Revit API扩展存储Extensible Storage

Revit 2012 API提供扩展存储Extensible Storage 来向revit文件附加数据。
这里是把数据附加到实体，参看附加到项目文件ProjectInfo示例

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using WinForm = System.Windows.Forms;

using Autodesk.Revit.UI;
using Autodesk.Revit.DB;
using Autodesk.Revit.Attributes;

using Autodesk.Revit.DB.Mechanical;
using Autodesk.Revit.UI.Selection;
using Autodesk.Revit.ApplicationServices;

using Autodesk.Revit.DB.Structure;
using Autodesk.Revit.DB.ExtensibleStorage;

using System.Xml;

namespace RevitCodes
{
    [TransactionAttribute(Autodesk.Revit.Attributes.TransactionMode.Manual)]
    public class cmdStore : IExternalCommand
    {
        public Result Execute(ExternalCommandData commandData, ref string messages, ElementSet elements)
        {

            UIApplication app = commandData.Application;
            Document doc = app.ActiveUIDocument.Document;

            Reference refWall = app.ActiveUIDocument.Selection.PickObject(ObjectType.Element, "选择墙");
            Wall wall = doc.GetElement(refWall) as Wall;
            XYZ xyz = app.ActiveUIDocument.Selection.PickPoint("选择一个点");
            StoreDataInWall(wall, xyz);

            return Result.Succeeded;
        }

        public void StoreDataInWall(Wall wall, XYZ dataToStore)
        {

            Transaction createSchemaAndStoreData = new Transaction(wall.Document, "tCreateAndStore");

            createSchemaAndStoreData.Start();

            SchemaBuilder schemaBuilder =

               new SchemaBuilder(new Guid("720080CB-DA99-40DC-9415-E53F280AA1F0"));

            // allow anyone to read the object 

            schemaBuilder.SetReadAccessLevel(AccessLevel.Public);

            // restrict writing to this vendor only 

            schemaBuilder.SetWriteAccessLevel(AccessLevel.Vendor);

            // required because of restricted write-access 

            schemaBuilder.SetVendorId("ADSK");

            // create a field to store an XYZ 

            FieldBuilder fieldBuilder =

               schemaBuilder.AddSimpleField("WireSpliceLocation", typeof(XYZ));

            fieldBuilder.SetUnitType(UnitType.UT_Length);

            fieldBuilder.SetDocumentation("A stored location value representing a wiring splice in a wall.");

            schemaBuilder.SetSchemaName("WireSpliceLocation");

            Schema schema = schemaBuilder.Finish(); // register the Schema object 

            // create an entity (object) for this schema (class) 

            Entity entity = new Entity(schema);

            // get the field from the schema 

            Field fieldSpliceLocation = schema.GetField("WireSpliceLocation");

            entity.Set<XYZ>(fieldSpliceLocation, dataToStore, DisplayUnitType.DUT_METERS); // set the value for this entity 

            wall.SetEntity(entity); // store the entity in the element 

            // get the data back from the wall 

            Entity retrievedEntity = wall.GetEntity(schema);

            XYZ retrievedData =

               retrievedEntity.Get<XYZ>(schema.GetField("WireSpliceLocation"), DisplayUnitType.DUT_METERS);

            createSchemaAndStoreData.Commit();

        }

    }

}

from:http://revit.5d6d.com/thread-1289-1-1.html