Csharp

C# Skill

C# patterns for SPT mod development targeting .NET Standard 2.1 (client) and .NET 9 (server). This codebase uses C# 12 features with Unity interop, BigBrain AI framework integration, and BepInEx plugin architecture. Focus areas: state machines, reflection-based interop, thread safety, and defensive coding for game mod stability.

Quick Start

BigBrain Layer Pattern

public class LootingLayer : CustomLayer
{
    public override string GetName() => "LootingLayer";
    
    public override bool IsActive()
    {
        try
        {
            if (BotOwner?.IsDead == true) return false;
            return SAINInterop.CanBotQuest(BotOwner, BotOwner.Position, 50f);
        }
        catch (Exception ex)
        {
            BotMindPlugin.Log?.LogError($"[{BotOwner?.name ?? "Unknown"}] IsActive error: {ex.Message}");
            return false; // Fail safe
        }
    }
}

Null-Conditional Navigation

// GOOD - Defensive null handling for game objects
var health = player?.ActiveHealthController?.GetBodyPartHealth(EBodyPart.Head)?.Current ?? 0f;

// BAD - Crashes if any part is null
var health = player.ActiveHealthController.GetBodyPartHealth(EBodyPart.Head).Current;

Key Concepts

Common Patterns

Try-Catch Wrapper for Unity Callbacks

When: Any method called by Unity or BigBrain framework

public override void Update(ActionData data)
{
    try
    {
        // Implementation that may throw
        ProcessLootTarget();
    }
    catch (Exception ex)
    {
        BotMindPlugin.Log?.LogError($"Update error: {ex.Message}\n{ex.StackTrace}");
        // Return to safe state, don't propagate
    }
}

Reflection-Based Soft Dependency

When: Optional mod integration (SAIN)

private static readonly Type? _sainType;
private static readonly MethodInfo? _canBotQuestMethod;

static SAINInterop()
{
    _sainType = Type.GetType("SAIN.SAINPlugin, SAIN");
    _canBotQuestMethod = _sainType?.GetMethod("CanBotQuest", BindingFlags.Public | BindingFlags.Static);
}

See Also

• patterns
• workflows

Related Skills

• See the dotnet skill for build configuration and project setup
• See the bepinex skill for plugin lifecycle and configuration
• See the harmony skill for runtime patching
• See the xunit skill for unit testing patterns
• See the unity skill for game object and component patterns