C# 使用FileUpload控件上传图片，将文件转换成二进制进行存储与读取

状况描述：

　　需要上传文件，但是不想要保存到实体路径下，便可以用该功能来实现。

效果图：

　　

　　点击【Upload】按钮，上传文件到数据库；

　　点击【Preview】，预览文件；

具体实现：

　　前台：

 <tr>
   <td class="subject" nowrap="nowrap" align="right" style="width: 180px; text-align: right;"><%=Resources.WebResource.OE_ID_TYPE%>
       <!--ID Type-->
       :
   </td>
   <td style="color: #F90;">
       <asp:DropDownList ID="drpIDType_N" runat="server" style="width: 25%;" OnSelectedIndexChanged="drpIDType_N_SelectedIndexChanged" AutoPostBack="true"></asp:DropDownList>
       <span style="color: Red;">*</span>
       <asp:FileUpload ID="btnFile" runat="server" Style="width: 25%;" />

       <input type="button" id="btnUpload" runat="server" value='<%$ Resources:WebResource,CC_UPLOAD%>' onserverclick="btnUpload_Click" Visible="true"  style="height:inherit; text-align: center;color: #b44c00;font-weight: 700;background-color: #ffe926;"   />
       <a href="Javascript: void(0)" id="lnkShowImg" runat="server" title="<%$ Resources:WebResource,IMG_PREVIEW_TITLE%>" visible="false" style="width:15%"><%=Resources.WebResource.IMG_PREVIEW%></a>
   </td>
 </tr>
 <tr>
   <td class="subject" nowrap="nowrap" align="right" style="width: 180px; text-align: right;"><%=Resources.WebResource.OE_ID_NO%>
       <!--ID No-->
       :
   </td>
   <td class="name">
       <input type="text" runat="server" id="txtIDNO_N" maxlength="" style="width: 96.6%;" />
       <span style="color: Red">*</span>
   </td>
 </tr>

　　后台：

 protected void btnUpload_Click(object sender, EventArgs e)
 {
     try
     {
         UploadImg(this.btnFile, this.txtEmployeeID, this.txtDEPID);
     }
     catch (Exception ex)
     {
         ShowError("W99999", "J00006", o_PopupWin, this.mLanguage);
         WriteLog(ex.ToString());
         WriteLog("Browser:" + HttpContext.Current.Request.Browser.Browser);
     }
 }

 private void UploadImg(FileUpload file, string s_EmployeeID, string s_DEPID)
 {
     //验证文件类型
     Boolean fileOK = false;
     String fileExtension;
     if (file.HasFile) //判断是否有图片上来了
     {
         fileExtension = System.IO.Path.GetExtension(file.FileName.Trim()).ToLower();//获取文件扩展名
         String[] allowedExtensions = { ".jpg", ".png", ".jpeg" }; //允许上传的文件格式
         for (int i = ; i < allowedExtensions.Length; i++)
         {
             if (fileExtension == allowedExtensions[i])
             {
                 fileOK = true;
                 break;
             }
         }
     }
     else
     {
         Response.Write("<script>alert('进行提示');</script>");
         return;
     }
     if (!fileOK)
     {
         Response.Write("<script>alert('进行提示');</script>");
         return;
     }

     #region 因浏览器兼容问题，会取不到文件完整路径，所以先将文件保存到本地
     string strFileLocalPath = Server.MapPath("../../Upload//Tmp//");
     string strFileName = strFileLocalPath + DateTime.Now.ToString("yyyyMMddHHmmss") + fileExtension;
     if (Directory.Exists(strFileLocalPath) == false)
     {
         Directory.CreateDirectory(strFileLocalPath);
     }
     if (file.PostedFile.FileName.Trim() != "")
     {
         file.PostedFile.SaveAs(strFileName);
         WriteLog("Browser:" + HttpContext.Current.Request.Browser.Browser);
     }
     #endregion

     //将文件读进二进制内存
     byte[] photo = Utility.getImg(strFileName, true);

     //插入数据库
     o_CC_Insured_BLL.insertOrUpdateCCImg(fileExtension, System.IO.Path.GetFileName(file.PostedFile.FileName), photo);

     //给【Preview】赋JS事件
     setShowImgLink(s_EmployeeID, s_DEPID);

     //提示上传成功
     ShowOk("W00058", "J00005", o_PopupWin, this.mLanguage);
 }

 /// <summary>
 /// 从数据库里面查询已上传的文件
 /// </summary>
 /// <param name="filePath"></param>
 /// <returns></returns>
 private void setShowImgLink(string s_EmployeeID, string s_DEPID)
 {
     DataTable dtimg = new DataTable();

     dtimg = o_CC_Insured_BLL.getUploadFileCC(s_EmployeeID, s_DEPID);
     if (dtimg.Rows.Count > )
     {
         lnkShowImg.Attributes.Add("onclick", "funOpenShowImage('" + s_EmployeeID + "','" + s_DEPID + "');");
         lnkShowImg.Visible = true;
     }
     else
     {
         lnkShowImg.Visible = false;
     }
 }

