C#byte数组与Image的相互转换实例代码
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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