BuildingCoder.CmdNewCrossFitting.Execute C# (CSharp) Method

        public Result Execute(
            ExternalCommandData commandData,
            ref string message,
            ElementSet elements)
        {
            UIApplication app = commandData.Application;
              UIDocument uidoc = app.ActiveUIDocument;
              Document doc = uidoc.Document;

              IList<Element> pipes = null;
              int n = 0;

              // Ensure that 2, 3 or 4 pipes are selected.

              while( n < 2 || 4 < n )
              {
            if( 0 != n )
            {
              Util.InfoMsg( string.Format(
            "You picked {0} pipe{1}. "
            + "Please only pick 2, 3 or 4.",
            n, Util.PluralSuffix( n ) ) );
            }

            try
            {
              Selection sel = app.ActiveUIDocument.Selection;

              pipes = sel.PickElementsByRectangle(
            new JtElementsOfClassSelectionFilter<Pipe>(),
            "Please pick some pipes." );
            }
            catch( Autodesk.Revit.Exceptions
              .InvalidOperationException )
            {
              return Result.Cancelled;
            }
            n = pipes.Count;
              }

              XYZ pt = null;

              using( Transaction tx = new Transaction( doc ) )
              {
            tx.Start( "CreateConnector" );
            if( pipes.Count() <= 1 )
              return Result.Cancelled;

            Pipe pipe1 = pipes[0] as Pipe;
            Pipe pipe2 = pipes[1] as Pipe;

            Curve curve1 = pipe1.GetCurve();
            Curve curve2 = pipe2.GetCurve();

            XYZ p1 = curve1.GetEndPoint( 0 );
            XYZ q1 = curve1.GetEndPoint( 1 );

            XYZ p2 = curve2.GetEndPoint( 0 );
            XYZ q2 = curve2.GetEndPoint( 1 );

            if( q1.DistanceTo( p2 ) < 0.1 )
            {
              pt = ( q1 + p2 ) * 0.5;
            }
            else if( q1.DistanceTo( q2 ) < 0.1 )
            {
              pt = ( q1 + q2 ) * 0.5;
            }
            else if( p1.DistanceTo( p2 ) < 0.1 )
            {
              pt = ( p1 + p2 ) * 0.5;
            }
            else if( p1.DistanceTo( q2 ) < 0.1 )
            {
              pt = ( p1 + q2 ) * 0.5;
            }
            else
            {
              message = "Please select two pipes "
            + "with near-by endpoints.";

              return Result.Failed;
            }

            Connector c1 = Util.GetConnectorClosestTo(
              pipe1, pt );

            Connector c2 = Util.GetConnectorClosestTo(
              pipe2, pt );

            if( pipes.Count() == 2 )
            {
              if( IsPipeParallel( pipe1, pipe2 ) == true )
              {
            doc.Create.NewUnionFitting( c1, c2 );
              }
              else
              {
            doc.Create.NewElbowFitting( c1, c2 );
              }
            }
            else if( pipes.Count() == 3 )
            {
              Pipe pipe3 = pipes[2] as Pipe;

              XYZ v1 = GetPipeDirection( pipe1 );
              XYZ v2 = GetPipeDirection( pipe2 );
              XYZ v3 = GetPipeDirection( pipe3 );

              Connector c3 = Util.GetConnectorClosestTo(
            pipe3, pt );

              if( Math.Sin( v1.AngleTo( v2 ) ) < 0.01 ) //平行
              {
            doc.Create.NewTeeFitting( c1, c2, c3 );
              }
              else //v1, 和v2 垂直.
              {
            if( Math.Sin( v3.AngleTo( v1 ) ) < 0.01 ) //v3, V1 平行
            {
              doc.Create.NewTeeFitting( c3, c1, c2 );
            }
            else //v3, v2 平行
            {
              doc.Create.NewTeeFitting( c3, c2, c1 );
            }
              }
            }
            else if( pipes.Count() == 4 )
            {
              Pipe pipe3 = pipes[2] as Pipe;
              Pipe pipe4 = pipes[3] as Pipe;

              Connector c3 = Util.GetConnectorClosestTo(
            pipe3, pt );

              Connector c4 = Util.GetConnectorClosestTo(
            pipe4, pt );

              //以从哪c1为入口.

              // The required connection order for a cross
              // fitting is main – main – side - side.

              if( IsPipeParallel( pipe1, pipe2 ) )
              {
            doc.Create.NewCrossFitting(
              c1, c2, c3, c4 );
              }
              else if( IsPipeParallel( pipe1, pipe3 ) )
              {
            try
            {
              doc.Create.NewCrossFitting(
                c1, c3, c2, c4 );
            }
            catch( Exception ex )
            {
              TaskDialog.Show(
                "Cannot insert cross fitting",
                ex.Message );
            }
              }
              else if( IsPipeParallel( pipe1, pipe4 ) )
              {
            doc.Create.NewCrossFitting(
              c1, c4, c2, c3 );
              }
            }
            tx.Commit();
              }
              return Result.Succeeded;
        }