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Lifecycle Events

Attach event handlers to rules for custom logic before and after execution.

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OnRuleExecuting

Fires before a rule evaluates. Set Cancel = true to skip.

rule.OnRuleExecuting += (sender, args) =>
{
    Console.WriteLine($"About to execute: {args.Rule.Description}");
    
    if (args.Parameters[0].Value is Customer c && c.Name == "SkipMe")
    {
        args.Cancel = true;
        args.CancelReason = "Customer opted out";
    }
};

When cancelled:

• Rule returns Success = true (skipped, not failed)
• OnRuleExecuted still fires with cancellation info
• CancelReason embedded as OperationCanceledException

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OnRuleExecuted

Fires after a rule completes — success, failure, or cancellation.

rule.OnRuleExecuted += (sender, args) =>
{
    Console.WriteLine($"Rule {args.Rule.Description}: {(args.Result.Success ? "PASS" : "FAIL")}");
    Console.WriteLine($"Elapsed: {args.Elapsed.TotalMilliseconds}ms");
    
    if (args.Exception != null)
        Console.WriteLine($"Exception: {args.Exception.Message}");
};

Event args:

• args.Rule — The rule that executed
• args.Result — Full RuleResult
• args.Elapsed — Execution time
• args.Exception — Exception if failed

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Use Cases

Use Case	Handler
Audit logging	OnRuleExecuted — write to audit table
Circuit breaker	OnRuleExecuting — cancel if unhealthy
Metrics	OnRuleExecuted — record timing
Feature flags	OnRuleExecuting — conditional skip
Debugging	Both — trace evaluation flow

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Child Rule Events

Child rules fire their own events independently.

child.OnRuleExecuting += (s, e) => { /* fires when child evaluates */ };
parent.OnRuleExecuting += (s, e) => { /* fires when parent evaluates */ };

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Related

• Rule — Event properties