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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