How to Manage State in .NET Core

 In any application development, managing state effectively is crucial for maintaining data consistency and providing a seamless user experience. In .NET Core, various techniques and libraries are available for managing state, each catering to different scenarios and requirements. This article explores different state management techniques in .NET Core and provides code examples to illustrate their usage.

Built-in State Management Techniques

Session State: Session state allows storing user-specific data across multiple requests. It's useful for maintaining user authentication, shopping cart items, etc. Session state can be managed using ASP.NET Core's HttpContext.Session property.

// Setting session value
HttpContext.Session.SetString("UserName", "JohnDoe");

// Retrieving session value
var userName = HttpContext.Session.GetString("UserName");

View State: View state stores page-specific data that needs to be persisted across postbacks. It's commonly used in web forms applications. In ASP.NET Core, the view state is not directly available like in ASP.NET Web Forms, but you can achieve similar functionality using hidden fields or TempData.

// Storing data in TempData
TempData["Message"] = "Data persisted across requests.";

// Retrieving data from TempData
var message = TempData["Message"];

Client-side State Management:

Cookies: Cookies are small pieces of data stored on the client's browser. They can be used to store user preferences, session identifiers, etc. In ASP.NET Core, cookies can be managed using Response. Cookies and Request.Cookies properties.

// Setting cookie
Response.Cookies.Append("UserName", "JohnDoe");

// Retrieving cookie
var userName = Request.Cookies["UserName"];

Local Storage: Local storage is a client-side storage mechanism available in modern web browsers. It allows storing data persistently on the client side. JavaScript can be used to interact with local storage.

// Setting data in local storage
localStorage.setItem("AuthToken", "xyz123");

// Retrieving data from local storage
var authToken = localStorage.getItem("AuthToken");

Third-party State Management Libraries 

Redux.NET: Redux.NET is a predictable state container for .NET applications, inspired by Redux for JavaScript. It helps manage application state in a predictable manner, especially in large-scale applications.

// Define actions
public class IncrementCounter { }
public class DecrementCounter { }

// Define reducer
public static int CounterReducer(int state, object action)
{
    switch (action)
    {
        case IncrementCounter _:
            return state + 1;
        case DecrementCounter _:
            return state - 1;
        default:
            return state;
    }
}

Fluxor: Fluxor is a low-boilerplate Redux-like library for .NET applications. It simplifies state management by providing features like actions, reducers, and effects.

// Define actions
public class IncrementCounter { }
public class DecrementCounter { }

// Define feature state
public class CounterState
{
    public int Count { get; }

    public CounterState(int count)
    {
        Count = count;
    }
}

// Define reducer
public static class CounterReducers
{
    [ReducerMethod]
    public static CounterState ReduceIncrementCounter(CounterState state, IncrementCounter action)
    {
        return new CounterState(state.Count + 1);
    }

    [ReducerMethod]
    public static CounterState ReduceDecrementCounter(CounterState state, DecrementCounter action)
    {
        return new CounterState(state.Count - 1);
    }
}