PersistenceParticipant.MapValues Method

Definition

Namespace:

System.Activities.Persistence

Assembly:

System.Activities.dll

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

IDictionary<XName,Object>

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.