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                string listName = System.Web.HttpContext.Current.Request.Form["listName"];
                int listItemId = Convert.ToInt32(System.Web.HttpContext.Current.Request.Form["listItemId"]);
                string fileName = System.Web.HttpContext.Current.Request.Form["fileTitle"];
                fileName = DateTime.Now.ToString("yyyy-dd-hh-mm-ss") + "-" + fileName;
                HttpFileCollection fileCollection = System.Web.HttpContext.Current.Request.Files;
                if (fileCollection.Count > 0)
                {
                    SPList list = web.Lists[listName];
                    for (int i = 0; i < fileCollection.Count; i++)
                    {
                        HttpPostedFile file = fileCollection[i];
                        var filePath = ProcessUploadFile(file); //这个应该是本地路径
                        SPListItem item = list.GetItemById(listItemId);
                        byte[] bytes = System.IO.File.ReadAllBytes(filePath);
                        site.AllowUnsafeUpdates = true;
                        web.AllowUnsafeUpdates = true;
                        // Add the file to the ListItem as an Attachment
                        SPAttachmentCollection attachments = item.Attachments; 
                        var fileType = filePath.Substring(filePath.LastIndexOf("."));
                        fileName += fileType;
                        attachments.Add(fileName, bytes);
                        item.Update();
                        site.AllowUnsafeUpdates = false;
                        web.AllowUnsafeUpdates = false;
                    }
                    jsonData = JsonConvert.SerializeObject(new { result = true });
                }else
                {
                    jsonData = JsonConvert.SerializeObject(new { result = false, error = "没有文件上传" });
                }

 using System;
        using System.Collections.Generic;
        using System.Linq;
        using System.Web;
        using System.IO;
        using System.Net;
        using FileOperationAboutSharePoint.SPCopyService;
         
        namespace FileOperationAboutSharePoint.FileOperation
        {
            public class SPServiceOperation : IFileOperation
            {
                public bool UploadFileToSPSite(string domain, string userAccount, string pwd, string documentLibraryUrl, string localFilePath, ref string statusInfo)
                {
                    bool isSuccess = false;
                    try
                    {
                        string fileName = Path.GetFileName(localFilePath);
                        string tempFilePath = string.Format("{0}{1}", Path.GetTempPath(), fileName);
                        File.Copy(localFilePath, tempFilePath, true);
                        FileStream fs = new FileStream(tempFilePath, FileMode.Open, FileAccess.Read);
                        BinaryReader br = new BinaryReader(fs);
                        byte[] fileContent = br.ReadBytes((int)fs.Length);
                        br.Close();
                        fs.Close();
                        Copy service = CreateCopy(domain, userAccount, pwd);
                        service.Timeout = System.Threading.Timeout.Infinite;
                        FieldInformation fieldInfo = new FieldInformation();
                        FieldInformation[] fieldInfoArr = { fieldInfo };
                        CopyResult[] resultArr;
                        service.CopyIntoItems(
                            tempFilePath,
                            new string[] { string.Format("{0}{1}", documentLibraryUrl, fileName) },
                            fieldInfoArr,
                            fileContent,
                            out resultArr);
                        isSuccess = resultArr[0].ErrorCode == CopyErrorCode.Success;
                        if (!isSuccess)
                        {
                            statusInfo = string.Format("Failed Info: {0}", resultArr[0].ErrorMessage);
                        }
         
                    }
                    catch (Exception ex)
                    {
                        statusInfo = string.Format("Failed Info: {0}", ex.Message);
                        isSuccess = false;
                    }
                    return isSuccess;
                }
         
                public bool DownloadFileFromSPSite(string domain, string userAccount, string pwd, string documentUrl, string localFilePath, ref string statusInfo)
                {
                    bool isSuccess = false;
                    try
                    {
                        Copy service = CreateCopy(domain, userAccount, pwd);
                        service.Timeout = System.Threading.Timeout.Infinite;
                        FieldInformation[] fieldInfoArr;
                        byte[] fileContent;
                        service.GetItem(documentUrl,out fieldInfoArr,out fileContent);
                        if (fileContent != null)
                        {
                            FileStream fs = new FileStream(localFilePath, FileMode.Create, FileAccess.Write);
                            fs.Write(fileContent, 0, fileContent.Length);
                            fs.Close();
                            isSuccess = true;
                        }
                        else
                        {
                            statusInfo = string.Format("Failed Info: {0}不存在", documentUrl);
                            isSuccess = false;
                        }
                    }
                    catch (Exception ex)
                    {
                        statusInfo = string.Format("Failed Info: {0}", ex.Message);
                        isSuccess = false;
                    }
                    return isSuccess;
                }
         
                private Copy CreateCopy(string domain, string userAccount, string pwd)
                {
                    Copy service = new Copy();
                    if (String.IsNullOrEmpty(userAccount))
                    {
                        service.UseDefaultCredentials = true;
                    }
                    else
                    {
                        service.Credentials = new NetworkCredential(userAccount, pwd, domain);
                    }
                    return service;
                }
            }
        }