文件处理

一丶删除文件

 public string DelFile(string fileRelativePath)
        {

            try
            {
                string filePath = Server.MapPath("~" + fileRelativePath);

                //if (System.IO.File.Exists(filePath))
                //{
                //    System.IO.File.Delete(filePath);
                //}

                FileInfo file = new FileInfo(filePath);
                if (file.Exists)
                {
                    file.Delete();
                }

                return "";
            }
            catch (Exception)
            {

                throw;
            }
        }

 eg1:

    try
    {
        string item_url = Server.MapPath(FileUrl);
        FileInfo fileInfo = new FileInfo(item_url);
        if (fileInfo.Exists)
        {
            fileInfo.Delete();
        }
    }
    catch (Exception)
    {
        throw;
    }

 文件流

方法：

public override int Read(byte[] array, int offset, int count);
public override void Write(byte[] array, int offset, int count);
Dispose()：释放由 Stream 使用的所有资源
Close()关闭当前流并释放与之关联的所有资源（如套接字和文件句柄）。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;    //FileStream类的命名空间
namespace Filestream读写文件
{
    class Program
    {
        static void Main(string[] args)
        {
            //FileStream 操作字节的
            //1.创建FileStream类对象
            FileStream fsread = new FileStream(@"F:C#projectsabc.txt",FileMode.OpenOrCreate,FileAccess.Read);
            byte[] buffer=new byte[1024*1024*2];    //定义一个2M的字节数组
            //返回本次实际读取到的有效字节数
            int r=fsread.Read(buffer,0,buffer.Length);    //每次读取2M放到字节数组里面
            //将字节数组中每一个元素按照指定的编码格式解码成字符串
            string s=Encoding.Default.GetString(buffer,0,r);    
            //关闭流
            fsread.Close();
            //释放流所占用的资源
            fsread.Dispose();
            Console.WriteLine(s);  //打印读取到的内容
            Console.ReadKey();
        }
    }
}

1. byte[] 和 Stream

/// <summary>
/// byte[]转换成Stream
/// </summary>
/// <param name="bytes"></param>
/// <returns></returns>
public Stream BytesToStream(byte[] bytes)
{
    Stream stream = new MemoryStream(bytes);
    return stream;
}
 
/// <summary>
/// Stream转换成byte[]
/// </summary>
/// <param name="stream"></param>
/// <returns></returns>
public byte[] StreamToBytes(Stream stream)
{
    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
    return bytes;
}

2.文件 和 Stream

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