dotnet/maui · critical · InvalidOperationException

call Forms.Init() before this

Error message

call Forms.Init() before this

What it means

Thrown by the ContentPage.CreateSupportFragment extension method when Forms.IsInitialized is false. Creating a SupportFragment for a ContentPage requires the Forms platform to be initialized (registrar, services) so that renderers can be resolved for the page's content. The guard mirrors FormsAppCompatActivity.InternalSetPage's check.

Solutions

1. Call Forms.Init(activity, bundle) in the host Activity's OnCreate before invoking CreateSupportFragment.
2. If using a non-Activity context, ensure Forms was initialized with a valid Activity context earlier in the process.
3. Gate the CreateSupportFragment call behind a check of Forms.IsInitialized and initialize on demand if needed.

Example fix

// before
var fragment = myPage.CreateSupportFragment(this); // throws

// after
protected override void OnCreate(Bundle bundle)
{
    base.OnCreate(bundle);
    Forms.Init(this, bundle);
    var fragment = myPage.CreateSupportFragment(this);
}

if (!Forms.IsInitialized)
    Forms.Init(activity, bundle);
var fragment = page.CreateSupportFragment(context);

When it happens

Trigger: Calling view.CreateSupportFragment(context) from native Android code (e.g., a host Activity or a Fragment that is not a FormsAppCompatActivity) without first calling Forms.Init(context, bundle). Common when embedding a Forms ContentPage inside a native Android app via fragments.

Common situations: Native Android app integrating a single Forms ContentPage and forgetting Forms.Init in the host Activity's OnCreate. Embedding scenarios where the initialization is assumed but skipped. Unit tests calling CreateSupportFragment without bootstrapping Forms.

Related errors

• Call Forms.Init (Activity, Bundle) before this
• Active Shell Item not set. Have you added any Shell Items…
• Activity OnCreate was not called prior to loading the…
• Content not found for active
• Content not found for active

AI-assisted analysis of dotnet/maui@f377ff1c5e (2026-08-13). Data as JSON: /api/errors/22398abba10ba930. Report an issue: GitHub.

Appendix: source

Thrown at src/Compatibility/Core/src/Android/AppCompat/PageExtensions.cs:56

					return;
				}

				_disposed = true;

				if (disposing)
				{
					(_platform as IDisposable)?.Dispose();
				}

				base.Dispose(disposing);
			}
		}
#pragma warning restore 618

		public static Fragment CreateSupportFragment(this ContentPage view, Context context)
		{
			if (!Forms.IsInitialized)
				throw new InvalidOperationException("call Forms.Init() before this");

			if (!(view.RealParent is Application))
			{
				Application app = new DefaultApplication();
				app.MainPage = view;
			}

			var platform = new Platform(context, true);
			platform.SetPage(view);

			var vg = platform.GetViewGroup();

			return new EmbeddedSupportFragment(vg, platform);
		}

		class DefaultApplication : Application
		{
		}

View on GitHub (pinned to f377ff1c5e)