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。

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);
}
}

检查我的解决方案

public string SaveFile(HttpPostedFileBase uploadfile, string saveInDirectory="/", List<string> acceptedExtention =null)
{
    acceptedExtention = acceptedExtention ?? new List<String>() {".png", ".Jpeg"};//optional arguments

    var extension = Path.GetExtension(uploadfile.FileName).ToLower();

    if (!acceptedExtention.Contains(extension))
    {
        throw new UserFriendlyException("Unsupported File type");
    }
    var tempPath = GenerateDocumentPath(uploadfile.FileName, saveInDirectory);
    FileHelper.DeleteIfExists(tempPath);
    uploadfile.SaveAs(tempPath);

    var fileName = Path.GetFileName(tempPath);
    return fileName;
}

private string GenerateDocumentPath(string fileName, string saveInDirectory)
{
    System.IO.Directory.CreateDirectory(Server.MapPath($"~/{saveInDirectory}"));
    return Path.Combine(Server.MapPath($"~/{saveInDirectory}"), Path.GetFileNameWithoutExtension(fileName) +"_"+ DateTime.Now.Ticks + Path.GetExtension(fileName));
}

在基本控制器中添加这些函数，以便可以在所有控制器中使用它们

检查如何使用它

SaveFile(view.PassportPicture,acceptedExtention:new List<String>() { ".png", ".Jpeg"},saveInDirectory: "content/img/PassportPicture");

下面是一个完整的例子

[HttpPost]
public async Task<JsonResult> CreateUserThenGenerateToken(CreateUserViewModel view)
{// CreateUserViewModel contain two properties of type HttpPostedFileBase  
    string passportPicture = null, profilePicture = null;
    if (view.PassportPicture != null)
    {
        passportPicture = SaveFile(view.PassportPicture,acceptedExtention:new List<String>() { ".png", ".Jpeg"},saveInDirectory: "content/img/PassportPicture");
    }
    if (view.ProfilePicture != null)
    {
        profilePicture = SaveFile(yourHttpPostedFileBase, acceptedExtention: new List<String>() { ".png", ".Jpeg" }, saveInDirectory: "content/img/ProfilePicture");
    }
    var input = view.MapTo<CreateUserInput>();
    input.PassportPicture = passportPicture;
    input.ProfilePicture = profilePicture;


    var getUserOutput = await _userAppService.CreateUserThenGenerateToken(input);
    return new AbpJsonResult(getUserOutput);
    //return Json(new AjaxResponse() { Result = getUserOutput, Success = true });

}

MemoryStream.GetBuffer() can return extra empty bytes at the end of the byte[], but you can fix that by using MemoryStream.ToArray() instead. However, I found this alternative to work perfectly for all file types:

using (var binaryReader = new BinaryReader(file.InputStream))
{
    byte[] array = binaryReader.ReadBytes(file.ContentLength);
}
Here's my full code:

Document Class:

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;
    }
}
File Download:

[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);
}
File Upload:

[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");
    }
}
View (snippet):

@using (Html.BeginForm("GetDocument", "Home", FormMethod.Post, new { enctype = "multipart/form-data" }))
{
    <input type="file" name="file" />
    <input type="submit" value="Upload File" />
}

我必须上传100kb的文件块，最后一个上传文件使用命令存储在数据库中。我希望，这会对你有所帮助。

    public HttpResponseMessage Post(AttachmentUploadForm form)
    {
        var response = new WebApiResultResponse
        {
            IsSuccess = true,
            RedirectRequired = false
        };

        var tempFilesFolder = Sanelib.Common.SystemSettings.Globals.CreateOrGetCustomPath("Temp\\" + form.FileId);

        File.WriteAllText(tempFilesFolder + "\\" + form.ChunkNumber + ".temp", form.ChunkData);

        if (form.ChunkNumber < Math.Ceiling((double)form.Size / 102400)) return Content(response);

        var folderInfo = new DirectoryInfo(tempFilesFolder);
        var totalFiles = folderInfo.GetFiles().Length;

        var sb = new StringBuilder();

        for (var i = 1; i <= totalFiles; i++)
        {
            sb.Append(File.ReadAllText(tempFilesFolder + "\\" + i + ".temp"));
        }

        var base64 = sb.ToString();
        base64 = base64.Substring(base64.IndexOf(',') + 1);
        var fileBytes = Convert.FromBase64String(base64);
        var fileStream = new FileStream(tempFilesFolder + "\\" + form.Name, FileMode.OpenOrCreate, FileAccess.ReadWrite);
        fileStream.Seek(fileStream.Length, SeekOrigin.Begin);
        fileStream.Write(fileBytes, 0, fileBytes.Length);
        fileStream.Close();

