ASP.NET 核心 5 MVC - Session 存储在 select 元素中，带有选项

Question

I want to add Sesson Storage in my select with options. I have 4 options. And whatever the user choose, I want that choice to persist in current session, or until the user change the option again.

Here is my controller action

public IActionResult Index(string sortOrder, string filterString)
        {
            //These lines of code creates the filtering for all the types
            ViewData["TypeSortParm"] = String.IsNullOrEmpty(sortOrder) ? "types" : "";
            ViewData["CurrentFilter"] = filterString;
            var types = from t in _context.LibraryItems
                        select t;
            if (!String.IsNullOrEmpty(filterString))
            {
                types = types.Where(t => t.Type.Contains(filterString));
            }

            switch (sortOrder)
            {
                case "types":
                    types = types.OrderByDescending(s => s.Type);
                    break;
                default:
                    types = types.OrderBy(s => s.Category);
                    break;
            }

            var libs = _context.LibraryItems.Include(c => c.Category).ToList();

            var viewModel = new CatagoriesAndLibraryViewModel
            {
                Categories = _context.Categories.ToList(),
                LibraryItems = (filterString != null) ? libs.Where(x => x.Type == filterString).ToList() : libs
            };

            return View(viewModel);
        }

This adds a filter function. This section is filtering diffrent types of objects.

This is my razor page

<form asp-action="Index" method="get">
    <div>
        <p>
            Find by Type: <select type="text" name="filterString" value="@ViewData["CurrentFilter"]" class="custom-select">
                <option selected>Select a type</option>
                <option value="Book">Book</option>
                <option value="AudioBook">AudioBook</option>
                <option value="ReferenceBook">Reference Book</option>
                <option value="DVD">DVD</option>
            </select>
            <hr />
            <input type="submit" value="Filter" class="btn btn-outline-success" /> |
            <a asp-action="Index" class="btn btn-outline-dark">Back to full list</a>
        </p>
    </div>
</form>

How can I make so the users choice of type will persist during the session?

Answer 1

AddSession in ConfigureServices.

services.AddDistributedMemoryCache();
services.AddSession(options =>
{
    options.IdleTimeout = TimeSpan.FromSeconds(10);
    options.Cookie.HttpOnly = true;
    options.Cookie.IsEssential = true;
});

UseSession in Configure.

app.UseSession();

For more details, refer to the doc .