C#

public class User
    {
        [Key]
        public int UserId { get; set; }
        public string Name { get; set; }
        public string LastName { get; set; }
        public string? ImageUrl { get; set; }

        //Navigation properties
        public virtual List<Request> Requests { get; set; }
        public virtual List<Message> Messages { get; set; }
    }

public class Request
    {
        [Key]
        public int RequestId { get; set; }
        public DateTime RequestTime { get; set; } = DateTime.Now;
        public bool? AcceptStatus { get; set; }

        //Navigation properties
        public User TargetUserRef { get; set; }
        public User SenderUserRef { get; set; }
    }

protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Request>()
                        .HasOne(m => m.SenderUserRef)
                        .WithMany(t => t.Requests)
                        .HasForeignKey(m => m.RequestId)
                        .OnDelete(DeleteBehavior.Restrict);

            modelBuilder.Entity<Request>()
                        .HasOne(m => m.TargetUserRef)
                        .WithMany(t => t.Requests)
                        .HasForeignKey(m => m.RequestId)
                        .OnDelete(DeleteBehavior.Restrict);
        }

Quote:

Cannot create a relationship between 'User.Requests' and 'Request.TargetUserRef' because a relationship already exists between 'User.Requests' and 'Request.SenderUserRef'. Navigations can only participate in a single relationship. If you want to override an existing relationship call 'Ignore' on the navigation 'Request.TargetUserRef' first in 'OnModelCreating'.

Is it possible to highlight all rows in listbox between two index values?
If it possible how is it done?

private static void StartInstaller()
{
    try
    {
        // Start the installler
        _ = Process.Start(_localSetupFile);

        // Wait until it's started
        Process[] processes;

        do
        {
            processes = Process.GetProcessesByName(_processName);
            Thread.Sleep(1000);
        }
        while (processes.Length == 0);
    }
    catch (Win32Exception e)
    {
        // Problem here
    }
    catch (Exception e)
    {
        // Handle the error
        throw;
    }
}