C#生成缩略图源码

先看调用的方法：

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;public partial class test_Default : System.Web.UI.Page{    protected void Page_Load(object sender, EventArgs e)    {        generalImage();    }    private void generalImage()    {        string savePath = @"images/123.jpg";//原图路径        string smallPath = @"images/small/123.jpg";//要生成的小图        savePath = Server.MapPath(savePath);//这一步别忘了。        smallPath = Server.MapPath(smallPath);//同样这里也不要忘了。        YD.Common.ImageClass imageClass = new YD.Common.ImageClass();        imageClass.ShowThumbnail(savePath, smallPath, 200, 153);//这样调用    }}

生成小图的类：

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;/// <summary>/// ImageClass 的摘要说明/// </summary>namespace YD.Common{    public class ImageClass    {        public bool ThumbnailCallback()        {            return false;        }        public void ShowThumbnail(string oldfile, string newfile, int white, int height)        {            System.Drawing.Image image = System.Drawing.Image.FromFile(oldfile);            //获取原图高度和宽度            int oldh = image.Height;            int oldw = image.Width;            int neww, newh;            neww = white; newh = height;   //直接设定新图的高宽,,            try            {                System.Drawing.Image.GetThumbnailImageAbort callb = new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);                System.Drawing.Image bt = new System.Drawing.Bitmap(neww, newh);                System.Drawing.Graphics gr = System.Drawing.Graphics.FromImage(bt);                gr.Clear(Color.White);                gr.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;                gr.DrawImage(image, new Rectangle(0, 0, neww, newh), 0, 0, oldw, oldh, GraphicsUnit.Pixel);                switch (oldfile.Substring(oldfile.Length - 3).ToUpper())                {                    case "JPG":                        bt.Save(newfile, ImageFormat.Jpeg);                        break;                    case "GIF":                        bt.Save(newfile, ImageFormat.Gif);                        break;                    case "PNG":                        bt.Save(newfile, ImageFormat.Png);                        break;                    default:                        bt.Save(newfile, ImageFormat.Jpeg);                        break;                }                gr.Dispose();                bt.Dispose();                image.Dispose();            }            catch { }        }    }}