使用EF核心填充DropdownList (来自另一个模型)

// 定义模型类
public class Category
{
    public int Id { get; set; }
    public string Name { get; set; }
}

// 定义数据库上下文类
public class ApplicationDbContext : DbContext
{
    public DbSet<Category> Categories { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer("your_connection_string");
    }
}

// 前端页面
<select id="categoryDropdown" name="categoryDropdown"></select>

// 后端代码
public ActionResult Index()
{
    using (var context = new ApplicationDbContext())
    {
        var categories = context.Categories.ToList();

        foreach (var category in categories)
        {
            var option = new TagBuilder("option");
            option.Attributes.Add("value", category.Id.ToString());
            option.InnerHtml.Append(category.Name);

            var dropdown = new TagBuilder("select");
            dropdown.Attributes.Add("id", "categoryDropdown");
            dropdown.Attributes.Add("name", "categoryDropdown");
            dropdown.InnerHtml.AppendHtml(option);

            // 将生成的下拉列表添加到视图中
            ViewBag.CategoryDropdown = dropdown;
        }

        return View();
    }
}