1 namespace 上传文件  2 {  3     public partial class WebForm1 : System.Web.UI.Page  4     {  5         public static string fileName = "";  6         protected void Page_Load(object sender, EventArgs e)  7         {  8             if (!IsPostBack)  9             { 10                 BindDropDownList(); 11             } 12         } 13  14         //上传文件 15         protected void Button1_Click(object sender, EventArgs e) 16         { 17             if (FileUpload1.HasFile) 18             { 19                 fileName = FileUpload1.FileName; 20                 string result = fileUpload(fileName); 21                 if (!string.IsNullOrEmpty(result)) 22                 { 23                     Page.ClientScript.RegisterClientScriptBlock(Page.ClientScript.GetType(), "myscripts", "<script>alert(\"上传成功!\");</script>"); 24                     BindDropDownList(); 25                 } 26                 else 27                 { 28                     Page.ClientScript.RegisterClientScriptBlock(Page.ClientScript.GetType(), "myscripts", "<script>alert(\"上传失败!\");</script>"); 29                 } 30             } 31         } 32  33  34         /// <summary> 35         /// 上传文件 36         /// </summary> 37         /// <param name="fileName">文件名称</param> 38         /// <returns></returns> 39         public static string fileUpload(string fileName) 40         { 41             string fileNewName = String.Empty; 42             if (fileName.Length > 0) 43             { 44                 string fileExtension = Path.GetExtension(fileName).ToLower(); 45                 if (checkFileExtension(fileExtension)) 46                 { 47                     //fileNewName = DateTime.Now.ToString("yyyyMMddhhmmss") + fileExtension; 48                     fileNewName = fileName; 49                     HttpPostedFile file = HttpContext.Current.Request.Files[0]; 50                     file.SaveAs(HttpContext.Current.Server.MapPath("File/" + fileNewName)); 51                 } 52             } 53             return fileNewName; 54         } 55  56         /// <summary> 57         /// 检查上传文件格式是否正确 58         /// </summary> 59         /// <param name="fileExtension">文件扩展名</param> 60         /// <returns></returns> 61         public static bool checkFileExtension(string fileExtension) 62         { 63             string[] extensionArr = { ".doc", ".txt", ".pdf", ".rar", ".zip", ".docx", ".doc", ".ppt", ".png", ".gif", ".jpg", ".jpeg",".exe"}; 64             for (int i = 0; i < extensionArr.Length; i++) 65             { 66                 if (fileExtension == extensionArr[i]) 67                 { 68                     return true; 69                 } 70             } 71             return false; 72         } 73  74         //获取所有文件文件名 75         public List<string> GetFileNames() 76         { 77             string path = Server.MapPath("File"); 78             DirectoryInfo dir = new DirectoryInfo(path); 79             FileInfo[] files = dir.GetFiles(); 80             List<string> list = new List<string>(); 81             foreach (FileInfo item in files) 82             { 83                 list.Add(item.Name); 84             } 85             return list; 86         } 87  88         //绑定dropdownList 89         private void BindDropDownList() 90         { 91             DropDownList1.DataSource = GetFileNames(); 92             DropDownList1.DataBind(); 93             DropDownList1.Items.Insert(0, "请选择文件"); 94         } 95  96         //下载指定文件 97         protected void Button2_Click(object sender, EventArgs e) 98         { 99             if(DropDownList1.SelectedIndex!=0)100             {101                 string fileName = DropDownList1.SelectedItem.ToString();//客户端保存的文件名102                 string filePath = Server.MapPath("File/") + fileName;//路径103                 DownLoadFile(fileName, filePath);104             }105             else106             {107                 Page.ClientScript.RegisterClientScriptBlock(Page.ClientScript.GetType(), "myscripts", "<script>alert(\"请选择下载文件!\");</script>");108             }109         }110 111 112         /// <summary>113         /// 文件下载114         /// </summary>115         /// <param name="fileName">文件名称</param>116         /// <param name="filePath">文件绝对路径</param>117         public void DownLoadFile(string fileName, string filePath)118         {119 120             ////WriteFile分块下载121             string browserType = Request.Browser.Browser.ToString();//获取浏览器类型122 123             string fileNewName = "";124             if (browserType != "Firefox")//火狐浏览器不需要进行编码，文件名称就能显示125             {126                 fileNewName = HttpUtility.UrlEncode(fileName); //如果不是火狐浏览器，加上HttpUtility.UrlEncode()方法，防止文件下载时，文件名乱码127             }128             else129             {130                 fileNewName = fileName;131             }132 133             System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath);134 135             if (fileInfo.Exists == true)136             {137                 const long ChunkSize = 102400;//100K 每次读取文件，只读取100K，这样可以缓解服务器的压力138                 byte[] buffer = new byte[ChunkSize];139 140                 Response.Clear();141                 System.IO.FileStream iStream = System.IO.File.OpenRead(filePath);142                 long dataLengthToRead = iStream.Length;//获取下载的文件总大小143                 Response.ContentType = "application/octet-stream";144                 Response.AddHeader("Content-Disposition", "attachment; filename=" + fileName);145 146                 while (dataLengthToRead > 0 && Response.IsClientConnected)147                 {148                     int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小149                     Response.OutputStream.Write(buffer, 0, lengthRead);150                     Response.Flush();151                     dataLengthToRead = dataLengthToRead - lengthRead;152                 }153                 Response.Close();154                 155             }156         }157   158 159     }160 }