Check if Assembly Views Exist

[a.j_]

I am new to plugin development.  I am trying to create a tool to create new assembly views.  I can create the views just fine.

What I am struggling with is to check if an assembly view already exists in the project and has views/sheets created already.  If so, I'd like to then skip them and create views for the assemblies that need them.  

I tried checking if any of the views had an AssociatedAssemblyInstanceId on it but its not working. 

I would appreciate any help on this.  Thanks

FilteredElementCollector assemblyInstanceCollector = new FilteredElementCollector(doc)
.OfCategory(BuiltInCategory.OST_Assemblies);

List<Element> assemblyInstanceList = assemblyInstanceCollector.OfClass(typeof(AssemblyInstance))
.ToElements().ToList();

FilteredElementCollector viewCollector = new FilteredElementCollector(doc)
.OfCategory(BuiltInCategory.OST_Views);

List<Element> viewList = viewCollector.ToElements().ToList();
foreach (View v in viewList)
{
foreach (Element e1 in assemblyInstanceList)
{
if (e1.Id != v.AssociatedAssemblyInstanceId)
{

var viewSheet = AssemblyViewUtils.CreateSheet(doc, e1.Id, (ElementId)assemblyTileBlock);
var detailSectionH = AssemblyViewUtils.CreateDetailSection(doc, e1.Id, AssemblyDetailViewOrientation.HorizontalDetail);
var elevationTop = AssemblyViewUtils.CreateDetailSection(doc, e1.Id, AssemblyDetailViewOrientation.ElevationTop);
var elevationFront = AssemblyViewUtils.CreateDetailSection(doc, e1.Id, AssemblyDetailViewOrientation.ElevationFront);
var detailSectionB = AssemblyViewUtils.CreateDetailSection(doc, e1.Id, AssemblyDetailViewOrientation.DetailSectionB);

Viewport.Create(doc, viewSheet.Id, elevationTop.Id, new XYZ(.9, 2.2, 0));
Viewport.Create(doc, viewSheet.Id, detailSectionH.Id, new XYZ(.9, 1.5, 0));
Viewport.Create(doc, viewSheet.Id, elevationFront.Id, new XYZ(.9, .9, 0));
Viewport.Create(doc, viewSheet.Id, detailSectionB.Id, new XYZ(2.4, .9, 0));

elevationTop.ViewTemplateId = (ElementId)assemblyViewTemplate;
detailSectionH.ViewTemplateId = (ElementId)assemblyViewTemplate;
elevationFront.ViewTemplateId = (ElementId)assemblyViewTemplate;
detailSectionB.ViewTemplateId = (ElementId)assemblyViewTemplate;
}
}
break;
}

[jeremy_tammik]

Welcome to the Revit API!

This sounds doable. First of all, you might want to explore what the Revit database looks like through the API via RevitLookup:

https://github.com/jeremytammik/RevitLookup

Next, read about how to research to find a Revit API solution:

https://thebuildingcoder.typepad.com/blog/2017/01/virtues-of-reproduction-research-mep-settings-onto...

For instance, you can create a list of all Revit database elements before and after creating such an assembly view. 

By observing those changes you can determine how to address your task.