topic Re: How to filter selection set for "Curve"? in .NET Forum

How to filter selection set for "Curve"?

danielmollerX5W2N — Mon, 17 Jan 2022 13:50:50 GMT

I know how to filter a selection set for a specific type, such as "Polyline", or "Circle".

But how can I make a filter that can accept any "Curve"? (All kinds of objects in Autocad .NET that are derived from "Curve").

I have a very simple method to solve this for an "exact" type, but it doesn't work for a "derived" type:

public static SelectionFilter New<T>() where T: Entity { RXClass type = RXClass.GetClass(typeof(T)); SelectionFilter result = new SelectionFilter(new TypedValue[] { new TypedValue((int)DxfCode.Start, type.DxfName) }); return result; }

Re: How to filter selection set for "Curve"?

_gile — Mon, 17 Jan 2022 14:26:49 GMT

Hi,

You can explicitly specify all curve entities in the selection filter (take care to avoid the meshes which also use the "POLYLINE" DXF group)

var filter = new SelectionFilter(new[] { new TypedValue(-4, "<OR"), new TypedValue(0, "ARC,CIRCLE,ELLIPSE,LEADER,LINE,LWPOLYLINE,RAY,SPLINE,XLINE"), new TypedValue(-4, "<AND"), new TypedValue(0, "POLYLINE"), new TypedValue(-4, "&"), new TypedValue(70, 16 | 32 | 64), new TypedValue(-4, "AND>"), new TypedValue(-4, "OR>") });

Another way should be handling the Editor.SelectionAdded event

static void OnSelectionAdded(object sender, SelectionAddedEventArgs e) { var curveClass = RXObject.GetClass(typeof(Curve)); var ids = e.AddedObjects.GetObjectIds(); for (int i = 0; i < ids.Length; i++) { if (!ids[i].ObjectClass.IsDerivedFrom(curveClass)) e.Remove(i); } }

using:

ed.SelectionAdded += OnSelectionAdded; PromptSelectionResult selectionResult = ed.GetSelection(); ed.SelectionAdded -= OnSelectionAdded;

Re: How to filter selection set for "Curve"?

danielmollerX5W2N — Mon, 17 Jan 2022 14:59:35 GMT

Great! Thank you!

For safety, I inverted the loop in the event handler, doesn't removing by index corrupt indexing?

Re: How to filter selection set for "Curve"?

_gile — Mon, 17 Jan 2022 15:43:10 GMT

@danielmollerX5W2N a écrit :

For safety, I inverted the loop in the event handler, doesn't removing by index corrupt indexing?

From the tests I did (and i use it for a while) it does not corrupt indexing.