revit api扩展存储extensible storage

    public Result Execute(
      ExternalCommandData commandData,
      ref string message,
      ElementSet elements)
    {
      UIDocument uiDoc = commandData.Application.ActiveUIDocument;
      Document doc = uiDoc.Document;
 
      // Create transaction for working with schema
 
      Transaction trans = new Transaction(doc, "Extensible Storage");
      trans.Start();
 
      // Select a wall element
 
      Wall wall = null;
 
      try
      {
        Reference r = uiDoc.Selection.PickObject(ObjectType.Element,
          new WallSelectionFilter());
 
        wall = doc.GetElement(r) as Wall;
      }
      catch (Autodesk.Revit.Exceptions.OperationCanceledException)
      {
        message = "Nothing selected; please select a wall to attach extensible data to.";
        return Result.Failed;
      }
 
      Debug.Assert(null != wall, "expected a wall to be selected");
 
      if (null == wall)
      {
        message = "Please select a wall to attach extensible data to.";
        return Result.Failed;
      }
 
      // Create a schema builder
 
      SchemaBuilder builder = new SchemaBuilder(_guid);
 
      // Set read and write access levels
 
      builder.SetReadAccessLevel(AccessLevel.Public);
      builder.SetWriteAccessLevel(AccessLevel.Public);
 
      // Note: if this was set as vendor or application access, 
      // we would have been additionally required to use SetVendorId
 
      // Set name to this schema builder
 
      builder.SetSchemaName("WallSocketLocation");
      builder.SetDocumentation("Data store for socket related info in a wall");
 
      // Create field1
 
      FieldBuilder fieldBuilder1 =
        builder.AddSimpleField("SocketLocation", typeof(XYZ));
 
      // Set unit type
 
      fieldBuilder1.SetUnitType(UnitType.UT_Length);
 
      // Add documentation (optional)
 
      // Create field2
 
      FieldBuilder fieldBuilder2 =
        builder.AddSimpleField("SocketNumber", typeof(string));
 
      //fieldBuilder2.SetUnitType(UnitType.UT_Custom);
 
      // Register the schema object
 
      Schema schema = builder.Finish();
 
      // Create an entity (object) for this schema (class)
 
      Entity ent = new Entity(schema);
      Field socketLocation = schema.GetField("SocketLocation");
      ent.Set<XYZ>(socketLocation, new XYZ(2, 0, 0), DisplayUnitType.DUT_METERS);
 
      Field socketNumber = schema.GetField("SocketNumber");
      ent.Set<string>(socketNumber, "200");
 
      wall.SetEntity(ent);
 
      // Now create another entity (object) for this schema (class)
 
      Entity ent2 = new Entity(schema);
      Field socketNumber1 = schema.GetField("SocketNumber");
      ent2.Set<String>(socketNumber1, "400");
      wall.SetEntity(ent2);
 
      // Note: this will replace the previous entity on the wall 
 
      // List all schemas in the document
 
      string s = string.Empty;
      IList<Schema> schemas = Schema.ListSchemas();
      foreach (Schema sch in schemas)
      {
        s += "\r\nSchema Name: " + sch.SchemaName;
      }
      TaskDialog.Show("Schema details", s);
 
      // List all Fields for our schema
 
      s = string.Empty;
      Schema ourSchema = Schema.Lookup(_guid);
      IList<Field> fields = ourSchema.ListFields();
      foreach (Field fld in fields)
      {
        s += "\r\nField Name: " + fld.FieldName;
      }
      TaskDialog.Show("Field details", s);
 
      // Extract the value for the field we created
 
      Entity wallSchemaEnt = wall.GetEntity(Schema.Lookup(_guid));
 
      XYZ wallSocketPos = wallSchemaEnt.Get<XYZ>(
        Schema.Lookup(_guid).GetField("SocketLocation"),
        DisplayUnitType.DUT_METERS);
 
      s = "SocketLocation: " + Format.PointString(wallSocketPos);
 
      string wallSocketNumber = wallSchemaEnt.Get<String>(
        Schema.Lookup(_guid).GetField("SocketNumber"));
 
      s += "\r\nSocketNumber: " + wallSocketNumber;
 
      TaskDialog.Show("Field values", s);
 
      trans.Commit();
 
      return Result.Succeeded;
    }