c# Stream to File的知识点

个人倾向使用File.WriteAllByte写入文件：

//Stream to File
MemoryStream ms=...Stream;
ms.Position = 0;
byte[] buffer = new byte[ms.Length];
ms.Read(buffer, 0, (int)ms.Length);
File.WriteAllBytes(filepath, buffer);//写入文件

StreamRead,StreamWrite,SreamRead,以及File的部分操作

// StreamRead,StreamWrite,File只能操作文本文件 
//FileStream可以操作所有格式 包括文本，文件，图片，视频  
//SreamRead读取文件  
using (StreamReader reader = new StreamReader(filepath))  
 {  
        //reader.ReadLine();读取第一行  
        string data = reader.ReadToEnd();//读取所有  
 }  
//StreamWrite写入文件  
 using (StreamWriter writer = new StreamWriter(filepath))  
 {  
         //writer.Write("写入的内容");  
         //也可以如下面一行一行写入  
         writer.WriteLine("0");  
         writer.WriteLine("1");  
         writer.WriteLine(picName);  
         writer.WriteLine(txtCount.Text);  
 }  
  
//File即可以读取文本 也可以写入文本   
//读取  
string data = File.ReadAllText(filepath);
string[] datas = File.ReadAllLines(filepath);
//写入   
string[] ss = new string[] {"arr1","arr2" };
File.WriteAllLines(filepath, ss);   
File.WriteAllText(filepath, "
换行
"); 
//附加
File.AppendAllLines(filepath,ss);
File.AppendAllText(filepath,str); 
  
//FileStream可以操作所有格式 包括文本，文件，图片，视频  
//FileStream读取  
string ss = null;
byte[] buffer = new byte[1024 * 1024 * 1];  //针对大文件1M1M的读取
 using (FileStream sr = new FileStream(sfilepath, FileMode.OpenOrCreate, FileAccess.Read))  
 {  
    int sss = sr.Read(buffer, 0, buffer.Length);
    ss = Encoding.Default.GetString(buffer, 0, sss);  
 }   
//FileStream写入   
using (FileStream fsWrite = new FileStream(filepath, FileMode.OpenOrCreate, FileAccess.Write))  
{   
    byte[] buffer = Encoding.Default.GetBytes(str);
    fsWrite.Write(buffer, 0, buffer.Length);  
}

Stream 和 File 之间的转换

/// <summary>   
/// 将 Stream 写入文件   
/// </summary>   
public void StreamToFile(Stream stream,string filepath)   
{   
    // 把 Stream 转换成 byte[]   
    byte[] bytes = new byte[stream.Length];   
    stream.Read(bytes, 0, bytes.Length);   
    // 设置当前流的位置为流的开始   
    stream.Seek(0, SeekOrigin.Begin);  
    // 把 byte[] 写入文件   
    FileStream fs = new FileStream(filepath, FileMode.Create);   
    BinaryWriter bw = new BinaryWriter(fs);   
    bw.Write(bytes);   
    bw.Close();   
    fs.Close();   
}  
/// <summary>   
/// 从文件读取 Stream   
/// </summary>   
public Stream FileToStream(string filepath)   
{               
    // 打开文件   
    FileStream fileStream = new FileStream(filepath, FileMode.Open, FileAccess.Read, FileShare.Read);   
    // 读取文件的 byte[]   
    byte[] bytes = new byte[fileStream.Length];   
    fileStream.Read(bytes, 0, bytes.Length);   
    fileStream.Close();   
    // 把 byte[] 转换成 Stream   
    Stream stream = new MemoryStream(bytes);   
    return stream;   
}  

文件复制（当然File.Copy更常用，这个是偶然中使用到整理的）

public static void CopyFile(string soucre, string target)  
        {  
            //读取的流  
            using (FileStream fsRead = new FileStream(soucre, FileMode.Open, FileAccess.Read))  
            {  
                //写入的流  
                using (FileStream fsWrite = new FileStream(target, FileMode.OpenOrCreate, FileAccess.Write))  
                {  
                    byte[] buffer = new byte[1024 * 1024 * 5];  
                    while (true)  
                    {   
                        int r = fsRead.Read(buffer, 0, buffer.Length);  
                        //0代表已经读取完  
                        if (r == 0)  
                        {  
                            break;  
                        }  
                        fsWrite.Write(buffer, 0, r);  
                    }  
                }  
            }  
        }