程式師世界 >> 編程語言 >> .NET網頁編程 >> .NET實例教程 >> 使用FileUpload控件上傳圖片並自動生成縮略圖、自動生成帶文字和圖片的水印圖

使用FileUpload控件上傳圖片並自動生成縮略圖、自動生成帶文字和圖片的水印圖

編輯：.NET實例教程

本文借助vs2005中自帶的FileUpload控件實現圖片文件的上傳並生成縮略圖。
    實現過程：選擇圖片上傳成功後，取得已經存在服務器的文件生成縮略圖，並且判斷是否是圖片類型的文件，這個的判斷可以在程序中修改，本程序只是判斷了“image/bmp”、“image/gif”、“image/pjpeg”三種類型。
    代碼如下：
    upfile.ASPx文件
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="upfile.ASPx.cs" Inherits="upfile_upfile" %>

<!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>無標題頁</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <ASP:FileUpload ID="FileUpload1" runat="server" />
        <ASP:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="上傳" /><br />
        <asp:Label ID="Label1" runat="server"></ASP:Label></div>
    </form>
</body>
</Html>
    upfile.ASPx.cs文件
using System;
using System.Data;
using System.Configuration;
using System.Collections;
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.IO;

public partial class upfile_upfile : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{ }

    protected void Button1_Click(object sender, EventArgs e)
    {
        if (FileUpload1.HasFile)
        {
            string fileContentType = FileUpload1.PostedFile.ContentType;
            if (fileContentType == "image/bmp" || fileContentType == "image/gif" || fileContentType == "image/pjpeg")
            {
                string name = FileUpload1.PostedFile.FileName;                  // 客戶端文件路徑

                FileInfo file = new FileInfo(name);
                string fileName = file.Name;                                    // 文件名稱
                string fileName_s = "s_" + file.Name;                           // 縮略圖文件名稱
                string fileName_sy = "sy_" + file.Name;                         // 水印圖文件名稱（文字）
                string fileName_syp = "syp_" + file.Name;                       // 水印圖文件名稱（圖片）
                string webFilePath = Server.MapPath("file/" + fileName);        // 服務器端文件路徑
                string webFilePath_s = Server.MapPath("file/" + fileName_s);　　// 服務器端縮略圖路徑
                string webFilePath_sy = Server.MapPath("file/" + fileName_sy);　// 服務器端帶水印圖路徑(文字)
                string webFilePath_syp = Server.MapPath("file/" + fileName_syp);　// 服務器端帶水印圖路徑(圖片)
                string webFilePath_sypf = Server.MapPath("file/shuiyin.jpg");　// 服務器端水印圖路徑(圖片)

                if (!File.Exists(webFilePath))
                {
                    try
                    {
                        FileUpload1.SaveAs(webFilePath);                                // 使用 SaveAs 方法保存文件
                        AddShuiYinWord(webFilePath, webFilePath_sy);

;     AddShuiYinPic(webFilePath, webFilePath_syp, webFilePath_sypf);
                        MakeThumbnail(webFilePath, webFilePath_s, 130, 130, "Cut");     // 生成縮略圖方法
                        Label1.Text = "提示：文件“" + fileName + "”成功上傳，並生成“" + fileName_s + "”縮略圖，文件類型為：" + FileUpload1.PostedFile.ContentType + "，文件大小為：" + FileUpload1.PostedFile.ContentLength + "B";
                    }
                    catch (Exception ex)
                    {
                        Label1.Text = "提示：文件上傳失敗，失敗原因：" + ex.Message;
                    }
                }
                else
                {
                    Label1.Text = "提示：文件已經存在，請重命名後上傳";
                }
            }
            else
            {
                Label1.Text = "提示：文件類型不符";
            }
        }
    }
    /**//// <summary>
    /// 生成縮略圖
    /// </summary>
    /// <param name="originalImagePath">源圖路徑（物理路徑）</param>
    /// <param name="thumbnailPath">縮略圖路徑（物理路徑）</param>
    /// <param name="width">縮略圖寬度</param>
    /// <param name="height">縮略圖高度</param>
    /// <param name="mode">生成縮略圖的方式</param>
    public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
    {
        System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);

int towidth = width;
int toheight = height;

        int x = 0;
        int y = 0;
        int ow = originalImage.Width;
        int oh = originalImage.Height;

        switch (mode)
        {
            case "HW"://指定高寬縮放（可能變形）
                break;
            case "W"://指定寬，高按比例
                toheight = originalImage.Height * width / originalImage.Width;
                break;
            case "H"://指定高，寬按比例
                towidth = originalImage.Width * height / originalImage.Height;
                break;
            case "Cut"://指定高寬裁減（不變形）
                if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                {
                    oh = originalImage.Height;
                    ow = originalImage.Height * towidth / toheight;
                    y = 0;
                    x = (originalImage.Width - ow) / 2;
                }
                else
                {
                    ow = originalImage.Width;
                    oh = originalImage.Width * height / towidth;
                    x = 0;
                    y = (originalImage.Height - oh) / 2;
                }
                break;
            default:
                break;
        }

//新建一個bmp圖片
System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);

//新建一個畫板
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);

//設置高質量插值法
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

//設置高質量,低速度呈現平滑程度
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

//清空畫布並以透明背景色填充
g.Clear(System.Drawing.Color.Transparent);

        //在指定位置並且按指定大小繪制原圖片的指定部分
        g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight),
            new System.Drawing.Rectangle(x, y, ow, oh),
            System.Drawing.GraphicsUnit.Pixel);

        try
        {
            //以jpg格式保存縮略圖
            bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
        }
        catch (System.Exception e)
        {
         throw e;
        }
        finally
        {
            originalImage.Dispose();
            bitmap.Dispose();
            g.Dispose();
        }
    }

    /**//// <summary>
    /// 在圖片上增加文字水印
    /// </summary>
    /// <param name="Path">原服務器圖片路徑</param>
    /// <param name="Path_sy">生成的帶文字水印的圖片路徑</param>
    protected void AddShuiYinWord(string Path, string Path_sy)
    {
        string addText = "測試水印";
        System.Drawing.Image image = System.Drawing.Image.FromFile(Path);
        System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);
        g.DrawImage(image, 0, 0, image.Width, image.Height);
        System.Drawing.Font f = new System.Drawing.Font("Verdana", 16);
        System.Drawing.Brush b = new System.Drawing.SolidBrush(System.Drawing.Color.Blue);

g.DrawString(addText, f, b, 15, 15);
g.Dispose();

        image.Save(Path_sy);
        image.Dispose();
    }

    /**//// <summary>
    /// 在圖片上生成圖片水印
    /// </summary>
    /// <param name="Path">原服務器圖片路徑</param>
    /// <param name="Path_syp">生成的帶圖片水印的圖片路徑</param>
    /// <param name="Path_sypf">水印圖片路徑</param>
    protected void AddShuiYinPic(string Path, string Path_syp, string Path_sypf)
    {
        System.Drawing.Image image = System.Drawing.Image.FromFile(Path);
        System.Drawing.Image copyImage = System.Drawing.Image.FromFile(Path_sypf);
        System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);
        g.DrawImage(copyImage, new System.Drawing.Rectangle(image.Width - copyImage.Width, image.Height - copyImage.Height, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width,copyImage.Height, System.Drawing.GraphicsUnit.Pixel);
        g.Dispose();

        image.Save(Path_syp);
        image.Dispose();
    }
}