Pdf Türünde Dosya Kontrolü İçin Attribute

public class IsPdfFileAttribute : ValidationAttribute
    {
        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
            try
            {
                if (value != null)
                {
                    var files = (List<IFormFile>)value;
                    if (files.Count > 0)
                    {
                        var areAllFilesZip = true;
                        foreach (var file in files)
                        {
                            if (file.FileName.EndsWith(".pdf") && file.ContentType == "application/pdf"
                                )
                            {
                                using (var ms = new MemoryStream())
                                {
                                    file.CopyTo(ms);
                                    var byteArray = ms.ToArray();
                                    var content = System.Text.Encoding.UTF8.GetString(byteArray);
                                    if (Regex.IsMatch(content, @"<script|<html|<head|<title|<body|<pre|<table|<a\s+href|<img|<plaintext|<cross\-domain\-policy",
               RegexOptions.IgnoreCase | RegexOptions.CultureInvariant | RegexOptions.Multiline))
                                    {
                                        areAllFilesZip = false;
                                        break;
                                    }

                                    if (!content.StartsWith("%PDF"))
                                    {
                                        areAllFilesZip = false;
                                        break;
                                    }
                                }
                            }
                            else
                            {
                                areAllFilesZip = false;
                                break;
                            }
                        }
                        if (areAllFilesZip)
                            return ValidationResult.Success;
                    }
                }
            }
            catch (Exception ex)
            {

            }
            return new ValidationResult("Sadece PDF dosya yükleyebilirsiniz!");
        }
    } 

---

public class SampleModel
    {
        [IsPdfFile]
        public List<IFormFile> SamplePdfFile { get; set; }
    }

---

// HomeController.cs

   public class HomeController : Controller
    {
        public IActionResult Index()
        {
            return View();
        }

        [HttpPost]
        [Consumes("multipart/form-data")]
        public IActionResult Index([FromForm] SampleModel model)
        {
            return View(model);
        }

    } 

---

//Index.cshtml

@{
    @model WebApplication1.Models.SampleModel
}

@using (Html.BeginForm("Index", "Home", FormMethod.Post, new { enctype = "multipart/form-data" }))
{
    <input type="file" name="SamplePdfFile" accept="application/pdf" required>
    <input type="submit" />
    if (!Html.ViewData.ModelState.IsValid)
    {
        <hr />
        <div  asp-validation-summary="All"></div>
    }
}