客戶端：

        <asp:FileUpload ID="fuPhoto" onchange="javascript:__doPostBack('lbUploadPhoto','')" 
                                        runat="server" ToolTip="選擇圖片" /> 
        <asp:LinkButton ID="lbUploadPhoto" runat="server" OnClick="lbUploadPhoto_Click"></asp:LinkButton> 

後臺程式碼：

        //自動上傳事件 
               protected void lbUploadPhoto_Click(object sender, EventArgs e) 
               { 
                   fileUpload(); 
               } 
               //從控制元件上傳檔案 
               public void fileUpload() 
               { 
                   if (fuPhoto.PostedFile != null && fuPhoto.PostedFile.ContentLength > 0) 
                   { 
                       string ext = System.IO.Path.GetExtension(fuPhoto.PostedFile.FileName).ToLower(); 
                       if (ext != ".jpg" && ext != ".jepg" && ext != ".bmp" && ext != ".gif") 
                       { 
                           return; 
                       } 
                       string filename = "Image_" + DateTime.Now.ToString("yyyyMMddHHmmss") + ext; 
                       string path = "./UploadPhoto/" + filename; 
                       fuPhoto.PostedFile.SaveAs(Server.MapPath(path)); 
                       Response.Redirect("ImageCut.aspx?Picurl=" + Server.UrlEncode(path)); 
                   } 
                   else 
                   { 
                       //do some thing; 
                   } 
               }