GetUGridLineIds() returns null

[dmaral]

Hello guys,
I am writing a function that returns GridLines of the selected curtain wall. It is very weird that I can't see all methods and properties of the selected element. In my case it gives me nothing...

using Autodesk.Revit.DB;
using Autodesk.Revit.UI;
using Autodesk.Revit.UI.Selection;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;


namespace Revit.Auswahlhilfe
{
    /// <summary>
    /// Interaktionslogik für FassadenRasterModelView.xaml
    /// </summary>
    public partial class FassadenRasterModelView : Window
    {
        readonly UIDocument document;
        public ExternalEvent ExEvent { get; set; }
        readonly string[] oben_unten = { "Oben -> Unten", "Unten -> Oben" };
        readonly string[] rechts_links = { "Rechts -> Links", "Links -> Rechts" };
        private bool reverse = false;


        public FassadenRasterModelView(UIDocument doc)
        {
            document = doc;
            InitializeComponent();

        }

        private void vertikaleRaster_Checked(object sender, RoutedEventArgs e)
        {
            //horizontaleRaster.IsChecked = false;
            if(labelRichtung != null)
            {
                labelRichtung.Text = rechts_links.First();
                reverse = false;

            }
        }

        private void horizontaleRaster_Checked(object sender, RoutedEventArgs e)
        {
            //vertikaleRaster.IsChecked = false;
            if(labelRichtung != null)
            {
                labelRichtung.Text = oben_unten.First();
                reverse = false;


            }
        }

        private void rasterAuswahl_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                if(ExEvent != null)
                {
                    ExEvent.Raise();
                    Reference selektiertesElement =  document.Selection.PickObject(ObjectType.Element, new FassadenFilter());
                    Document currentDoc = document.Document;
                    Element element = currentDoc.GetElement(selektiertesElement);
                    if (element != null)
                    {
                        rasterAuswahl.Content = element.Name;
                        if (element is Wall)
                        {
                            Wall wall = (Wall)element;
                            CurtainGrid curtainGrid = wall.CurtainGrid;
                            if(curtainGrid != null)
                            {
                                if (vertikaleRaster.IsChecked == true)
                                {
                                    List<ElementId> uGridLines = curtainGrid.GetUGridLineIds() as List<ElementId>;
                                    if (reverse)
                                    {
                                        //IEnumerable<ElementId> ReverseduGridLines = uGridLines.Reverse();
                                        //IList<ElementId> elementsToSelect = (IList<ElementId>)TakeEveryNthItem(ReverseduGridLines.ToList(), ((int)slider.Value), ((int)sliderVersatz.Value));
                                        //document.Selection.SetElementIds(elementsToSelect);
                                    }

                                }
                                if (horizontaleRaster.IsChecked == true)
                                {
                                    ICollection<CurtainGridLine> vGridLines = (ICollection<CurtainGridLine>)curtainGrid.GetVGridLineIds().Select(i => currentDoc.GetElement(i));
                                }
                            }
                            
                        }
                    }
                    else rasterAuswahl.Content = "Fassade auswählen";

                }
            }
            catch
            {

            }
        }
        public static IList TakeEveryNthItem(IList list, int n, int offset = 0)
        {
            return list.Cast<object>().Where((_, i) => (i + 1 - offset) % n == 0).ToList();
        }
        private class FassadenFilter : ISelectionFilter
        {
            public bool AllowElement(Element elem)
            {
                if(elem.Category != null)
                {
                    if(elem is Wall)
                    {
                        Wall wall = (Wall)elem;
                        if(wall.CurtainGrid != null)
                        {
                            return true;
                        }
                    }
                    else if(elem.Category.Id.IntegerValue == (int)BuiltInCategory.OST_Roofs)
                    {
                        FootPrintRoof roof = elem as FootPrintRoof;
                        if(roof != null)
                        {
                            if (roof.CurtainGrids != null)
                            {
                                return true;
                            }
                        }
              
                    }
                }
                return false;
            }

            public bool AllowReference(Reference reference, XYZ position)
            {
                return false;

            }
        }

        private void richtungButton_Click(object sender, RoutedEventArgs e)
        {
            if (vertikaleRaster.IsChecked == true)
            {
                if(reverse == true)
                {
                    labelRichtung.Text = rechts_links.First();
                    reverse = !reverse;
                }
                else
                {
                    labelRichtung.Text = rechts_links.Last();
                    reverse = !reverse;
                }
            }

            if(horizontaleRaster.IsChecked == true)
            {
                if (reverse == true)
                {
                    labelRichtung.Text = oben_unten.First();
                    reverse = !reverse;

                }
                else
                {
                    labelRichtung.Text = oben_unten.Last();
                    reverse = !reverse;

                }

            }
        }
    }

}

it shows me only these properties:

Can you please help me about that?

[mhannonQ65N2]

This is probably because you are casting it to a List<ElementId>. You should just use its actual type (ICollection<ElementId>) or use the var keyword to save some typing.

ICollection<ElementId> uGridLines = curtainGrid.GetUGridLineIds();

[dmaral]

Hello,

thanks for the reply. It did not help in the beginning when I used ICollection. On forum I saw as IList and tried it out.. Same result.

[mhannonQ65N2]

Your breakpoint on line 78 is being hit before line 78 executes so your variable will be null until after it executes. Try setting a breakpoint on line 79 to see the result of line 78.

[dmaral]

If I try to store them in a variable then it is shown as null but if I use curtainGrid.GetUGridLineIds() in a funtion, it works.. :S