Revit API Option Handlers

Revit API Option Handlers

Several Revit API calls demand a small callback interface. Nice3point.Revit.Toolkit ships ready implementations with a default behavior and lambda or enum customization. A hand-rolled implementation of the interface is unnecessary.

When to use

• A Revit API call requires IFamilyLoadOptions, IDuplicateTypeNamesHandler, or ISaveSharedCoordinatesCallback.

Workflow

Step 1: Family load options

document.LoadFamily(fileName, new FamilyLoadOptions(), out var family); //overwrite existing types, load from the family
document.LoadFamily(fileName, new FamilyLoadOptions(false, FamilySource.Project), out var family); // keep values, load from the project
document.LoadFamily(fileName, UIDocument.GetRevitUIFamilyLoadOptions(), out var family); //reuse Revit's interactive prompt

The default constructor overwrites the parameter values of existing types; the (overwrite, FamilySource) constructor sets those explicitly, and UIDocument.GetRevitUIFamilyLoadOptions() defers to Revit's own dialog.

Step 2: Duplicate type names handler

var options = new CopyPasteOptions();
options.SetDuplicateTypeNamesHandler(new DuplicateTypeNamesHandler()); //default: UseDestinationTypes
options.SetDuplicateTypeNamesHandler(new DuplicateTypeNamesHandler(DuplicateTypeAction.Abort)); //fixed action
options.SetDuplicateTypeNamesHandler(new DuplicateTypeNamesHandler(args => DuplicateTypeAction.Abort)); // decide per call

The default constructor keeps the destination types; pass a DuplicateTypeAction for a fixed action, or a lambda that returns the action per call from the args.

Step 3: Save shared coordinates callback

linkType.Unload(new SaveSharedCoordinatesCallback()); //default: SaveLinks
linkType.Unload(new SaveSharedCoordinatesCallback(SaveModifiedLinksOptions.DoNotSaveLinks)); //fixed option
linkType.Unload(new SaveSharedCoordinatesCallback(link => //decide per link
{
    if (link.AttachmentType == AttachmentType.Overlay) return SaveModifiedLinksOptions.SaveLinks;
    return SaveModifiedLinksOptions.DoNotSaveLinks;
}));

The default constructor saves the links; pass a SaveModifiedLinksOptions value for a fixed choice, or a lambda that returns the option per link.

Step 4: Verify

Call the API with the handler and confirm the intended behavior applies — the family loads with the chosen source, the duplicate resolves as selected, or the link unloads with the chosen coordinate option.

Validation

• The callback uses the Toolkit handler, not a hand-rolled interface implementation.
• Customization is expressed with the lambda or enum overload, not a new class.
• The selected default behavior matches the operation's requirement.

Common Pitfalls