Revit 2017 Add-In Executing a Custom External Command

Hi

Having some external command issues, seems like my command executes just fine from the Revit UI, but when executed from my add-in there seems to be no exceptions - but the desired result is not achieved.

Thanks to Jeremy Tammik's post Programmatic Custom Add-In External Command Launch  It seems like I am able to execute a custom external command using the UIApplication,.PostCommand by looking up the custom command's revit id using its description (manifest id)

Assemblies

RevitAPI
RevitAPIUI

Namespaces

using Autodesk.Revit.DB;
using Autodesk.Revit.UI;

Custom Addin for External Command...

[Autodesk.Revit.Attributes.Transaction(Autodesk.Revit.Attributes.TransactionMode.ReadOnly)]
public class DocumentSwop : IExternalCommand
{
  public static string filePlaceholderPath = @"\\someserver\C$\somedirectory\PlaceHolder.rvt";

	public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
	{
			Autodesk.Revit.UI.UIApplication uiapp = null;
			Autodesk.Revit.DB.Document doc = null;
			Autodesk.Revit.UI.UIDocument docPlaceHolder = null;
			string filePlaceholder = null;
			string fileRevitActive = null;
			int fileCompare = 0;

			message = "Velocity.Revit.AddIns.DocumentSwop...";

			try
			{
					// Assign UIApplication
					uiapp = commandData.Application;
					message += Environment.NewLine + "  UIApplication object assigned";

					if (uiapp != null)
					{
							message += Environment.NewLine + "  UIApplication not null";

							// Assign curren tactive document
							doc = uiapp.ActiveUIDocument.Document;
							message += Environment.NewLine + "  Current active document object assigned";

							if (doc != null)
							{
									message += Environment.NewLine + "  Document object not null";

									// Continue processing if placeholder file exists
									if (File.Exists(filePlaceholderPath))
									{
											message += Environment.NewLine + "  Placeholder file found in file system for " + filePlaceholderPath;

											// Assign filename of placeholder file
											filePlaceholder = System.IO.Path.GetFileName(filePlaceholderPath);
											message += Environment.NewLine + "  Placeholder File = " + filePlaceholder;

											// Assign filename of current active revit document
											fileRevitActive = doc.Title;
											message += Environment.NewLine + "  Revit Active Document = " + fileRevitActive;

											// Compare files
											fileCompare = String.Compare(filePlaceholder, fileRevitActive);
											message += Environment.NewLine + "  File Compare = " + fileCompare.ToString();

											// Perform document swop out if files dont match
											message += Environment.NewLine + "  Swop Active Document...";
											if (fileCompare != 0)
											{
													docPlaceHolder = uiapp.OpenAndActivateDocument(filePlaceholderPath);
													doc.Close(true);
											}                                
											message += Environment.NewLine + "  Swop Active Document completed";
									}

									message += Environment.NewLine + "Velocity.Revit.AddIns.DocumentSwop completed";
									return Autodesk.Revit.UI.Result.Succeeded;
							}
							else
							{
									message += Environment.NewLine + "  Document object could not be set";
									message += Environment.NewLine + "Velocity.Revit.AddIns.DocumentSwop completed";
									return Autodesk.Revit.UI.Result.Failed;
							}
					}
					else
					{
							message += Environment.NewLine + "  UIApplication object could not be set";
							message += Environment.NewLine + "Velocity.Revit.AddIns.DocumentSwop completed";
							return Autodesk.Revit.UI.Result.Failed;
					}
			}
			catch (Exception ex)
			{
					message += Environment.NewLine + "  Velocity.Revit.AddIns.DocumentSwop exception: " + ex.Message;
					message += Environment.NewLine + "Velocity.Revit.AddIns.DocumentSwop completed";
					return Autodesk.Revit.UI.Result.Failed;
			}
			finally
			{
					filePlaceholder = null;
					fileRevitActive = null;
					fileCompare = 0;
					uiapp = null;
					doc = null;
					docPlaceHolder = null;
			}
	}
}
   

Custom Addin for External Command Manifest...

<?xml version="1.0" encoding="utf-8"?><RevitAddIns><AddIn Type="Command"><Name>Document Swop</Name> <Description>Swop the active document</Description><Text>Document Swop</Text><Assembly>C:\My Addins\DocumentSwop.dll</Assembly> <AddInId>21A8C920-ED49-434A-AACD-176784316B93</AddInId><FullClassName>AddIns.DocumentSwop</FullClassName><VendorId>Vendor Name</VendorId>    <VendorDescription>Vendor Desc</VendorDescription></AddIn> </RevitAddIns>

Custom Addin calling External Command...

private static string comIdCommandDocumentSwop = "21A8C920-ED49-434A-AACD-176784316B93";
Autodesk.Revit.UI.RevitCommandId addinId = null;

try
{
	addinId = RevitCommandId.LookupCommandId(comIdCommandDocumentSwop);
}
catch (Exception ex)
{
	Misc.WriteLog(ex.Message);
}

if (addinId != null)
{
	try
	{
		UIApplication.PostCommand(addinId);
	}
	catch (Exception ex)
	{
		Misc.WriteLog(ex.Message);
	}
}

Seems like the custom external command is executed, but the desired result is not obtained - thus the document swop does not occur.

Anyone have some ideas?

Regards,

Zach