 /// <summary>
 /// 将图片文件写入二进制对象
 /// </summary>
 /// <param name="filePath"></param>
 /// <returns></returns>
 public static byte[] getImg(string filePath, bool deleteFlg)
 {
     //读取图片
     FileStream fs = new System.IO.FileStream(filePath, FileMode.Open, FileAccess.Read);
     BinaryReader br = new BinaryReader(fs);
     byte[] photo;
     try
     {
         photo = br.ReadBytes((int)fs.Length);
     }
     finally
     {
         br.Close();
         fs.Close();
     }
     //删除文件
     if (deleteFlg)
     {
         //删除图片文件
         if (File.Exists(filePath))
         {
             File.Delete(filePath);
         }
     }
     return photo;
 }

　　JS：

 function funOpenShowImage(s_EmployeeID, s_DEPID) {
     var strUrl = "../showUploadImg.aspx";
     if (document.all)//IE浏览器
     {
         var strParm = s_EmployeeID + "," + s_DEPID
         openNewWin_IE(strUrl, strParm, , , "newwin");
     }
     else if ((/Trident\/\./).test(navigator.userAgent))//IE11浏览器
     {
         var strParm = s_EmployeeID + "," + s_DEPID
         openNewWin_IE11(strUrl, strParm, , , "newwin");
     }
     else//其他浏览器
     {
         var aryParm = [["EmployeeID", s_EmployeeID], ["DEPID", s_DEPID]];
         OpenNewWin(strUrl, aryParm, , , "newwin");
     }
 }

　　预览需要新建一个页面：

　　新建showUploadImg.aspx

　　前台：

　　添加Img控件

 <div>
         <img runat="server" id="imgShow" src="\Upload\TMP\aaa.jpg" />
 </div>

　　后台：

 protected void Page_Load(object sender, EventArgs e)
 {
     try
     {
         clearTmp(Server.MapPath("../Upload/TMP/"));
         //setInsured();
         //saveImg();

         string _EmployeeID = string.Empty;
         string _DepID = string.Empty;
         string strParm = this.Request.Form.Get("param") == null ? "" : Server.HtmlDecode(this.Request.Form.Get("param"));
         if (string.IsNullOrEmpty(strParm))
         {
             _EmployeeID = this.Request.Form.Get("EmployeeID") == null ? "" : Server.HtmlDecode(this.Request.Form.Get("EmployeeID"));
             _DepID = this.Request.Form.Get("DEPID") == null ? "" : Server.HtmlDecode(this.Request.Form.Get("DEPID"));
         }
         else
         {
             string[] arrParm = strParm.Split(',');
             _EmployeeID = arrParm[] == null ? "" : arrParm[];
             _DepID = arrParm[] == null ? "" : arrParm[];
         }

         //从数据库读取文件
         DataTable dtImg = new DataTable();
         dtImg = o_CC_Insured_Bll.getUploadFileCC(_EmployeeID, _DepID);

         string strFileName = _EmployeeID + DateTime.Now.ToString("yyyyMMddhhmmss") + ".JPG";
         string strPhotoPath = "../Upload/TMP/";
         string strFullPhotoPath = Server.MapPath(strPhotoPath) + strFileName;
         if (dtImg.Rows.Count >  && dtImg.Rows[]["ImgFile"] != DBNull.Value)
         {
             if (Directory.Exists(Server.MapPath(strPhotoPath)) == false)
             {
                 Directory.CreateDirectory(Server.MapPath(strPhotoPath));
             }
             string setImgResult = setImg((byte[])dtImg.Rows[]["ImgFile"], strFullPhotoPath);
             if (string.IsNullOrEmpty(setImgResult))
             {
                 imgShow.Src = strPhotoPath + strFileName;
             }
         }
     }
     catch
     {
         ShowError("W99999", "J00006", o_PopupWin, this.mLanguage);
     }
 }

 /// <summary>
 /// 清空文件夹下的内容
 /// </summary>
 /// <param name="folderPath"></param>
 public static void clearTmp(string folderPath)
 {
     //判斷是否有這樣的路徑
     if (System.IO.Directory.Exists(folderPath) == true)
     {
         DirectoryInfo theFolder = new DirectoryInfo(folderPath);
         FileInfo[] fileInfo = theFolder.GetFiles();
         foreach (FileInfo NextFile in fileInfo)  //遍历文件
         {
             try
             {
                 File.Delete(NextFile.FullName);
             }
             catch { }
         }
     }
 }
 /// <summary>
 /// 读取图片文件到指定目录
 /// </summary>
 /// <param name="img"></param>
 /// <param name="filePath"></param>
 /// <returns></returns>
 public static string setImg(byte[] img, string filePath)
 {
     try
     {
         BinaryWriter bw = new BinaryWriter(File.Open(filePath, FileMode.OpenOrCreate));
         bw.Write(img);
         bw.Close();
         return "";
     }
     catch (Exception ex)
     {
         return ex.ToString();
     }
 }

