如果是ienumerable< httppostedfilebase>传递null错误。

本文介绍了如果是ienumerable&lt; httppostedfilebase&gt;传递null错误。的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我正在研究mvc 5项目，视图页面内有3个输入类型文件上传器。 这里如果我选择的只有一个fileUploader，另外两个正在传递null。如果null存在，我想避免保存。通过使用下面的代码，我该如何解决这个问题？ 错误：对象引用没有设置为对象的实例。 请找到下面的图片，显示错误原因。 [ ^ ] 我的尝试： [HttpPost] public ActionResult PremiumUserRegistration（IEnumerable< HttpPostedFileBase> fileUpload） { IList< HttpPostedFileBase> ; list =（IList< HttpPostedFileBase>）fileUpload; HttpFileCollectionBase files = Request.Files; var httpPostedFile = HttpContext.Request.Files [ 0 ]; if （httpPostedFile.ContentLength！= 0 ） { for （ int i = 0 ; i < fileUpload.C​​ount（）; i ++） { if （list [i] .ContentLength > 0 && i == 0 ） { HttpPostedFileBase file = files [i]; LogoImage = Path.GetFileName（partnersVM.listPartnerVM.PartnerName + _ + list [ I] .FileName）; var path = Path.Combine（Server.MapPath（ 〜/ UploadedImages / PremiUserRegistration / LogoImage /），LogoImage）; file.SaveAs（path）; } else if （list [i] .ContentLength > 0 && i == 1 ） { HttpPostedFileBase file = files [i]; TitlePictureImage = Path.GetFileName（partnersVM.listPartnerVM.PartnerName + _ + list [ I] .FileName）; var path = Path.Combine（Server.MapPath（ 〜/ UploadedImages / PremiUserRegistration / TitlePicture /），TitlePictureImage）; file.SaveAs（path）; } else if （list [i] .ContentLength > 0 && i == 2 ） { HttpPostedFileBase file = files [i]; TitlePictureImage = Path.GetFileName（partnersVM.listPartnerVM.PartnerName + _ + list [ I] .FileName）; var path = Path.Combine（Server.MapPath（ 〜/ UploadedImages / PremiUserRegistration / Brochure /），TitlePictureImage）; file.SaveAs（path）; } } } } 请帮助我... 解决方案 添加此行以验证 null value for（int i = 0; i< fileUpload.C​​ount（）; i ++） { if（List [i]！= null ） { if（list [i] .ContentLength> 0&& i == 0） { HttpPostedFileBase file =文件[I]; LogoImage = Path.GetFileName（partnersVM.listPartnerVM.PartnerName +_+ list [i] .FileName）; var path = Path.Combine（Server.MapPath（〜/ UploadedImages / PremiUserRegistration / LogoImage /），LogoImage）; file.SaveAs（path）; } else if（list [i] .ContentLength> 0&& i == 1） { HttpPostedFileBase file = files [i]; TitlePictureImage = Path.GetFileName（partnersVM.listPartnerVM.PartnerName +_+ list [i] .FileName）; var path = Path.Combine（Server.MapPath（〜/ UploadedImages / PremiUserRegistration / TitlePicture /），TitlePictureImage）; file.SaveAs（path）; } else if（list [i] .ContentLength> 0&& i == 2） { HttpPostedFileBase file = files [i]; TitlePictureImage = Path.GetFileName（partnersVM.listPartnerVM.PartnerName +_+ list [i] .FileName）; var path = Path.Combine（Server.MapPath（〜/ UploadedImages / PremiUserRegistration / Brochure /），TitlePictureImage）; file.SaveAs（path）; } } } I am working on mvc 5 project, there is 3 input type file uploader inside view page.Here if I am selecting the only one fileUploader, another two are passing null. I want to avoid to save if null existing. By using below code, how can I solve that issue?error: "Object reference not set to an instance of an object."please find the below image, that showing error cause.[^]What I have tried:[HttpPost] public ActionResult PremiumUserRegistration(IEnumerable<HttpPostedFileBase> fileUpload) { IList<HttpPostedFileBase> list = (IList<HttpPostedFileBase>)fileUpload; HttpFileCollectionBase files = Request.Files; var httpPostedFile = HttpContext.Request.Files[0]; if (httpPostedFile.ContentLength != 0) { for (int i = 0; i < fileUpload.Count(); i++) { if (list[i].ContentLength > 0 && i == 0) { HttpPostedFileBase file = files[i]; LogoImage = Path.GetFileName(partnersVM.listPartnerVM.PartnerName + "_" + list[i].FileName); var path = Path.Combine(Server.MapPath("~/UploadedImages/PremiUserRegistration/LogoImage/"), LogoImage); file.SaveAs(path); } else if (list[i].ContentLength > 0 && i == 1) { HttpPostedFileBase file = files[i]; TitlePictureImage = Path.GetFileName(partnersVM.listPartnerVM.PartnerName + "_" + list[i].FileName); var path = Path.Combine(Server.MapPath("~/UploadedImages/PremiUserRegistration/TitlePicture/"), TitlePictureImage); file.SaveAs(path); } else if (list[i].ContentLength > 0 && i == 2) { HttpPostedFileBase file = files[i]; TitlePictureImage = Path.GetFileName(partnersVM.listPartnerVM.PartnerName + "_" + list[i].FileName); var path = Path.Combine(Server.MapPath("~/UploadedImages/PremiUserRegistration/Brochure/"), TitlePictureImage); file.SaveAs(path); } } }}Please help me... 解决方案 add this line to validate null valuefor (int i = 0; i < fileUpload.Count(); i++) { if (List[i] != null) { if (list[i].ContentLength > 0 && i == 0) { HttpPostedFileBase file = files[i]; LogoImage = Path.GetFileName(partnersVM.listPartnerVM.PartnerName + "_" + list[i].FileName); var path = Path.Combine(Server.MapPath("~/UploadedImages/PremiUserRegistration/LogoImage/"), LogoImage); file.SaveAs(path); } else if (list[i].ContentLength > 0 && i == 1) { HttpPostedFileBase file = files[i]; TitlePictureImage = Path.GetFileName(partnersVM.listPartnerVM.PartnerName + "_" + list[i].FileName); var path = Path.Combine(Server.MapPath("~/UploadedImages/PremiUserRegistration/TitlePicture/"), TitlePictureImage); file.SaveAs(path); } else if (list[i].ContentLength > 0 && i == 2) { HttpPostedFileBase file = files[i]; TitlePictureImage = Path.GetFileName(partnersVM.listPartnerVM.PartnerName + "_" + list[i].FileName); var path = Path.Combine(Server.MapPath("~/UploadedImages/PremiUserRegistration/Brochure/"), TitlePictureImage); file.SaveAs(path); } } } 这篇关于如果是ienumerable&lt; httppostedfilebase&gt;传递null错误。的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！