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=" 180px; text-align: right;"><%=Resources.WebResource.OE_ID_TYPE%>
      <!--ID Type-->
      :
  </td>
  <td style="color: #F90;">                                                 
      <asp:DropDownList ID="drpIDType_N" runat="server" style=" 25%;" OnSelectedIndexChanged="drpIDType_N_SelectedIndexChanged" AutoPostBack="true"></asp:DropDownList>
      <span style="color: Red;">*</span>
      <asp:FileUpload ID="btnFile" runat="server" Style=" 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="15%"><%=Resources.WebResource.IMG_PREVIEW%></a>       
  </td>
</tr>
<tr>
  <td class="subject" nowrap="nowrap" align="right" style=" 180px; text-align: right;"><%=Resources.WebResource.OE_ID_NO%>
      <!--ID No-->
      :
  </td>
  <td class="name">
      <input type="text" runat="server" id="txtIDNO_N" maxlength="50" style=" 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 = 0; 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 > 0)
    {
        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, 850, 630, "newwin");
    }
    else if ((/Trident/7./).test(navigator.userAgent))//IE11浏览器
    {
        var strParm = s_EmployeeID + "," + s_DEPID
        openNewWin_IE11(strUrl, strParm, 850, 630, "newwin");
    }
    else//其他浏览器
    {
        var aryParm = [["EmployeeID", s_EmployeeID], ["DEPID", s_DEPID]];
        OpenNewWin(strUrl, aryParm, 850, 630, "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="UploadTMPaaa.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[0] == null ? "" : arrParm[0];
            _DepID = arrParm[1] == null ? "" : arrParm[1];
        }
        
        //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 > 0 && dtImg.Rows[0]["ImgFile"] != DBNull.Value)
        {
            if (Directory.Exists(Server.MapPath(strPhotoPath)) == false)
            {
                Directory.CreateDirectory(Server.MapPath(strPhotoPath));
            }
            string setImgResult = setImg((byte[])dtImg.Rows[0]["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=0;
    var left=0; 
    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)/2;
        left=(screen.availWidth-width)/2;
    }
    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=0;
    for(i=0;i<aryParms.length;i++)
    {
        //var aryParaTemp = aryParm[i].split("=");//每一個參數
        var aryParaTemp = aryParms[i];
        html += "<input type='hidden' name='" + aryParaTemp[0] + "' value='" + aryParaTemp[1] + "'/>";//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=0;
    var left=0; 
    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)/2;
        left=(screen.availWidth-width)/2;
    }
   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：