added 'Snippets_PassCategoryAndClassAsVariables.cs' to 1-csharp-code

Author: dnenov

1-csharp-code/Snippets_PassCategoryAndClassAsVariables.cs

@@ -0,0 +1,36 @@
+/*
+Pass Category and Class as Variables
+This snippet shows how to programatically extract the BuiltInCategory and Class Type 
+information from an element and pass it to a FilteredElementCollector
+
+It is useful when working with generic elements without knowing their category or class ahead of time
+or as a demonstration of BuiltInCategory and typeof(System.Type) concepts
+
+TESTED REVIT API: 2017
+The snippet can be used as is in a Revit Application Macro for test purposes
+
+Author: Deyan Nenov | github.com/ArchilizerLtd
+
+This file is shared on www.revitapidocs.com
+For more information visit http://github.com/gtalarico/revitapidocs
+License: http://github.com/gtalarico/revitapidocs/blob/master/LICENSE.md
+*/
+
+public void PassCategoryAndClassAsVariables()
+{
+	UIDocument uidoc = this.ActiveUIDocument;
+	Document doc = uidoc.Document;
+	
+	var element = doc.GetElement(uidoc.Selection.PickObject(ObjectType.Element, "Pick test subject").ElementId);
+	var type = element.GetType();	//if a Wall element is picked, this substiutes *typeof(Wall)* 
+	var bic = (BuiltInCategory)element.Category.Id.IntegerValue	//if a Wall element is picked, this substitutes *BuiltInCategory.OST_Walls*
+	
+	FilteredElementCollector collector 
+	      = new FilteredElementCollector( doc );
+	
+	collector.OfCategory(bic);
+	collector.OfClass(type);
+     
+	// Select all elements of the same Category and Class
+	uidoc.Selection.SetElementIds( collector.ToElementIds() );
+}