        Directory.Delete(tempFilesFolder, true);

        var md5 = MD5.Create();

        var command = Mapper.Map<AttachmentUploadForm, AddAttachment>(form);
        command.FileData = fileBytes;
        command.FileHashCode = BitConverter.ToString(md5.ComputeHash(fileBytes)).Replace("-", "");

        return ExecuteCommand(command);
    }

Javascript（Knockout Js）

define(['util', 'ajax'], function (util, ajax) {
"use strict";

var exports = {},
     ViewModel, Attachment, FileObject;

//File Upload
FileObject = function (file, parent) {
    var self = this;
    self.fileId = util.guid();
    self.name = ko.observable(file.name);
    self.type = ko.observable(file.type);
    self.size = ko.observable();
    self.fileData = null;
    self.fileSize = ko.observable(file.size / 1024 / 1024);
    self.chunks = 0;
    self.currentChunk = ko.observable();

    var reader = new FileReader();

    // Closure to capture the file information.
    reader.onload = (function (e) {
        self.fileData = e.target.result;
        self.size(self.fileData.length);
        self.chunks = Math.ceil(self.size() / 102400);
        self.sendChunk(1);
    });

    reader.readAsDataURL(file);

    self.percentComplete = ko.computed(function () {
        return self.currentChunk() * 100 / self.chunks;
    }, self);

    self.cancel = function (record) {
        parent.uploads.remove(record);
    };

    self.sendChunk = function (number) {
        var start = (number - 1) * 102400;
        var end = number * 102400;
        self.currentChunk(number);
        var form = {
            fileId: self.fileId,
            name: self.name(),
            fileType: self.type(),
            Size: self.size(),
            FileSize: self.fileSize(),
            chunkNumber: number,
            chunkData: self.fileData.slice(start, end),
            entityTypeValue: parent.entityTypeValue,
            ReferenceId: parent.detail.id,
            ReferenceName: parent.detail.name
        };

        ajax.post('Attachment', JSON.stringify(form)).done(function (response) {
            if (number < self.chunks)
                self.sendChunk(number + 1);
            if (response.id != null) {
                parent.attachments.push(new Attachment(response));
                self.cancel(response);
            }
        });
    };
};

Attachment = function (data) {
    var self = this;
    self.id = ko.observable(data.id);
    self.name = ko.observable(data.name);
    self.fileType = ko.observable(data.fileType);
    self.fileSize = ko.observable(data.fileSize);
    self.fileData = ko.observable(data.fileData);
    self.typeName = ko.observable(data.typeName);
    self.description = ko.observable(data.description).revertable();
    self.tags = ko.observable(data.tags).revertable();
    self.operationTime = ko.observable(moment(data.createdOn).format('MM-DD-YYYY HH:mm:ss'));

    self.description.subscribe(function () {
        var form = {
            Id: self.id(),
            Description: self.description(),
            Tags: self.tags()
        };

        ajax.put('attachment', JSON.stringify(form)).done(function (response) {
            self.description.commit();
            return;
        }).fail(function () {
            self.description.revert();
        });
    });

    self.tags.subscribe(function () {
        var form = {
            Id: self.id(),
            Description: self.description(),
            Tags: self.tags()
        };

        ajax.put('attachment', JSON.stringify(form)).done(function (response) {
            self.tags.commit();
            return;
        }).fail(function () {
            self.tags.revert();
        });
    });
};

ViewModel = function (data) {
    var self = this;

    // for attachment
    self.attachments = ko.observableArray([]);
    $.each(data.attachments, function (row, val) {
        self.attachments.push(new Attachment(val));
    });

    self.deleteAttachmentRecord = function (record) {
        if (!confirm("Are you sure you want to delete this record?")) return;
        ajax.del('attachment', record.id(), { async: false }).done(function () {
            self.attachments.remove(record);
            return;
        });
    };


exports.exec = function (model) {
    console.log(model);
    var viewModel = new ViewModel(model);
    ko.applyBindings(viewModel, document.getElementById('ShowAuditDiv'));
};

return exports;
});

