ASP.NET Core 7 MVC中实现全站生效的食谱分类筛选功能

我正在开发基于ASP.NET Core 7的食谱博客网站，希望在导航栏中实现食谱分类筛选（如全部食谱、素食食谱、非素食食谱），让该筛选能作用于全站所有页面以优化用户体验。以下是我的相关代码：

FilterController.cs:

public class FilterController : Controller
{
     private readonly ApplicationDbContext _context;

     public FilterController(ApplicationDbContext context)
     {
         _context = context;
     }

     [HttpPost]
     public async Task<IActionResult> Index(PostCategory? postCategory)
     {
         var post = from p in _context.Posts select p;

         // 分类筛选
         if (postCategory != null)
         {
             post = _context.Posts.Where(c => c.PostCategory == postCategory);
         }

         return View(await post.ToListAsync());
     }
}

_TopNavbar.cshtml:

<nav class="navbar navbar-expand navbar-toggleable-sm navbar-light bg-white border-bottom box-shadow mb-3 ps-10 fixed-top">
    <div class="container-fluid">

        <!-- 选项区 -->
        <div class="navbar-collapse collapse d-sm-inline-flex justify-content-between ps-3">

            <!-- 下拉筛选 -->
            <div class="col-4">
                <form asp-controller="Filter" asp-action="Index" id="category">
                    <select class="form-control" asp-items="@Html.GetEnumSelectList<PostCategory>()" name="postCategory" id="post-filter">
                        <option value="">全部</option>
                    </select>
                    <button class="btn btn-outline-success me-2" type="submit">筛选</button>
                    <a class="btn btn-outline-danger" asp-area="" asp-controller="Post" asp-action="Index">重置</a>
                </form>
            </div>

        </div>
    </div>
</nav>

内容的提问来源于stack exchange，提问作者ZNAXNOR