C# byte数组与Image的相互转换
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(, SeekOrigin.Begin);
ms.Read(buffer, , 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;
}
}
}