ^, System::Object ^> ^ readWriteValues, System::Collections::Generic::IDictionary<System::Xml::Linq::XName ^, System::Object ^> ^ writeOnlyValues);protected virtual System.Collections.Generic.IDictionary<System.Xml.Linq.XName,object> MapValues (System.Collections.Generic.IDictionary<System.Xml.Linq.XName,object> readWriteValues, System.Collections.Generic.IDictionary<System.Xml.Linq.XName,object> writeOnlyValues);abstract member MapValues : System.Collections.Generic.IDictionary<System.Xml.Linq.XName, obj> * System.Collections.Generic.IDictionary<System.Xml.Linq.XName, obj> -> System.Collections.Generic.IDictionary<System.Xml.Linq.XName, obj>
override this.MapValues : System.Collections.Generic.IDictionary<System.Xml.Linq.XName, obj> * System.Collections.Generic.IDictionary<System.Xml.Linq.XName, obj> -> System.Collections.Generic.IDictionary<System.Xml.Linq.XName, obj>Protected Overridable Function MapValues (readWriteValues As IDictionary(Of XName, Object), writeOnlyValues As IDictionary(Of XName, Object)) As IDictionary(Of XName, Object)Parameters
- readWriteValues
- IDictionary<XName,Object>
The read-write values to be persisted.
- writeOnlyValues
- IDictionary<XName,Object>
The write-only values to be persisted.
Returns
A dictionary containing additional write-only values to be persisted.
Examples
The following code sample demonstrates using MapValues in a class that derives from PersistenceParticipant. This example is from the Corporate Purchase Process sample.
class XmlPersistenceParticipant : PersistenceParticipant
{
const string propertiesNamespace = "urn:schemas-microsoft-com:System.Activities/4.0/properties";
private Guid Id;
public XmlPersistenceParticipant(Guid id)
{
Id = id;
}
//Add any additional necessary data to persist here
protected override void CollectValues(out IDictionary<XName, object> readWriteValues, out IDictionary<XName, object> writeOnlyValues)
{
base.CollectValues(out readWriteValues, out writeOnlyValues);
}
//Implementations of MapValues are given all the values collected from all participants’ implementations of CollectValues
protected override IDictionary<XName, object> MapValues(IDictionary<XName, object> readWriteValues, IDictionary<XName, object> writeOnlyValues)
{
XName statusXname = XName.Get("Status", propertiesNamespace);
IDictionary<XName, object> mappedValues = base.MapValues(readWriteValues, writeOnlyValues);
RequestForProposal requestForProposal = null;
string status = string.Empty;
object value = null;
//retrieve the status of the workflow
if (writeOnlyValues.TryGetValue(statusXname, out value))
{
status = (string)value;
}
//retrieve the RequestForProposal object
foreach (KeyValuePair<System.Xml.Linq.XName, object> item in writeOnlyValues)
{
if (item.Value is LocationInfo)
{
LocationInfo li = (LocationInfo)item.Value;
if (li.Value is RequestForProposal)
{
requestForProposal = (RequestForProposal)li.Value;
}
}
}
IOHelper.EnsureAllRfpFileExists();
// load the document
XElement doc = XElement.Load(IOHelper.GetAllRfpsFileName());
IEnumerable<XElement> current =
from r in doc.Elements("requestForProposal")
where r.Attribute("id").Value.Equals(Id.ToString())
select r;
if (status == "Closed")
{
// erase nodes for the current rfp
foreach (XElement xe in current)
{
xe.Attribute("status").Value = "finished";
}
}
else
{
// erase nodes for the current rfp
foreach (XElement xe in current)
{
xe.Remove();
}
// get the Xml version of the Rfp, add it to the document and save it
if (requestForProposal != null)
{
XElement e = SerializeRfp(requestForProposal, Id);
doc.Add(e);
}
}
doc.Save(IOHelper.GetAllRfpsFileName());
return mappedValues;
}
Remarks
Each value provided by implementations of all the MapValues methods across all persistence participants including all the values collected in the first stage (CollectValues stage) must have a unique XName.
