(前言:这个问题是关于2011年发布的ASP.NET MVC 3.0,而不是关于2019年发布的ASP.NETCore 3.0)
我想用asp.net mvc上传文件。如何使用html输入文件控件上载文件?
(前言:这个问题是关于2011年发布的ASP.NET MVC 3.0,而不是关于2019年发布的ASP.NETCore 3.0)
我想用asp.net mvc上传文件。如何使用html输入文件控件上载文件?
当前回答
请注意此代码仅用于上传图像。我使用HTMLHelper上传图像。在cshtml文件中放入以下代码
@using (Html.BeginForm("UploadImageAction", "Admin", FormMethod.Post, new { enctype = "multipart/form-data", id = "myUploadForm" }))
{
<div class="controls">
@Html.UploadFile("UploadImage")
</div>
<button class="button">Upload Image</button>
}
然后为Upload标记创建HTMLHelper
public static class UploadHelper
{
public static MvcHtmlString UploadFile(this HtmlHelper helper, string name, object htmlAttributes = null)
{
TagBuilder input = new TagBuilder("input");
input.Attributes.Add("type", "file");
input.Attributes.Add("id", helper.ViewData.TemplateInfo.GetFullHtmlFieldId(name));
input.Attributes.Add("name", helper.ViewData.TemplateInfo.GetFullHtmlFieldName(name));
if (htmlAttributes != null)
{
var attributes = HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes);
input.MergeAttributes(attributes);
}
return new MvcHtmlString(input.ToString());
}
}
最后在行动中上传你的文件
[AjaxOnly]
[HttpPost]
public ActionResult UploadImageAction(HttpPostedFileBase UploadImage)
{
string path = Server.MapPath("~") + "Files\\UploadImages\\" + UploadImage.FileName;
System.Drawing.Image img = new Bitmap(UploadImage.InputStream);
img.Save(path);
return View();
}
其他回答
使用formdata上载文件
.cshtml文件
var files = $("#file").get(0).files;
if (files.length > 0) {
data.append("filekey", files[0]);}
$.ajax({
url: '@Url.Action("ActionName", "ControllerName")', type: "POST", processData: false,
data: data, dataType: 'json',
contentType: false,
success: function (data) {
var response=data.JsonData;
},
error: function (er) { }
});
服务器端代码
if (System.Web.HttpContext.Current.Request.Files.AllKeys.Any())
{
var pic = System.Web.HttpContext.Current.Request.Files["filekey"];
HttpPostedFileBase filebase = new HttpPostedFileWrapper(pic);
var fileName = Path.GetFileName(filebase.FileName);
string fileExtension = System.IO.Path.GetExtension(fileName);
if (fileExtension == ".xls" || fileExtension == ".xlsx")
{
string FileName = Guid.NewGuid().GetHashCode().ToString("x");
string dirLocation = Server.MapPath("~/Content/PacketExcel/");
if (!Directory.Exists(dirLocation))
{
Directory.CreateDirectory(dirLocation);
}
string fileLocation = Server.MapPath("~/Content/PacketExcel/") + FileName + fileExtension;
filebase.SaveAs(fileLocation);
}
}
保存多个文件的简单方法
cshtml
@using (Html.BeginForm("Index","Home",FormMethod.Post,new { enctype = "multipart/form-data" }))
{
<label for="file">Upload Files:</label>
<input type="file" multiple name="files" id="files" /><br><br>
<input type="submit" value="Upload Files" />
<br><br>
@ViewBag.Message
}
控制器
[HttpPost]
public ActionResult Index(HttpPostedFileBase[] files)
{
foreach (HttpPostedFileBase file in files)
{
if (file != null && file.ContentLength > 0)
try
{
string path = Path.Combine(Server.MapPath("~/Files"), Path.GetFileName(file.FileName));
file.SaveAs(path);
ViewBag.Message = "File uploaded successfully";
}
catch (Exception ex)
{
ViewBag.Message = "ERROR:" + ex.Message.ToString();
}
else
{
ViewBag.Message = "You have not specified a file.";
}
}
return View();
}
我在做文件上传概念时也遇到过同样的错误。我知道开发人员为这个问题提供了很多答案。
尽管我回答这个问题的原因是,由于下面提到的疏忽错误,我犯了这个错误。
<input type="file" name="uploadedFile" />
在指定name属性时,请确保控制器参数也具有相同的名称值“uploadedFile”。这样地:
[HttpPost]
public ActionResult FileUpload(HttpPostedFileBase uploadedFile)
{
}
否则它不会被映射。
通常,您还希望传递一个视图模型,而不仅仅是一个文件。在下面的代码中,您将发现一些其他有用的功能:
检查文件是否已附加检查文件大小是否为0检查文件大小是否大于4 MB检查文件大小是否小于100字节检查文件扩展名
可以通过以下代码完成:
[HttpPost]
public ActionResult Index(MyViewModel viewModel)
{
// if file's content length is zero or no files submitted
if (Request.Files.Count != 1 || Request.Files[0].ContentLength == 0)
