04 01 Overview

TypeCollections Overview

TypeCollections are enhanced enums with O(1) lookups and rich behavior. They replace traditional enums with strongly-typed classes.

Key Benefits

• O(1) lookups - Source-generated dictionaries by ID and name
• No reflection - All lookup code generated at compile time
• Rich behavior - Add properties and methods to each option
• Type-safe - Compile-time validation
• Polymorphism - Use properties instead of switch statements

Quick Example

From FilterOperators.cs:

// Access via static property (generated)
var equalOp = FilterOperators.Equal;
Console.WriteLine($"   FilterOperators.Equal: {equalOp.Name}");

// Access via lookup
var greaterThan = FilterOperators.ByName("GreaterThan");
Console.WriteLine($"   FilterOperators.ByName(\"GreaterThan\"): {greaterThan.Name}");

// Iterate all options
Console.WriteLine($"   All operators: {string.Join(", ", FilterOperators.All().Select(p => p.Name))}");

// Use behavior - no switch statements needed!
// Each operator knows how to generate SQL predicates, etc.

For TypeCollections with terminal state handling, see ExecutionStatuses:

From IExecutionStatus.cs:12-27:

public interface IExecutionStatus : ITypeOption<int, ExecutionStatusBase>
{
    bool IsTerminal { get; }
    bool IsSuccess { get; }
    bool IsFailure { get; }
    bool AllowsRetry { get; }
    bool AllowsResume { get; }
    bool IsInProgress { get; }
    bool HasWarnings { get; }
}

Pattern Components

Component	Purpose
Interface (IPaymentMethod)	Contract with behavior properties
Base class (PaymentMethodBase)	Constructor parameters, get-only properties
Options (CashPayment, etc.)	Concrete implementations
Collection (PaymentMethods)	Source-generated lookups

Next Steps

• Base Classes - Defining base classes
• Concrete Options - Creating type options
• Collection Declaration - The [TypeCollection] attribute
• Generated Lookups - Using the generated code