C# 文件操作

Question

文件操作

文件名处理

//替换掉非法字符
fileName = fileName.Replace(":", "_").Replace(" ", "_").Replace("\\", "_").Replace("/", "_");

获取目录下所有文件的文件名

String path = @"X:\xxx\xxx";

//第一种方法
var files = Directory.GetFiles(path, "*.txt");

foreach (var file in files)
    Console.WriteLine(file);

//第二种方法
DirectoryInfo folder = new DirectoryInfo(path);

foreach (FileInfo file in folder.GetFiles("*.txt"))
{
    Console.WriteLine(file.FullName);
}

C#判断文件和目录是否存在，不存在则创建

文件：
if (File.Exists(Server.MapPath("~/upimg/Data.html"))){
   File.Create(MapPath("~/upimg/Data.html"));//创建该文件
}

文件夹：
if (!Directory.Exists(Server.MapPath("~/upimg/hufu"))){
   Directory.CreateDirectory(Server.MapPath("~/upimg/hufu"));
}

删除文件

/// <summary>
/// 删除单个文件
/// </summary>
/// <param name="_filepath">文件相对路径</param>
public static bool DeleteFile(string _filepath)
{
   if (string.IsNullOrEmpty(_filepath))
   {
       return false;
   }
   string fullpath = GetMapPath(_filepath);
   if (File.Exists(fullpath))
   {
       File.Delete(fullpath);
       return true;
   }
   return false;
}
/// <summary>
/// 删除上传的文件（及缩略图)
/// </summary>
/// <param name="_filepath"></param>
public static void DeleteUpFile(string _filepath)
{
    if (string.IsNullOrEmpty(_filepath))
    {
        return;
    }
    string thumbnailpath = _filepath.Substring(0, _filepath.LastIndexOf("/")) + "mall_" + _filepath.Substring(_filepath.LastIndexOf("/") + 1);
    string fullTPATH = GetMapPath(_filepath); //宿略图
    string fullpath = GetMapPath(_filepath); //原图
    if (File.Exists(fullpath))
    {
        File.Delete(fullpath);
    }
    if (File.Exists(fullTPATH))
    {
        File.Delete(fullTPATH);
    }
}

返回文件大小 KB

/// <summary>
/// 返回文件大小 KB
/// </summary>
/// <param name="_filepath">文件相对路径</param>
/// <returns>int</returns>
public static int GetFileSize(string _filepath)
{
    if (string.IsNullOrEmpty(_filepath))
    {
        return 0;
    }
    string fullpath = GetMapPath(_filepath);
    if (File.Exists(fullpath))
    {
        FileInfo fileInfo = new FileInfo(fullpath);
        return ((int)fileInfo.Length) / 1024;
    }
    return 0;
}

返回文件扩展名，不含“.”

/// <summary>
/// 返回文件扩展名，不含“.”
/// </summary>
/// <param name="_filepath">文件全名称</param>
/// <returns>string</returns>
public static string GetFileExt(string _filepath)
{
    if (string.IsNullOrEmpty(_filepath))
    {
        return "";
    }
    if (_filepath.LastIndexOf(".") > 0)
    {
        return _filepath.Substring(_filepath.LastIndexOf(".") + 1); //文件扩展名，不含“.”
    }
    return "";
}

文件下载

TransmitFile 方式

/* 微软为 Response 对象提供了一个新的方法 TransmitFile 来解决使用 Response.BinaryWrite 下载超过 400MB 的文件时，
导致 Aspnet_wp.exe 进程回收而无法成功下载的问题。 代码如下：*/
Response.ContentType = "application/x-zip-compressed";  
string FileName = "test.doc";  
//使用 UTF-8 对文件名进行编码  
Response.AppendHeader("Content-Disposition", "attachment;filename=\"" + HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8) + "\"");  
Response.ContentType = "application/octet-stream";  
Response.AddHeader("Content-Disposition", "attachment;filename=" + FileName);  
string filename = Server.MapPath("../ReportTemplate/test.doc");  
Response.TransmitFile(filename);  

WriteFile 方式

/* 
using System.IO;          
*/
string fileName = "test.doc";//客户端保存的文件名  
string filePath = Server.MapPath("../ReportTemplate/test.doc");//路径  
FileInfo fileInfo = new FileInfo(filePath);  
Response.Clear();  
Response.ClearContent();  
Response.ClearHeaders();  
Response.AddHeader("Content-Disposition", "attachment;filename=\"" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8) + "\"");  
Response.AddHeader("Content-Length", fileInfo.Length.ToString());  
Response.AddHeader("Content-Transfer-Encoding", "binary");  
Response.ContentType = "application/octet-stream";  
Response.WriteFile(fileInfo.FullName);  
Response.Flush();  
Response.End();  

WriteFile 分块下载方式

string fileName = "test.doc";//客户端保存的文件名  
string filePath = Server.MapPath("../ReportTemplate/test.doc");//路径

System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath);

if (fileInfo.Exists == true)  
{  
    const long ChunkSize = 102400; //100K 每次读取文件，只读取 100K，这样可以缓解服务器的压力  
    byte[] buffer = new byte[ChunkSize];  

    Response.Clear();  
    System.IO.FileStream iStream = System.IO.File.OpenRead(filePath);  
    long dataLengthToRead = iStream.Length; //获取下载的文件总大小  
    Response.ContentType = "application/octet-stream";  
    Response.AddHeader("Content-Disposition",  
    "attachment; filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));  
    while (dataLengthToRead > 0 && Response.IsClientConnected)  
    {  
        int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize)); //读取的大小  
        Response.OutputStream.Write(buffer, 0, lengthRead);  
        Response.Flush();  
        dataLengthToRead = dataLengthToRead - lengthRead;  
    }  
    Response.Close();  
}  

流方式下载

string fileName = "test.doc";//客户端保存的文件名  
string filePath = Server.MapPath("../ReportTemplate/test.doc");//路径

//以字符流的形式下载文件 
FileStream fs = new FileStream(filePath, FileMode.Open);  
byte[] bytes = new byte[(int)fs.Length];  
fs.Read(bytes, 0, bytes.Length);  
fs.Close();  
Response.ContentType = "application/octet-stream";  
//通知浏览器下载文件而不是打开  
Response.AddHeader("Content-Disposition", "attachment;  filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));  
Response.BinaryWrite(bytes);  
Response.Flush();  
Response.End();