I have a class with a parameterless constructor and I am wondering how to get a value from the session. I have tried dependency injection but since I am using this class for deserialization, the httpcontextaccessor is always null.

public class Category
{
    public Category()
    {
        _language = "french"; <-- how to get value from session
    }

    private string _Name;
    public string Name { 
        get {
                if (!string.IsNullOrEmpty(_language))
                {
                    var dict = new Dictionary<string, string>();
                    this.localization.FirstOrDefault(x => x.TryGetValue(_language, out dict));
                    return dict != null && dict.ContainsKey("name") ? dict["name"] : _Name;
                }
                else
                    return _Name;
        }
        set
        {
            _Name = value;
        }
    }

    public List<Dictionary<string, Dictionary<string, string>>> localization { get; set; }
}

CodePudding user response：

You can get session value in custom model like below:

public class Category
{
    private readonly ISession _session;    //add this..
    public Category(ISession session)
    {
        _session = session;
        _language = _session.GetString("language");
    }

    private string? _language;
    private string _Name;
    public string Name { 
        get {
                if (!string.IsNullOrEmpty(_language))
                {
                    var dict = new Dictionary<string, string>();
                    this.localization.FirstOrDefault(x => x.TryGetValue(_language, out dict));
                    return dict != null && dict.ContainsKey("name") ? dict["name"] : _Name;
                }
                else
                    return _Name;
        }
        set
        {
            _Name = value;
        }
    }

    public List<Dictionary<string, Dictionary<string, string>>> localization { get; set; }

}

Test it in Controller:

public IActionResult Index()
{
    HttpContext.Session.SetString("language", "en-US");
    var model = new CategoryModel(HttpContext.Session);

    return View();
}

Be sure add AddSession and UseSession middleware in Program.cs or in Startup.cs.

Reference: Configure session state

but since I am using this class for deserialization, the httpcontextaccessor is always null.

A simple demo you could follow:

Model:

public class CategoryModel
{
    private readonly IHttpContextAccessor _contextAccessor;
    public CategoryModel(IHttpContextAccessor contextAccessor)
    {
        _contextAccessor = contextAccessor;
        _language = contextAccessor.HttpContext.Session.GetString("language");
    }
    //........
}

Test in Controller:

public class HomeController : Controller
{
    private readonly IHttpContextAccessor _contextAccessor;

    public HomeController(IHttpContextAccessor contextAccessor)
    {
        _contextAccessor = contextAccessor;
    }

    public IActionResult Index()
    {
        HttpContext.Session.SetString("language", "en-US");
        var model = new CategoryModel(_contextAccessor);

        return View();
    }
}

Register the service like:

//.....
builder.Services.AddSession();
builder.Services.AddHttpContextAccessor();

var app = builder.Build();

if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Home/Error");
    app.UseHsts();
}
app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseSession();
app.UseRouting();

app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");

app.Run();

CodePudding user response：

So I created a static class:

public static class AppContext
{
    public static IHttpContextAccessor HttpContextAccessor { get; set; }
    public static void Configure(IHttpContextAccessor accessor)
    {
        HttpContextAccessor = accessor;
    }
}

And then in the class where I couldn't do dependency injection, I was able to get the session:

    public Category()
    {
        _language = AppContext.HttpContextAccessor.HttpContext.Session.GetString("language");
    }

Had to add this to Configure in Startup:

AppContext.Configure(context);