AvaloniaUI/Avalonia · warning · InvalidOperationException

Handle is not initialized.

Error message

Handle is not initialized.

What it means

Centralized ThrowHelper.ThrowInvalidOperationException_HandleIsNotInitialized throws InvalidOperationException "Handle is not initialized." It is a vestigial helper (BCL-origin) for an uninitialized native/OS handle scenario. In this Avalonia codebase it has no active call site; the Pooled collections never reference a handle that could be uninitialized, so it is unused dead code.

Source

Thrown at src/Avalonia.Base/Collections/Pooled/ThrowHelper.cs:330

            throw new InvalidOperationException("Invalid enumerator state: enumeration cannot proceed.");
        }

        [DoesNotReturn]
        internal static void ThrowInvalidOperationException_InvalidOperation_NoValue()
        {
            throw new InvalidOperationException("No value provided.");
        }

        [DoesNotReturn]
        internal static void ThrowInvalidOperationException_ConcurrentOperationsNotSupported()
        {
            throw new InvalidOperationException("Concurrent operations are not supported.");
        }

        [DoesNotReturn]
        internal static void ThrowInvalidOperationException_HandleIsNotInitialized()
        {
            throw new InvalidOperationException("Handle is not initialized.");
        }

        [DoesNotReturn]
        internal static void ThrowFormatException_BadFormatSpecifier()
        {
            throw new FormatException("Bad format specifier.");
        }

        private static ArgumentException GetArgumentException(ExceptionResource resource)
        {
            return new ArgumentException(GetResourceString(resource));
        }

        private static InvalidOperationException GetInvalidOperationException(ExceptionResource resource)
        {
            return new InvalidOperationException(GetResourceString(resource));
        }

View on GitHub (pinned to 11c5427268)

Solutions

1. Unreachable via public APIs — confirm there is no internal/forked caller.
2. If you maintain a caller, ensure the handle/resource is initialized before use.
3. Treat an unexpected occurrence as a signal to inspect the call stack.

// Unreachable via public collection APIs. If you maintain a handle-based caller,
// ensure the handle is initialized before use.

When it happens

Trigger: Not reachable through public Avalonia collection APIs — no method calls this helper. Would only be hit from a custom/internal caller that a fork wires up.

Common situations: Appearance implies a fork or custom caller; otherwise it is unreachable. The PooledList/PooledStack APIs do not deal in handles.

Related errors

• Overlap alignment mismatch.
• Enumeration has not started.
• Enumeration has ended.
• No value provided.
• Concurrent operations are not supported.

AI-assisted analysis of AvaloniaUI/Avalonia@11c5427268 (2026-08-13). Data as JSON: /api/errors/0811ba937939a875. Report an issue: GitHub.