標籤：generic 問題 檔案的 datetime sub 微軟 text http date
檔案上傳：
所用控制項：FileUpload
使用時的思路：
1、判斷使用者是否選中了檔案
FileUpload.FileName擷取選中的檔案名稱，判斷長度，如果長度大於零就代表已經選擇了檔案
JS端：通過ID擷取控制項，然後控制項的value擷取選中的檔案名稱
2、將檔案儲存到伺服器上
FileUpload.SaveAs("絕對路徑");
3、獲得絕對路徑
先編寫相對路徑：比如"UpLoads/abc.txt"
再把路徑映射成絕對路徑：Server.MapPath("UpLoads/abc.txt");
4、保留原檔案的類型和檔案名稱
相對路徑改為"UpLoads/" + FileUpload1.FileName;
5、防止檔案重名覆蓋的問題
"UpLoads/" + Request.Cookies["user"].Value + DateTime.Now.ToString("yyyyMMddhhmmssms") + FileUpload1.FileName;
也就是在檔案名稱前面拼接上登陸的使用者名稱以及操作的時間，精確到毫秒
6、限制使用者可選的檔案類型
給控制項添加屬性accept=".jpg,.png,.jpeg,.txt"
但在開啟的對話方塊中，仍然可以選擇全部檔案，只能通過JS端來限制：
document.getElementById("Button1").onclick = function () { var fileName = document.getElementById("FileUpload1").value; var name = fileName.substr(fileName.length - 4, 4); var name1 = fileName.substr(fileName.length - 5, 5); if (name != ".jpg" && name != ".png" && name != ".txt" && name1 != ".jpeg") { alert("請選擇正確的檔案！"); return false; } };
圖片加浮水印:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="shuiyin.aspx.cs" Inherits="shuiyin" %><!DOCTYPE html><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title></title></head><body> <form id="form1" runat="server"> <div> <asp:FileUpload ID="FileUpload1" runat="server" /><asp:Button ID="Button1" runat="server" Text="Button" /> <asp:Image ID="Image1" runat="server" /> </div> </form></body></html>
using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;//一定要加上這個引用!using System.Drawing;public partial class shuiyin : System.Web.UI.Page{ protected void Page_Load(object sender, EventArgs e) { Button1.Click += Button1_Click; } void Button1_Click(object sender, EventArgs e) { //獲得要上傳的圖片 System.Drawing.Image img = System.Drawing.Image.FromStream(FileUpload1.FileContent); //加上浮水印 //把獲得圖片變成一個GDI畫圖圖面,開始繪製 Graphics g = Graphics.FromImage(img); //分別對應(浮水印內容,浮水印字型,浮水印顏色,浮水印位置) g.DrawString("哈哈哈", new Font("微軟雅黑", 20), new SolidBrush(Color.Red), new PointF(0, 0)); //儲存圖片 //img指檔案夾名稱,後面給要加浮水印的檔案重新命名 string ul = "img/" + DateTime.Now.ToString("yyyyMMddHHmmssms") + FileUpload1.FileName; //儲存並產生絕對路徑 img.Save(Server.MapPath(ul)); //把效果展示出來看一下 Image1.ImageUrl = ul; }}
檔案上傳,圖片加浮水印
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