using System.ComponentModel.DataAnnotations; namespace OfflineDemo.Models; public class UploadModel { [Required] [StringLength(100, ErrorMessage = "Title must be less than 100 characters.")] public string Title { get; set; } = ""; [Required] [StringLength(500, ErrorMessage = "Description must be less than 500 characters.")] public string Description { get; set; } = ""; [StringLength(200, ErrorMessage = "Hashtags must be less than 200 characters.")] public string Hashtags { get; set; } = "#"; }