HELP! Pick instance & delete category C#

[Anonymous]

I'm still a beginner with C# & Revit API. I would like to have the user start the Macro and have it ask "Please select a Family". I need the Macro to find the Category and delete all of them found in the entire project.

I am stuck on the last entry (see bold) I can't figure out how to have the element selected find the Built-in-Category and delete them all.

namespace DeleteCategory
{
[Autodesk.Revit.Attributes.Transaction(Autodesk.Revit.Attributes.TransactionMode.Manual)]
public class DeleteCategory : IExternalCommand
{
public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
{
//Get application and document objects
UIApplication uiApp = commandData.Application;
Document doc = uiApp.ActiveUIDocument.Document;

//Define a Reference object to accept the pick result
Reference pickedRef = null;

//Pick a Family
Selection sel = uiApp.ActiveUIDocument.Selection;
pickedRef = sel.PickObject(ObjectType.Element, "Please select a Family");
Family fam = Element as FamilyInstance;

[jeremytammik]

I hope you have worked through the getting started material, especially the DevTV and My First Revit Plugin tutorials:

http://thebuildingcoder.typepad.com/blog/about-the-author.html#2

I hope you have the SDK installed and the Revit API help file RevitAPI.chm ready at hand on your desktop.

You can only select a family instance.

The family defines a collection of family types

Each instance placed in the model has a type, which is also called symbol.

The associated classes are called FamilyInstance, FamilySymbol, and Family.

Each of these has a property to retrieve the related object higher up in the relationship tree: instance -> symbol -> family.

The rest of the solution is left to you as a beginner's exercise.

Good luck and have fun!

Best regards,

Jeremy