winform程序上传图片并生成一个固定大小的图片的代码

Question

winform程序上传图片并为该图生成一个固定尺寸图片的代码

Answer 1

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Collections;
using System.Drawing.Imaging;
using System.Drawing;namespace File
{
    public class CreateSmallImage
    {
        static Hashtable htmimes = new Hashtable();
        internal readonly string AllowExt = ".jpe|.jpeg|.jpg|.png|.tif|.tiff|.bmp|.gif";
        public CreateSmallImage()
        {
            #region   
            htmimes[".jpe"]= "image/jpeg";
            htmimes[".jpeg"] = "image/jpeg";
            htmimes[".jpg"] = "image/jpeg";
            htmimes[".png"] = "image/png";
            htmimes[".tif"] = "image/tiff";
            htmimes[".tiff"] = "image/tiff";
            htmimes[".bmp"] = "image/bmp";
            htmimes[".gif"] = "image/gif";
            #endregion 
        }        #region   Helper
        ///   <summary> 
        ///   获取图像编码解码器的所有相关信息 
        ///   </summary> 
        ///   <param   name= "mimeType "> 包含编码解码器的多用途网际邮件扩充协议   (MIME)   类型的字符串 </param> 
        ///   <returns> 返回图像编码解码器的所有相关信息 </returns> 
        static   ImageCodecInfo   GetCodecInfo(string   mimeType) 
        { 
          ImageCodecInfo[]   CodecInfo   =   ImageCodecInfo.GetImageEncoders(); 
          foreach(ImageCodecInfo   ici   in   CodecInfo) 
          { 
            if(ici.MimeType   ==   mimeType)return   ici; 
          } 
          return   null; 
        }         ///   <summary> 
        ///   检测扩展名的有效性 
        ///   </summary> 
        ///   <param   name= "sExt "> 文件名扩展名 </param> 
        ///   <returns> 如果扩展名有效,返回true,否则返回false. </returns> 
        bool   CheckValidExt(string   sExt) 
        {       
          bool   flag=false; 
          string[]   aExt   =   AllowExt.Split('|'); 
          foreach(string   filetype   in   aExt) 
          { 
            if(filetype.ToLower()==sExt) 
            { 
              flag   =   true; 
              break; 
            } 
          }       
          return   flag; 
        }         ///   <summary> 
        ///   保存图片 
        ///   </summary> 
        ///   <param   name= "image "> Image   对象 </param> 
        ///   <param   name= "savePath "> 保存路径 </param> 
        ///   <param   name= "ici "> 指定格式的编解码参数 </param> 
        void   SaveImage(System.Drawing.Image   image,string   savePath,ImageCodecInfo   ici) 
        { 
          //设置   原图片   对象的   EncoderParameters   对象 
          EncoderParameters   parameters   =   new   EncoderParameters(1); 
          parameters.Param[0]   =   new   EncoderParameter(Encoder.Quality,   ((long)   90)); 
          image.Save(savePath,   ici,   parameters); 
          parameters.Dispose(); 
        } 
        #endregion             #region   Methods            ///   <summary> 
            ///   生成缩略图 
            ///   </summary> 
            ///   <param   name= "sourceImagePath "> 原图片路径(相对路径) </param> 
            ///   <param   name= "thumbnailImagePath "> 生成的缩略图路径,如果为空则保存为原图片路径(相对路径) </param> 
            ///   <param   name= "thumbnailImageWidth "> 缩略图的宽度（高度与按源图片比例自动生成） </param> 
         public void ToThumbnailImages(string sourceImagePath, string thumbnailImagePath) 
        { 
          string   SourceImagePath   =   sourceImagePath; 
          string   ThumbnailImagePath   =   thumbnailImagePath; 
          string   sExt   =   SourceImagePath.Substring(SourceImagePath.LastIndexOf(".")).ToLower(); 
          if(SourceImagePath.ToString()==System.String.Empty)   throw   new   NullReferenceException( "SourceImagePath   is   null! "); 
          if(!CheckValidExt(sExt)) 
          { 
                throw   new   ArgumentException( "原图片文件格式不正确,支持的格式有[   "+   AllowExt   + "   ] ", "SourceImagePath "); 
          } 
          //从   原图片   创建   Image   对象 
          System.Drawing.Image   image   =   System.Drawing.Image.FromFile(HttpContext.Current.Server.MapPath(SourceImagePath));
          double num; 
          int width = image.Width;
          int height = image.Height; 
          //计算图片的比例           if (width>120||height>120)
          {
              //ThumbnailImageWidth = width / 3;
              //num = height / 3;
              if (width > height)
              {
                  num = 120 / width;
                  width = 120;
                  height =(int)(height * num);
              }
              else
              {
                  num = 120 /(double)height;
                  height = 120;
                  width = (int)(width * num);
              }          }
          //用指定的大小和格式初始化   Bitmap   类的新实例 
          Bitmap bitmap = new Bitmap(width,height, PixelFormat.Format32bppArgb); 
          //从指定的   Image   对象创建新   Graphics   对象 
          Graphics   graphics   =   Graphics.FromImage(bitmap); 
          //清除整个绘图面并以透明背景色填充 
          graphics.Clear(Color.Transparent); 
          //在指定位置并且按指定大小绘制   原图片   对象 
          graphics.DrawImage(image, new Rectangle(0, 0,width,height)); 
          image.Dispose();         
          try 
          {       
            //将此   原图片   以指定格式并用指定的编解码参数保存到指定文件   
            string   savepath   =   (ThumbnailImagePath==null?SourceImagePath:ThumbnailImagePath);     
            SaveImage(bitmap,HttpContext.Current.Server.MapPath(savepath),GetCodecInfo((string)htmimes[sExt])); 
          } 
          catch(System.Exception   e) 
          { 
            throw   e; 
          } 
          finally 
          { 
            bitmap.Dispose();             
            graphics.Dispose(); 
          } 
        }
        #endregion 
    }
}这是asp.net你改改。winform应该也可以用