What causes "{GetType().FullName}" in HangfireIO/Hangfire?

Stop all consumers of the scheduler before calling Dispose(); use a cancellation token to wind down worker queries.

HangfireIO/Hangfire · error · ObjectDisposedException

{GetType().FullName}

Error message

{GetType().FullName}

What it means

Thrown by BackgroundTaskScheduler.ThrowIfDisposed (an ObjectDisposedException with the type's full name) when an operation is attempted after Dispose(). The scheduler sets _disposed=1 in Dispose() and releases its wait handles; continued use after that is undefined.

Source

Thrown at src/Hangfire.Core/Processing/BackgroundTaskScheduler.cs:347

                handler?.Invoke(exception);
            }
#if !NETSTANDARD1_3
            catch (Exception ex) when (ex.IsCatchableExceptionType())
            {
                Trace.WriteLine("Unexpected exception caught in exception handler itself." + Environment.NewLine + ex);
            }
#else
            catch
            {
            }
#endif
        }

        private void ThrowIfDisposed()
        {
            if (Volatile.Read(ref _disposed) == 1)
            {
                throw new ObjectDisposedException(GetType().FullName);
            }
        }
    }
}

View on GitHub (pinned to c236dd0f93)

Solutions

Stop all consumers of the scheduler before calling Dispose(); use a cancellation token to wind down worker queries.
Catch ObjectDisposedException at call sites that may race with shutdown and treat it as 'no tasks'.
Avoid calling GetScheduledTasks for diagnostics on a scheduler that may be disposed — snapshot liveness another way.

Example fix

// before
var tasks = scheduler.GetScheduledTasks(); // throws if disposed

// after
IEnumerable<Task> tasks;
try { tasks = scheduler.GetScheduledTasks(); }
catch (ObjectDisposedException) { tasks = Enumerable.Empty<Task>(); }

Defensive patterns

Strategy: try-catch

Validate before calling

if (_disposed == 1) return Enumerable.Empty<Task>();
return scheduler.GetScheduledTasks();

Try / catch

IEnumerable<Task> tasks;
try { tasks = scheduler.GetScheduledTasks(); }
catch (ObjectDisposedException) { tasks = Enumerable.Empty<Task>(); }

Prevention

Tear down all consumers (diagnostics, monitors) before disposing the scheduler.
Use a cancellation token to signal shutdown so queries stop before Dispose().
Never query a scheduler whose lifetime is owned by a using-block.

When it happens

Trigger: Calling GetScheduledTasks (or any path through ThrowIfDisposed) on a BackgroundTaskScheduler after Dispose() was invoked. Commonly a shutdown race where one thread disposes while another queries scheduled tasks.

Common situations: Application shutdown disposes the scheduler while a diagnostics/monitoring thread enumerates scheduled tasks; a using-block scopes the scheduler too narrowly; double-handling where Dispose runs early due to an exception.

Related errors

AI-assisted analysis of HangfireIO/Hangfire@c236dd0f93 (2026-08-13). Data as JSON: /api/errors/3d77868c2a0423ad. Report an issue: GitHub.