Asp.net上传图片并添加水印

最新推荐文章于 2024-10-13 20:54:37 发布

susieweijs

最新推荐文章于 2024-10-13 20:54:37 发布

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CC 4.0 BY-SA版权

文章标签： session string server stylesheet asp

本文链接：https://blog.youkuaiyun.com/susieweijs/article/details/5660568

本文介绍了一个使用ASP.NET实现的图片上传功能，并详细展示了如何在上传后的图片上添加文字水印。代码中包含了前端界面的设计及后端处理逻辑，如文件格式验证、图片保存及水印绘制等关键步骤。

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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