文件上傳限制大小 dotnet/C#

private void Button1_Click(object sender, System.EventArgs e)

              {

                     if (File1.PostedFile != null)

                     {

                            //上傳文件的文件名（含完整路徑）

                            string fileName = File1.PostedFile.FileName ;

                            //上傳文件的大小（byte）

                            int fileLength = File1.PostedFile.ContentLength ; km

                            string sMsg = null;

                            //判斷文件大小是否超過200K

                            if (fileLength > (200*1024))

                            {

                                   sMsg = fileName + "文件超過200K字節！";

                            }

                            else

                            {

                                   //取文件名

                                   fileName = fileName.Substring (fileName.LastIndexOf (@"\"));

                                   //使用SaveAs方法，將文件保存在項目路徑\upload目錄下

                                   File1.PostedFile.SaveAs (HttpRuntime.AppDomainAppPath  + @"upload\" + fileName);

                                   sMsg = "成功上傳文件：" + fileName + "文件大小：" + fileLength + "字節" + "文件類型：" + File1.PostedFile.ContentType  ;

                            }

                            //使用JavaScript顯示操作結果信息

                            Response.Write ("<script language='JavaScript'>window.alert('" + sMsg + "');</script>");

                     }

              }