　　JS开启新窗口的共用方法：

 //目的：提供開啟視窗的畫面
 //參數：strUrl-->欲開啟畫面的網址，strParms-->參數，width-->畫面的寬度，height-->畫面的高度
 //      WinName-->開啟的視窗名稱
 // xx. YYYY/MM/DD   VER     AUTHOR      COMMENTS
 //  1. 2016/08/22   1.00    Anne        Create
 function OpenNewWin(strUrl,aryParms,width,height,WinName)
 {
     var top=;
     var left=;
     if (height =='' && width==''){
         width=screen.availWidth;
         height=screen.availHeight;
     }else if (height >screen.availHeight && width>screen.availWidth){
         width=screen.availWidth;
         height=screen.availHeight;
     }else{
         top=(screen.availHeight-height)/;
         left=(screen.availWidth-width)/;
     }
     var newWindow = window.open("",WinName,'width='+width+'px,height='+height+'px,dependent,left='+left+',top='+top+',status=no,toolbar=false,menubar=no,scrollbars=yes,resizable=yes',true);
     if (!newWindow) return false;

     var html ="";
     //參數的處理
     //var aryParm=strParms.split("&");//有多少個參數
     var i=;
     for(i=;i<aryParms.length;i++)
     {
         //var aryParaTemp = aryParm[i].split("=");//每一個參數
         var aryParaTemp = aryParms[i];
         html += "<input type='hidden' name='" + aryParaTemp[] + "' value='" + aryParaTemp[] + "'/>";//參數字段
     }
     html = "<html><head></head><body><form id='formid' method='post' action='"+strUrl+"'>"+html;
     html += "</form><scr"+"ipt type='text/javascript'>document.getElementById('formid').submit()</scr"+"ipt></body></html>";
     //html += "</form><script type='text/javascript'>document.getElementById('formid').submit()</script></body></html>";
     newWindow.document.write(html);//提交post數據
 } 

 //目的：提供開啟視窗的畫面(跨域跳转的话，用OpenNewWin方法，IE浏览器不兼容，故重写一个)
 //參數：strUrl-->欲開啟畫面的網址，strParms-->參數，width-->畫面的寬度，height-->畫面的高度
 //      WinName-->開啟的視窗名稱
 function openNewWin_IE(strUrl,strParam,width,height,name)
 {
     var tempForm = document.createElement("form");
     tempForm.id="tempForm1";
     tempForm.method="post";
     tempForm.action=strUrl;
     tempForm.target=name;
     var hideInput = document.createElement("input");
     hideInput.type="hidden";
     hideInput.name= "param"
     hideInput.value= strParam;
     tempForm.appendChild(hideInput);
     tempForm.attachEvent("onsubmit",function(){funWinOpen("",width,height,name);});
     document.body.appendChild(tempForm);
     tempForm.fireEvent("onsubmit");
     tempForm.submit();
     document.body.removeChild(tempForm);
 }
 function openNewWin_IE11(strUrl,strParam,width,height,name)
 {
     var tempForm = document.createElement("form");
     tempForm.id="tempForm1";
     tempForm.method="post";
     tempForm.action=strUrl;
     tempForm.target=name;
     var hideInput = document.createElement("input");
     hideInput.type="hidden";
     hideInput.name= "param"
     hideInput.value= strParam;
     tempForm.appendChild(hideInput);
     tempForm.addEventListener("onsubmit",function(){funWinOpen("",width,height,name);});
     document.body.appendChild(tempForm);
     tempForm.submit();
     document.body.removeChild(tempForm);
 }
 function funWinOpen(strUrl,width,height,WinName)
 {
     var top=;
     var left=;
     if (height =='' && width==''){
         width=screen.availWidth;
         height=screen.availHeight;
     }else if (height >screen.availHeight && width>screen.availWidth){
         width=screen.availWidth;
         height=screen.availHeight;
     }else{
         top=(screen.availHeight-height)/;
         left=(screen.availWidth-width)/;
     }
    var newWindow = window.open(strUrl,WinName,'width='+width+'px,height='+height+'px,dependent,left='+left+',top='+top+',status=no,toolbar=false,menubar=no,scrollbars=yes,resizable=yes',true);
 }

　　预览效果图：