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。

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>

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" />
}

您不使用文件输入控件。ASP.NET MVC中未使用服务器端控件。查看下面的博客文章，其中说明了如何在ASP.NET MVC中实现这一点。

因此，您将首先创建一个HTML表单，其中包含文件输入：

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

然后你会有一个控制器来处理上传：

public class HomeController : Controller
{
    // This action renders the form
    public ActionResult Index()
    {
        return View();
    }

    // This action handles the form POST and the upload
    [HttpPost]
    public ActionResult Index(HttpPostedFileBase file)
    {
        // Verify that the user selected a file
        if (file != null && file.ContentLength > 0) 
        {
            // extract only the filename
            var fileName = Path.GetFileName(file.FileName);
            // store the file inside ~/App_Data/uploads folder
            var path = Path.Combine(Server.MapPath("~/App_Data/uploads"), fileName);
            file.SaveAs(path);
        }
        // redirect back to the index action to show the form once again
        return RedirectToAction("Index");        
    }
}

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();
        }

由于我在IE浏览器中发现了上传文件的问题，我建议这样处理。

View

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

控制器

public class HomeController : Controller
{
    public ActionResult UploadFile()
    {
        return View();
    }

    [HttpPost]
    public ActionResult UploadFile(MyModal Modal)
    {
            string DocumentName = string.Empty;
            string Description = string.Empty;

            if (!String.IsNullOrEmpty(Request.Form["DocumentName"].ToString()))
                DocumentName = Request.Form["DocumentName"].ToString();
            if (!String.IsNullOrEmpty(Request.Form["Description"].ToString()))
                Description = Request.Form["Description"].ToString();

            if (!String.IsNullOrEmpty(Request.Form["FileName"].ToString()))
                UploadedDocument = Request.Form["FileName"].ToString();

            HttpFileCollectionBase files = Request.Files;

            string filePath = Server.MapPath("~/Root/Documents/");
            if (!(Directory.Exists(filePath)))
                Directory.CreateDirectory(filePath);
            for (int i = 0; i < files.Count; i++)
            {
                HttpPostedFileBase file = files[i];
                // Checking for Internet Explorer  
                if (Request.Browser.Browser.ToUpper() == "IE" || Request.Browser.Browser.ToUpper() == "INTERNETEXPLORER")
                {
                    string[] testfiles = file.FileName.Split(new char[] { '\\' });
                    fname = testfiles[testfiles.Length - 1];
                    UploadedDocument = fname;
                }
                else
                {
                    fname = file.FileName;
                    UploadedDocument = file.FileName;
                }
                file.SaveAs(fname);
                return RedirectToAction("List", "Home");
}