HTML代码：

<div class="row-fluid spacer-bottom fileDragHolder">
    <div class="spacer-bottom"></div>
    <div class="legend">
        Attachments<div class="pull-right">@Html.AttachmentPicker("AC")</div>
    </div>
    <div>
        <div class="row-fluid spacer-bottom">
            <div style="overflow: auto">
                <table class="table table-bordered table-hover table-condensed" data-bind="visible: uploads().length > 0 || attachments().length > 0">
                    <thead>
                        <tr>
                            <th class=" btn btn-primary col-md-2" style="text-align: center">
                                Name
                            </th>
                            <th class="btn btn-primary col-md-1" style="text-align: center">Type</th>
                            <th class="btn btn-primary col-md-1" style="text-align: center">Size (MB)</th>
                            <th class="btn btn-primary col-md-1" style="text-align: center">Upload Time</th>
                            <th class="btn btn-primary col-md-1" style="text-align: center">Tags</th>
                            <th class="btn btn-primary col-md-6" style="text-align: center">Description</th>
                            <th class="btn btn-primary col-md-1" style="text-align: center">Delete</th>
                        </tr>
                    </thead>
                    <tbody>
                        <!-- ko foreach: attachments -->
                        <tr>
                            <td style="text-align: center" class="col-xs-2"><a href="#" data-bind="text: name,attr:{'href':'/attachment/index?id=' + id()}"></a></td>
                            <td style="text-align: center" class="col-xs-1"><span data-bind="text: fileType"></span></td>
                            <td style="text-align: center" class="col-xs-1"><span data-bind="text: fileSize"></span></td>
                            <td style="text-align: center" class="col-xs-2"><span data-bind="text: operationTime"></span></td>
                            <td style="text-align: center" class="col-xs-3"><div contenteditable="true" data-bind="editableText: tags"></div></td>
                            <td style="text-align: center" class="col-xs-4"><div contenteditable="true" data-bind="editableText: description"></div></td>
                            <td style="text-align: center" class="col-xs-1"><button class="btn btn-primary" data-bind="click:$root.deleteAttachmentRecord"><i class="icon-trash"></i></button></td>
                        </tr>
                        <!-- /ko -->
                    </tbody>
                    <tfoot data-bind="visible: uploads().length > 0">
                        <tr>
                            <th colspan="6">Files upload status</th>
                        </tr>
                        <tr>
                            <th>Name</th>
                            <th>Type</th>
                            <th>Size (MB)</th>
                            <th colspan="2">Status</th>
                            <th></th>
                        </tr>
                        <!-- ko foreach: uploads -->
                        <tr>
                            <td><span data-bind="text: name"></span></td>
                            <td><span data-bind="text: type"></span></td>
                            <td><span data-bind="text: fileSize"></span></td>
                            <td colspan="2">
                                <div class="progress">
                                    <div class="progress-bar" data-bind="style: { width: percentComplete() + '%' }"></div>
                                </div>
                            </td>
                            <td style="text-align: center"><button class="btn btn-primary" data-bind="click:cancel"><i class="icon-trash"></i></button></td>
                        </tr>
                        <!-- /ko -->
                    </tfoot>
                </table>
            </div>
            <div data-bind="visible: attachments().length == 0" class="span12" style="margin-left:0">
                <span>No Records found.</span>
            </div>
        </div>

我给你简单易懂的方法。

首先，必须在.Cshtml文件中编写以下代码。

<input name="Image" type="file" class="form-control" id="resume" />

然后在控制器中输入以下代码：

if (i > 0) {
    HttpPostedFileBase file = Request.Files["Image"];


    if (file != null && file.ContentLength > 0) {
        if (!string.IsNullOrEmpty(file.FileName)) {
            string extension = Path.GetExtension(file.FileName);

            switch ((extension.ToLower())) {
                case ".doc":
                    break;
                case ".docx":
                    break;
                case ".pdf":
                    break;
                default:
                    ViewBag.result = "Please attach file with extension .doc , .docx , .pdf";
                    return View();
            }

            if (!Directory.Exists(Server.MapPath("~") + "\\Resume\\")) {
                System.IO.Directory.CreateDirectory(Server.MapPath("~") + "\\Resume\\");
            }

            string documentpath = Server.MapPath("~") + "\\Resume\\" + i + "_" + file.FileName;
            file.SaveAs(documentpath);
            string filename = i + "_" + file.FileName;
            result = _objbalResume.UpdateResume(filename, i);
            Attachment at = new Attachment(documentpath);

            //ViewBag.result = (ans == true ? "Thanks for contacting us.We will reply as soon as possible" : "There is some problem. Please try again later.");
        }
    } else {
        ...
    }
}

为此，您必须根据您的数据库制作BAL和DAL层。