ASP.NET Core MVC Mastery
Lesson 15 of 58 26% of course

Service Lifetimes

23 · 8 min · 5/23/2026

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Mastering Dependency Injection Lifetimes (Transient, Scoped, Singleton)

Understanding service lifetimes is the difference between a bug-free app and one that has massive data corruption in production.

1. Transient (The Disposable)

A new instance is created **Every Time** it is requested. Best for lightweight, stateless services like a logging helper or an email formatter.

2. Scoped (The Request Gateway)

A new instance is created once per **HTTP Request**. All components in that same request share the same instance. This is Mandatory for DbContexts and UserContexts.

3. Singleton (The Global Engine)

One instance is created once, and it **Never Dies** until the server restarts. Best for caching engines or global configuration handlers.

Senior Audit: Captive Dependencies

Never inject a Scoped service into a Singleton. This is a Captive Dependency—the singleton will "capture" the scoped instance and keep it alive forever, leading to catastrophic database connection leaks and data corruption. This is an immediate fail in any architect-level interview.

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ASP.NET Core MVC Mastery

On this page

1. Transient (The Disposable) 2. Scoped (The Request Gateway) 3. Singleton (The Global Engine)
1. Core Framework
Introduction to ASP.NET Core MVC
MODULE 1: INTRODUCTION & ENVIRONMENT SETUP
Microsoft Web Stack Overview Evolution of ASP.NET Environment Setup
2. View Engine
Layouts & Partial Views in Razor
MODULE 2: .NET CORE FUNDAMENTALS
Core Concepts Project Structure Startup Flow Middleware Pipeline
MODULE 3: ASP.NET CORE BASICS
Creating Project CLI Commands wwwroot & Static Files
MODULE 4: MVC FUNDAMENTALS
MVC Architecture Dependency Injection (DI) Service Lifetimes
MODULE 5: DATA PASSING TECHNIQUES
ViewData vs ViewBag TempData ViewModel Pattern
MODULE 6: ROUTING
Conventional vs Attribute Routing Custom Constraints
MODULE 7: VIEWS & UI
Razor View Engine Layouts & Sections View Components
MODULE 8: ACTION RESULTS
ViewResult JsonResult RedirectResult
MODULE 9: HTML HELPERS
Form Helpers Custom HTML Helpers
MODULE 10: TAG HELPERS
Built-in Tag Helpers Custom Tag Helpers
MODULE 11: MODEL BINDING
FromQuery vs FromRoute Complex Binding
MODULE 12: VALIDATION
Data Annotations Remote Validation Fluent Validation
MODULE 13: STATE MANAGEMENT
Cookies & Sessions TempData
MODULE 14: FILTERS & SECURITY
Action Filters Authorize Filters Anti-forgery
MODULE 15: ENTITY FRAMEWORK CORE (DEEP DIVE)
DbContext Migrations LINQ Relationships
MODULE 16: DESIGN PATTERNS
Repository Pattern Unit of Work Clean Architecture
MODULE 17: FILE HANDLING
File Upload/Download PDF/Excel Generation
MODULE 18: ADVANCED ASP.NET CORE
Request Lifecycle Bundling & Minification Deployment
MODULE 19: PERFORMANCE & BEST PRACTICES
Caching Strategies Async Programming Secure Coding
MODULE 20: RAZOR PAGES (BONUS)
Razor Pages vs MVC
MODULE 21: REAL-WORLD PROJECTS (🔥 MUST DO)
E-Commerce Web Application Employee Management System