前台界面：
<%@ Page Language="C#" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Asp.net上传图片并添加水印</title>
<link href="css/yx.css" rel="stylesheet" type="text/css" />
</head>
<body>
<form id="form1" runat="server">
<div id="top">
Asp.Net上传并添加水印
</div>
<div id="content">
选择上传图片：<asp:FileUpload ID="upFileTest" runat="server" /><br />
<br />
<br />
<asp:RequiredFieldValidator ID="vUpFile" runat="server" ControlToValidate="upFileTest"
ErrorMessage="请选择要上传的文件！"></asp:RequiredFieldValidator><br />
<br />
<br />
<br />
<asp:Button ID="btnText" runat="server" OnClick="btnText_Click" Text="上传并添加文字水印" />
<br />
<br />
<br />
<br />
<asp:Label ID="lblStatus" runat="server"></asp:Label></div>
</form>
</body>
</html>
后台代码：
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
public partial class _Default : System.Web.UI.Page
{
/// <summary>
///
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
lblStatus.Visible = false;
}
}
private void Show(string str)
{
Response.Write("<script language='javascript'>alert('" + str + "')</script>");
}
private void upLoad()
{
string fullName = upFileTest.PostedFile.FileName;
string fileName = fullName.Substring(fullName.LastIndexOf("\\") + 1);
string marks = fullName.Substring(fullName.LastIndexOf(".") + 1);
if (marks != "jpg" && marks != "gif" && marks != "JPG" && marks != "GIF")
{
Show("上传的文件格式不正确，请重新选择！");
}
else
{
string upFileName = Server.MapPath("upLoadFiles") + "\\" + System.DateTime.Now.ToString("yyyyMMddhhmmss") + "." + marks;
Session["filePath"] = upFileName;
Session["marks"] = marks;
upFileTest.PostedFile.SaveAs(upFileName);
}
}
protected void btnText_Click(object sender, EventArgs e)
{
upLoad();
//开始加文字水印
System.Drawing.Image img = System.Drawing.Image.FromFile(Session["filePath"].ToString());
Graphics g = Graphics.FromImage(img);
g.DrawImage(img, 0, 0, img.Width, img.Height);
Font f = new Font("Verdana", 16);
Brush b = new SolidBrush(Color.Red);
string str = "Test";
g.DrawString(str, f,b, 10, 10);
g.Dispose();
string newFilePath = Server.MapPath("upLoadFiles") + "\\" + System.DateTime.Now.ToString("yyyyMMddhhmmss") + "." + Session["marks"].ToString();
img.Save(newFilePath);
img.Dispose();
if(File.Exists(Session["filePath"].ToString()))
{
File.Delete(Session["filePath"].ToString());
}
lblStatus.Visible = true;
lblStatus.Text = "水印绘制成功!";
}
}
Ps，调用system.drawing.image.save方法，可能因为没有读写权限而报错，添加iis访问权限即可
