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RuleContext

Provides access to dependency rule results during execution. Used with DependsOnRuleId.

public class RuleContext

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Methods

GetResult(Guid)

Gets the RuleResult for a specific rule ID. Returns RuleResult? (null if the rule has not executed yet).

RuleResult? dependencyResult = context.GetResult(validateCustomer.Id);
if (dependencyResult is { Success: true })
{
    // dependency executed and passed
}

GetValue<T>(Guid)

Gets the typed Value from a rule’s result.

int taxAmount = context.GetValue<int>(taxRule.Id);

⚠️ Caution: Returns default(T) when rule not found — ambiguous for value types.

TryGetValue<T>(Guid, out T)

Safer alternative that distinguishes “not found” from “value was default”.

if (context.TryGetValue<int>(taxRule.Id, out var amount))
{
    Console.WriteLine($"Tax: {amount}");
}
else
{
    Console.WriteLine("Tax rule not found or failed");
}

StoreResult(Guid, RuleResult)

Stores a result (called internally by the execution engine).

context.StoreResult(rule.Id, result);

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Usage with DependsOnRuleId

RuleContext is a host-side API. There is no context variable in scope inside an Expression or Action string — those strings may only reference declared RuleParameters. The host code reads dependency results from the context after (or between) rule execution.

var taxRule = new Rule
{
    Description = "Calculate tax",
    // Expressions/actions reference declared parameters only — never "context".
    Action = "customer.TaxAmount = customer.Amount * 0.08m"
};

var totalRule = new Rule
{
    Description = "Calculate total",
    DependsOnRuleId = taxRule.Id,
    Action = "customer.Total = customer.Amount + customer.TaxAmount"
};

// Host code inspects dependency results via RuleContext.
var context = new RuleContext();
// ... engine stores each rule's result into the context as it runs ...

if (context.TryGetValue<decimal>(taxRule.Id, out var tax))
{
    Console.WriteLine($"Tax computed by dependency: {tax}");
}

RuleResult? taxResult = context.GetResult(taxRule.Id);
if (taxResult is { Success: true })
{
    // proceed knowing the tax rule succeeded
}

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Related

• Rule.DependsOnRuleId — Dependency declaration
• Rule.ExecuteWithContext — Execution with context