一、图片加水印
前台代码：
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default1.aspx.cs" Inherits="Default1" %>
<!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="上传" /><br />
<asp:Image ID="Image1" runat="server" />
</div>
</form>
</body>
</html>
后台代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;
public partial class Default1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Button1.Click += Button1_Click;
}
void Button1_Click(object sender, EventArgs e)
{
//1、先把图片获取出来
//咱们要画画的画布
System.Drawing.Image img = System.Drawing.Image.FromStream(FileUpload1.FileContent);
//2、往上面画上水印
Graphics g = Graphics.FromImage(img);//这个是绘制方法，等号右边是往那张图片上绘制
string s = "http://www.itnba.com"; //绘制的字符串
Font f = new Font("微软雅黑",18);//绘制使用的字体
SolidBrush b = new SolidBrush(Color.Red);//绘制使用的刷子，设置颜色
g.DrawString(s, f, b, 0, 0); //绘制完毕
//3、保存到服务器指定路径，并且在Image控件中显示
string path = Server.MapPath("Uploads/" + FileUpload1.FileName);
img.Save(path);//将绘制完的图片保存，注意：千万不要把选择的图片保存
Image1.ImageUrl = "Uploads/" + FileUpload1.FileName;
}
}
二、图片验证码
1、首先引用命名空间：system.Drawing;
2、将aspx页面当做图片路径，在load事件中进行绘制并保存在内存流中
前台代码：
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default2.aspx.cs" Inherits="Default2" %>
<!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>
请输入验证码：<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox><asp:Image ID="Image1" runat="server" ImageUrl="~/YZM.aspx" /><br />
<asp:Button ID="Button1" runat="server" Text="验证" /><asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
</div>
</form>
</body>
</html>
<script type="text/javascript">
var aaa = 0;
document.getElementById(‘Image1‘).onclick = function () {
this.setAttribute("src", "yzm.aspx?id="+aaa);
aaa++;
};
</script>
后台代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class Default2 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Button1.Click += Button1_Click;
}
void Button1_Click(object sender, EventArgs e)
{
if (TextBox1.Text == Session["YZM"].ToString())
{
Label1.Text = "正确！";
}
else
{
Label1.Text = "错误！";
}
}
}
生成图片验证码的后台代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;
public partial class YZM : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//1、准备画布
Bitmap img = new Bitmap(60, 30);
//2、往画布上绘制验证码
string all = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
string aaa = "";
Random r = new Random();
for (int i = 0; i < 4; i++)
{
aaa += all.Substring(r.Next(all.Length), 1);
}
Session["YZM"] = aaa;
Graphics g = Graphics.FromImage(img);
Font f = new Font("微软雅黑",16);
SolidBrush b = new SolidBrush(Color.Green);
g.DrawString(aaa, f, b, 0, 0);
img.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Png);
}
}
时间： 2024-12-06 00:05:14