Fix Revit API GAP for Preview Visibility

[dfoth]

I'd like to be able to turn on Preview Visibility through the Revit API so that when I bulk upgrade all of my company's Revit Families I can build into my Revit Add-in command that the preview visibility shall be turned on before saving and closing the family. This is super important for the correct creation of preview images for all families.

[dfoth]

Nevermind. Thanks Christoph_Marthaler_AWZH

var uiApp = commandData.Application;
var uiDoc = uiApp.ActiveUIDocument;
var doc = uiDoc.Document;
var activeView = uiDoc.ActiveGraphicalView;

using(var tx = new Transaction(doc))
{
    tx.Start("Set View Mode");
    activeView.TemporaryViewModes.PreviewFamilyVisibility = PreviewFamilyVisibilityMode.On;
    tx.Commit();
}

https://forums.autodesk.com/t5/revit-api-forum/set-preview-visibility-in-family-editor-using-revit-a...