public enum CommentType
{
    Article,
    Video,
    Event
}

public class Comment
{
    public int Id { get; set; }
    public string CommentText { get; set; }
    public string User { get; set; }
    public int? TypeId { get; set; }
    public CommentType CommentType { get; set; }
}

public class Article
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string Slug { get; set; }
    public string Description { get; set; }
}

public class Video
{
    public int Id { get; set; }
    public string Url { get; set; }
    public string Description { get; set; }
}

public class Event
{
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTimeOffset? Start { get; set; }
    public DateTimeOffset? End { get; set; }
}

public class MyDbContext : DbContext
{
    public DbSet<Article> Articles { get; set; }
    public DbSet<Video> Videos { get; set; }
    public DbSet<Event> Events { get; set; }
    public DbSet<Comment> Comments { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder options)
        => options.UseSqlite("Data Source=polymorphic.db");
}

var articleComments = dbContext.Comments
                .Where(x => x.CommentType == CommentType.Article && x.TypeId.Value == 1);
foreach (var articleComment in articleComments)
{
    Console.WriteLine(articleComment.CommentText);
}

var article = new Article
{
    Title = "Article A",
    Slug = "article_a",
    Description = "No Description"
};
var comment = new Comment
{
    CommentText = "It's great",
    User = "Sirwan"
};
dbContext.ArticleComments.Add(new ArticleComment
{
    Article = article,
    Comment = comment
});

dbContext.SaveChanges();

var articleOne = dbContext.Articles
    .Include(article => article.ArticleComments)
    .ThenInclude(comment => comment.Comment)
    .First(article => article.Id == 1);
var article1Comments = articleOne.ArticleComments.Select(x => x.Comment);
Console.WriteLine(article1Comments.Count());

public class Comment
{
    public int Id { get; set; }
    public string CommentText { get; set; }
    public string User { get; set; }
    
    // Article
    public virtual Article Article { get; set; }
    public int? ArticleId { get; set; }
    
    // Video
    public virtual Video Video { get; set; }
    public int? VideoId { get; set; }
    
    // Event
    public virtual Event Event { get; set; }
    public int? EventId { get; set; }
}
public class Article
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string Slug { get; set; }
    public string Description { get; set; }
    public virtual ICollection<Comment> Comments { get; set; }
}

public class Video
{
    public int Id { get; set; }
    public string Url { get; set; }
    public string Description { get; set; }
    public virtual ICollection<Comment> Comments { get; set; }
}

public class Event
{
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTimeOffset? Start { get; set; }
    public DateTimeOffset? End { get; set; }
    public virtual ICollection<Comment> Comments { get; set; }
}

public class MyDbContext : DbContext
{
    public DbSet<Article> Articles { get; set; }
    public DbSet<Video> Videos { get; set; }
    public DbSet<Event> Events { get; set; }
    public DbSet<Comment> Comments { get; set; }
    protected override void OnConfiguring(DbContextOptionsBuilder options)
        => options.UseSqlite("Data Source=polymorphic.db");
}

using System.Linq;

public class CLinq
{
 public static string GetCommaSeparatedListNormal(string[] data)
 {
     string items = string.Empty;

     foreach (var item in data)
     {
         items += item + ", ";
     }

     return items.Remove(items.Length - 2, 1).Trim();
 }

 public static string GetCommaSeparatedList(string[] data)
 {
     return data.Aggregate((s1, s2) => s1 + ", " + s2);
 }
}

var names = new[] { "name1", "name2", "name3", "name4", "name5", "name6", "name7" };

using System.Linq;

public class CLinq
{
 public static int GetCountNormal()
 {
     var names = new[] { "name1", "name2", "name3", "name4", "name5", "name6", "name7" };
     var count = 0;
     foreach (var name in names)
     {
         if (name.Contains("name"))
             count += 1;
     }
     return count;
 }

 public static int GetCount()
 {
     var names = new[] { "name1", "name2", "name3", "name4", "name5", "name6", "name7" };
     return names.Count(name => name.Contains("name"));
 }
}

using System.Linq;
using System.Collections.Generic;

public class CLinq
{
 public static List<string> GetListNormal()
 {
     List<string> sampleList = new List<string>() { "A1", "A2", "P1", "P10", "B1", "B@", "J30", "P12" };
     List<string> result = new List<string>();
     foreach (var item in sampleList)
     {
         if (item.StartsWith("P"))
             result.Add(item);
     }
     return result;
 }

 public static List<string> GetList()
 {
     List<string> sampleList = new List<string>() { "A1", "A2", "P1", "P10", "B1", "B@", "J30", "P12" };
     return sampleList.Where(x => x.StartsWith("P")).ToList();
 }
}

1.کش کردن همیشه آخرین حربه می‌باشد

2.حذف View Engine‌های غیر ضروری

ViewEngines.Engines.Clear();
ViewEngines.Engines.Add(new RazorViewEngine());

ViewEngines.Engines.Clear();
ViewEngines.Engines.Add(new WebFormViewEngine());

• بلاکهای جزئی با عنوان اسپرینت
  
• ویژگیهای جزئی
  
• تیم‌های کوچک