asp.net图片上传及生成缩略图

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.IO;
using System.Text;
using System.Drawing;
/// <summary>
/// 图片上传类
/// </summary>
public class uploadImg
{
public uploadImg() { }
/*调用:
只要先实例化类之后，设置想要的属性。
UpLoadIMG（this.fileupload1）
输入文件上传控件的ID作为参数就可以了。
*/
private static string _MSG;
private string OFullName;// 保存时的完整路径.原图
private string TFullName;// 保存时的完整路径.缩略图
private static string _OFileName;// 保存时的图片名称.原图
private string TFileName;// 保存时的图片名称.缩略图
//private string _tfullname = "0";
//private string _ofilename = "0";
//private string _tfilename = "0";
private string _tprefix = "small_";
private int _limitwidth = 3072;
private int _limitheight = 2304;
private int _twidth = 100;
private int _theight = 100;
private int _size = 3000000;
private bool _israte;
private bool _iscreate;
private string _path = "upload";
/// <summary>
/// 信息
/// </summary>
public static string MSG
{
get { return _MSG; }
set { _MSG = value; }
}
/// <summary>
/// 缩略图前缀
/// </summary>
public string TPrefix
{
get { return _tprefix; }
set { _tprefix = value; }
}
/// <summary>
/// 原图最大宽度
/// </summary>
public int LimitWidth
{
get { return _limitwidth; }
set { _limitwidth = value; }
}
/// <summary>
/// 原图最大高度
/// </summary>
public int LimitHeight
{
get { return _limitheight; }
set { _limitheight = value; }
}
/// <summary>
/// 缩略图最大宽度
/// </summary>
public int TWidth
{
get { return _twidth; }
set { _twidth = value; }
}
/// <summary>
/// 缩略图最大高度
/// </summary>
public int THeight
{
get { return _theight; }
set { _theight = value; }
}
/// <summary>
/// 文件大小
/// </summary>
public int Size
{
get { return _size; }
set { _size = value; }
}
/// <summary>
/// 是否成比例
/// </summary>
public bool IsRate
{
get { return _israte; }
set { _israte = value; }
}
/// <summary>
/// 是否生成缩略图
/// </summary>
public bool IsCreate
{
get { return _iscreate; }
set { _iscreate = value; }
}
/// <summary>
/// 存放图片的文件夹名称
/// </summary>
public string Path
{
get { return _path; }
set { _path = value; }
}
/// <summary>
/// 原图名称
/// </summary>
public static string OFileName
{
get { return _OFileName; }
set { _OFileName = value; }
}
/// <summary>
/// 图片上传(默认:"等比压缩,限定上传尺寸2048*1536,缩略图尺寸100*100,限定上传大小1MB,存放在根目录upload中")
/// </summary>
/// <param name="UploadFile">文件上传控件</param>
/// <returns>返回是否成功保存图片</returns>
public bool UpLoadIMG(FileUpload UploadFile)
{
if (UploadFile.HasFile)//检查是否已经选择文件
{
string filename = UploadFile.FileName.ToLower();
int i = filename.LastIndexOf(".");
filename = filename.Substring(i, filename.Length - i);
if (!(filename == ".jpg" || filename == ".jpeg" || filename == ".gif" || filename == ".png" || filename == ".bmp"))
{
MSG = "文件格式不正确，只能为jpeg,jpg,gif,png或bmp !";
return false;
}//检查上传文件的格式是否有效
if (UploadFile.PostedFile.ContentLength == 0 || UploadFile.PostedFile.ContentLength >= Size)
{
MSG =string.Format("图片的大小应小于 {0} M!",Math.Round(_size/1024.0/1024.0,2));
return false;
}//检查图片文件的大小
//生成原图
Stream oStream = UploadFile.PostedFile.InputStream;
System.Drawing.Image oImage = System.Drawing.Image.FromStream(oStream);
int owidth = oImage.Width; //原图宽度
int oheight = oImage.Height; //原图高度
if (owidth > LimitWidth || oheight > LimitHeight)
{
MSG =string.Format("图片尺寸应小于{0}*{1}",_limitwidth,this._limitheight);
return false;
}//检查是否超出规定尺寸
if (IsRate)
{
//按比例计算出缩略图的宽度和高度
if (owidth >= oheight)
{
THeight = (int)Math.Floor(Convert.ToDouble(oheight) * (Convert.ToDouble(TWidth) / Convert.ToDouble(owidth)));//等比设定高度
}
else
{
TWidth = (int)Math.Floor(Convert.ToDouble(owidth) * (Convert.ToDouble(THeight) / Convert.ToDouble(oheight)));//等比设定宽度
}
}
//生成缩略原图
Bitmap tImage = new Bitmap(TWidth, THeight);
Graphics g = Graphics.FromImage(tImage);
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic; //设置高质量插值法
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//设置高质量,低速度呈现平滑程度
g.Clear(Color.Transparent); //清空画布并以透明背景色填充
g.DrawImage(oImage, new Rectangle(0, 0, TWidth, THeight), new Rectangle(0, 0, owidth, oheight), GraphicsUnit.Pixel);
Random orandom = new Random();
string oStringRandom = orandom.Next(999999999).ToString();//生成9位随机数字
//格式化日期作为文件名
string oStringTime = string.Format("{0:yyyyMMddHHmmss}", DateTime.Now);
OFileName =oStringTime + oStringRandom + filename;
TFileName = TPrefix + oStringTime + oStringRandom + filename;
string SavePath = HttpContext.Current.Server.MapPath("~") + "\\" + Path + "\\";
if (!Directory.Exists(SavePath))
{
Directory.CreateDirectory(SavePath);//在根目录下建立文件夹
}
OFullName = SavePath + OFileName;
TFullName = SavePath + TFileName;
//开始保存图片至服务器
try
{
switch (filename)
{
case ".jpeg":
case ".jpg":
{
oImage.Save(OFullName, System.Drawing.Imaging.ImageFormat.Jpeg);
if(IsCreate)tImage.Save(TFullName, System.Drawing.Imaging.ImageFormat.Jpeg);
break;
}
case ".gif":
{
oImage.Save(OFullName, System.Drawing.Imaging.ImageFormat.Gif);
if (IsCreate) tImage.Save(TFullName, System.Drawing.Imaging.ImageFormat.Gif);
break;
}
case ".png":
{
oImage.Save(OFullName, System.Drawing.Imaging.ImageFormat.Png);
if (IsCreate) tImage.Save(TFullName, System.Drawing.Imaging.ImageFormat.Png);
break;
}
case ".bmp":
{
oImage.Save(OFullName, System.Drawing.Imaging.ImageFormat.Bmp);
if (IsCreate)tImage.Save(TFullName, System.Drawing.Imaging.ImageFormat.Bmp);
break;
}
}
MSG = "图片上传成功!";
//保存路径+完整文件名
string _SavePath = "/" + Path + "/";
OFullName = _SavePath + OFileName;
TFullName = _SavePath + TFileName;
return true;
}
catch (Exception ex)
{
MSG = ex.Message;
return false;
}
finally
{
//释放资源
oImage.Dispose();
g.Dispose();
tImage.Dispose();
}
}
else
{
MSG = "请先选择需要上传的图片!";
return false;
}
}
}