{
ModelState.AddModelError("uploadError", "File's length is zero, or no files found");
return View(viewModel);
}
// check the file size (max 4 Mb)
if (Request.Files[0].ContentLength > 1024 * 1024 * 4)
{
ModelState.AddModelError("uploadError", "File size can't exceed 4 MB");
return View(viewModel);
}
// check the file size (min 100 bytes)
if (Request.Files[0].ContentLength < 100)
{
ModelState.AddModelError("uploadError", "File size is too small");
return View(viewModel);
}
// check file extension
string extension = Path.GetExtension(Request.Files[0].FileName).ToLower();
if (extension != ".pdf" && extension != ".doc" && extension != ".docx" && extension != ".rtf" && extension != ".txt")
{
ModelState.AddModelError("uploadError", "Supported file extensions: pdf, doc, docx, rtf, txt");
return View(viewModel);
}
// extract only the filename
var fileName = Path.GetFileName(Request.Files[0].FileName);
// store the file inside ~/App_Data/uploads folder
var path = Path.Combine(Server.MapPath("~/App_Data/uploads"), fileName);
try
{
if (System.IO.File.Exists(path))
System.IO.File.Delete(path);
Request.Files[0].SaveAs(path);
}
catch (Exception)
{
ModelState.AddModelError("uploadError", "Can't save file to disk");
}
if(ModelState.IsValid)
{
// put your logic here
return View("Success");
}
return View(viewModel);
}
确保你有
@Html.ValidationMessage("uploadError")
在您的视图中查看验证错误。
还要记住,默认最大请求长度为4MB(maxRequestLength=4096),要上载更大的文件,必须在web.config中更改此参数:
<system.web>
<httpRuntime maxRequestLength="40960" executionTimeout="1100" />
(此处40960=40 MB)。
执行超时是秒的整数。您可能希望将其更改为允许上传大量文件。
另一种传输到字节[]的方法(用于保存到DB)。
@Arthur的方法工作得很好,但不能完美复制,因此MS Office文档在从数据库检索后可能无法打开。MemoryStream.GetBuffer()可以在字节[]的末尾返回额外的空字节,但可以使用MemoryStream.ToArray()来解决这个问题。然而,我发现这个替代方案可以完美地适用于所有文件类型:
using (var binaryReader = new BinaryReader(file.InputStream))
{
byte[] array = binaryReader.ReadBytes(file.ContentLength);
}
这是我的完整代码:
文档类别:
public class Document
{
public int? DocumentID { get; set; }
public string FileName { get; set; }
public byte[] Data { get; set; }
public string ContentType { get; set; }
public int? ContentLength { get; set; }
public Document()
{
DocumentID = 0;
FileName = "New File";
Data = new byte[] { };
ContentType = "";
ContentLength = 0;
}
}
文件下载:
[HttpGet]
public ActionResult GetDocument(int? documentID)
{
// Get document from database
var doc = dataLayer.GetDocument(documentID);
// Convert to ContentDisposition
var cd = new System.Net.Mime.ContentDisposition
{
FileName = doc.FileName,
// Prompt the user for downloading; set to true if you want
// the browser to try to show the file 'inline' (display in-browser
// without prompting to download file). Set to false if you
// want to always prompt them to download the file.
Inline = true,
};
Response.AppendHeader("Content-Disposition", cd.ToString());
// View document
return File(doc.Data, doc.ContentType);
}
文件上载:
[HttpPost]
public ActionResult GetDocument(HttpPostedFileBase file)
{
// Verify that the user selected a file
if (file != null && file.ContentLength > 0)
{
// Get file info
var fileName = Path.GetFileName(file.FileName);
var contentLength = file.ContentLength;
var contentType = file.ContentType;
// Get file data
byte[] data = new byte[] { };
using (var binaryReader = new BinaryReader(file.InputStream))
{
data = binaryReader.ReadBytes(file.ContentLength);
}
// Save to database
Document doc = new Document()
{
FileName = fileName,
Data = data,
ContentType = contentType,
ContentLength = contentLength,
};
dataLayer.SaveDocument(doc);
// Show success ...
return RedirectToAction("Index");
}
else
{
// Show error ...
return View("Foo");
}
}
视图(代码段):
@using (Html.BeginForm("GetDocument", "Home", FormMethod.Post, new { enctype = "multipart/form-data" }))
{
<input type="file" name="file" />
<input type="submit" value="Upload File" />
}