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  • 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(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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  • 原文地址:https://www.cnblogs.com/wzwyc/p/6292204.html
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