PersistenceParticipant.MapValues 方法

定义

命名空间:
System.Activities.Persistence
程序集:
System.Activities.dll

主机在完成收集第一阶段中的值后调用此方法。 主机将第一阶段（CollectValues 阶段）从所有持久性参与者收集的值的两个只读字典转发到此方法进行映射。 主机将此方法返回的字典中的值添加到只写值的集合中。

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)

参数

readWriteValues
IDictionary<XName,Object>

要保留的读写值。

writeOnlyValues
IDictionary<XName,Object>

要持久保存的仅写值。

返回

IDictionary<XName,Object>

包含要持久保存的其他只写值的字典。

示例

下面的代码示例演示如何在派生自 PersistenceParticipant的类中使用 MapValues。 此示例来自 公司购买过程 示例。

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;
    }

注解

所有持久性参与者（包括第一阶段（CollectValues 阶段）中收集的所有值在内的所有 MapValues 方法的实现提供的每个值都必须具有唯一的 XName。

适用于