c#文件保存

 1 //HttpPost
 2 HttpRequest request = HttpContext.Current.Request;
 3 HttpFileCollection filelist = request.Files;
 4 HttpPostedFile file = filelist[0];
 5 file.SaveAs(filename);
 6 
 7 //转Bitmap
 8 //1、byte[]
 9 MemoryStream ms = new MemoryStream(bytes);
10 Bitmap bmp = new Bitmap(ms);
11 //2、filename
12 Bitmap bmp= new Bitmap(filename);
13 //3、url（使用Flurl)
14 Stream stream = await url.GetStreamAsync();
15 Bitmap bmp = new Bitmap(stream);
16 
17 //输出
18 //1、文件
19 bmp.Save(filename, System.Drawing.Imaging.ImageFormat.Jpeg);
20 //2、byte[]
21 MemoryStream ms = new MemoryStream();
22 bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
23 byte[] image = ms.ToArray()

//byte[]转Stream
Stream stream = new MemoryStream(bytes);

//Stream转byte[] 
byte[] bytes = new byte[stream.Length]; 
stream.Read(bytes, 0, bytes.Length); 
stream.Seek(0, SeekOrigin.Begin);  //设置当前流的位置为流的开始

//文件转byte[]
FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read); 
byte[] bytes = new byte[fileStream.Length]; 
fileStream.Read(bytes, 0, bytes.Length); 
fileStream.Close(); 

//byte[]写入文件
FileStream fs = new FileStream(fileName, FileMode.Create); 
BinaryWriter bw = new BinaryWriter(fs); 
bw.Write(bytes);
bw.Close(); 
fs.Close();