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原文地址:http://www.cnblogs.com/luxiaoxun/p/3378416.html
功能需求:
1、把一张图片(png bmp jpeg bmp gif)转换为byte数组存放到数据库。
2、把从数据库读取的byte数组转换为Image对象,赋值给相应的控件显示。
3、从图片byte数组得到对应图片的格式,生成一张图片保存到磁盘上。
这里的Image是System.Drawing.Image。
//Get an image from file
Image image = Image.FromFile("D:\\test.jpg");
Bitmap bitmap = new Bitmap("D:\\test.jpg");
以下三个函数分别实现了上述三个需求:
- using System;
- using System.Collections.Generic;
- using System.Drawing;
- using System.Drawing.Imaging;
- using System.IO;
- using System.Linq;
- using System.Text;
- namespace NetUtilityLib
- {
- public static class ImageHelper
- {
- /// <summary>
- /// Convert Image to Byte[]
- /// </summary>
- /// <param name="image"></param>
- /// <returns></returns>
- public static byte[] ImageToBytes(Image image)
- {
- ImageFormat format = image.RawFormat;
- using (MemoryStream ms = new MemoryStream())
- {
- if (format.Equals(ImageFormat.Jpeg))
- {
- image.Save(ms, ImageFormat.Jpeg);
- }
- else if (format.Equals(ImageFormat.Png))
- {
- image.Save(ms, ImageFormat.Png);
- }
- else if (format.Equals(ImageFormat.Bmp))
- {
- image.Save(ms, ImageFormat.Bmp);
- }
- else if (format.Equals(ImageFormat.Gif))
- {
- image.Save(ms, ImageFormat.Gif);
- }
- else if (format.Equals(ImageFormat.Icon))
- {
- image.Save(ms, ImageFormat.Icon);
- }
- byte[] buffer = new byte[ms.Length];
- //Image.Save()会改变MemoryStream的Position,需要重新Seek到Begin
- ms.Seek(0, SeekOrigin.Begin);
- ms.Read(buffer, 0, buffer.Length);
- return buffer;
- }
- }
- /// <summary>
- /// Convert Byte[] to Image
- /// </summary>
- /// <param name="buffer"></param>
- /// <returns></returns>
- public static Image BytesToImage(byte[] buffer)
- {
- MemoryStream ms = new MemoryStream(buffer);
- Image image = System.Drawing.Image.FromStream(ms);
- return image;
- }
- /// <summary>
- /// Convert Byte[] to a picture and Store it in file
- /// </summary>
- /// <param name="fileName"></param>
- /// <param name="buffer"></param>
- /// <returns></returns>
- public static string CreateImageFromBytes(string fileName, byte[] buffer)
- {
- string file = fileName;
- Image image = BytesToImage(buffer);
- ImageFormat format = image.RawFormat;
- if (format.Equals(ImageFormat.Jpeg))
- {
- file += ".jpeg";
- }
- else if (format.Equals(ImageFormat.Png))
- {
- file += ".png";
- }
- else if (format.Equals(ImageFormat.Bmp))
- {
- file += ".bmp";
- }
- else if (format.Equals(ImageFormat.Gif))
- {
- file += ".gif";
- }
- else if (format.Equals(ImageFormat.Icon))
- {
- file += ".icon";
- }
- System.IO.FileInfo info = new System.IO.FileInfo(file);
- System.IO.Directory.CreateDirectory(info.Directory.FullName);
- File.WriteAllBytes(file, buffer);
- return file;
- }
- }
- }
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