Internal method IsInAPIContext in Revit 2027

[ricaun]

I was doing some snoop around in Revit 2027 API and noticed the internal method IsInAPIContext.

So your implementation could be replaces in Revit 2027 using UnsafeAccessor.

extension(Application application)
{
    [UnsafeAccessor(UnsafeAccessorKind.Method, Name = "IsInAPIContext")]
    public extern bool IsInAPIContext();
}

Another thing that caught my eyes was your current implementation, uses the assembly APIUIAPI, and I know you could replace with RevitDBAPI to make possible to know the context without the Revit UI, the same internal methods exist in RevitDBAPI.

RevitToolkit/source/Nice3point.Revit.Toolkit/RevitContext.cs

Lines 26 to 33 in b5abec5

	var assemblies = FindAssemblies("APIUIAPI", "RevitAPIUI");
	var apiAssemblyMethods = assemblies[0].ManifestModule.GetMethods(BindingFlags.NonPublic | BindingFlags.Static);
	var apiCallDepthManagerMethod = apiAssemblyMethods.FirstOrDefault(static method => method.Name == "APICallDepthManager.singletonfactory");
	ThrowWhen(apiCallDepthManagerMethod is null);
	var isRevitInApiModeMethod = apiAssemblyMethods.FirstOrDefault(static method => method.Name == "APICallDepthManager.isRevitInAPIMode");
	ThrowWhen(isRevitInApiModeMethod is null);

Here is a full implementation with some basic test using your RevitApiTest.

using Autodesk.Revit.ApplicationServices;
using Nice3point.TUnit.Revit;
using System.Reflection;
using System.Runtime.CompilerServices;

namespace RevitTests.Test
{
    public sealed class RevitContextTests : RevitApiTest
    {
        [Test]
        public async Task IsInAPIContext_ReturnTrue()
        {
            var isInAPIContext = Application.IsInAPIContext();
            await Assert.That(isInAPIContext).IsTrue();
        }

        [Test]
        public async Task IsInAPIContext_InsideTask_ReturnFalse()
        {
            var isInAPIContext = Task.Run(async () => Application.IsInAPIContext()).GetAwaiter().GetResult();
            await Assert.That(isInAPIContext).IsFalse();
        }
    }

    public static class ApplicationExtension
    {
#if !REVIT2027_OR_GREATER
        private static readonly Func<bool> GetIsRevitInApiMode;
        static ApplicationExtension()
        {
            var revitDBAPI = AppDomain.CurrentDomain.GetAssemblies().FirstOrDefault(e => e.GetName().Name == "RevitDBAPI");
            var dbAssemblyMethods = revitDBAPI.ManifestModule.GetMethods(BindingFlags.NonPublic | BindingFlags.Static);
            var apiCallDepthManagerMethod = dbAssemblyMethods.FirstOrDefault(static method => method.Name == "APICallDepthManager.singletonfactory");
            var isRevitInApiModeMethod = dbAssemblyMethods.FirstOrDefault(static method => method.Name == "APICallDepthManager.isRevitInAPIMode");

            GetIsRevitInApiMode = () =>
            {
                var apiCallDepthManager = apiCallDepthManagerMethod.Invoke(null, null);
                return (bool)isRevitInApiModeMethod.Invoke(null, [apiCallDepthManager])!;
            };
        }
#endif

        extension(Application application)
        {
#if REVIT2027_OR_GREATER
            [UnsafeAccessor(UnsafeAccessorKind.Method, Name = "IsInAPIContext")]
            public extern bool IsInAPIContext();
#else
            public bool IsInAPIContext() => GetIsRevitInApiMode();
#endif
        }
    }
}

[Nice3point]

Thats nice 😊 61,96 ns/112b -> 27,43 ns/0b. Autodesk working on something ?

i found another one, a new static property, but its an Instance? allocation per call to create a wrapper from Application ? Application always suppose to be a singleton:

#if REVIT2027_OR_GREATER

    [UnsafeAccessor(UnsafeAccessorKind.StaticMethod, Name = "get_Instance")]
    internal static extern UIApplication GetUiApplicationInstance(UIApplication? target);
#endif

[Nice3point]

#130

I think it makes sense to keep IsInAPIContext in the UI context. It is helpful where ExternalEvent is available; for headless Design Automation this property does nothing

Revit 2027, IsInAPIContext result and transaction start:

Called from	RevitApiTest	RevitApiUiTest
Revit thread	true, starts	true, starts
Task.Run	false, fails	false, fails
Revit thread, queued with Dispatcher.BeginInvoke	true, starts	false, fails

• With the UI, the Revit thread can run outside the API context. A thread check misses this case.
• Headless, the Revit thread is always in the API context. A thread check is enough.

[ricaun]

Thats nice 😊 61,96 ns/112b -> 27,43 ns/0b. Autodesk working on something ?

I found basically this inside some Autodesk implementation:

// Autodesk.Revit.UI.UIApplication.Instance?.Application?.IsInAPIContext()

i found another one, a new static property, but its an Instance? allocation per call to create a wrapper from Application ? Application always suppose to be a singleton:

To get the UIApplication I usually use this:

UIApplication uiApplicaiton = new Autodesk.Revit.UI.Events.RibbonItemEventArgs().Application;

That's basically what the Instance is doing.
The problem that the Application and UIApplication have the interface IDisposable. Someone could dispose your singleton and probably something bad gonna happen.