C#读写文件总结
1、使用FileStream讀寫文件
文件頭：
using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
讀文件核心代碼：
byte[] byData = new byte[100];
char[] charData = new char[1000];
try
{
FileStream sFile = new FileStream("文件路徑",FileMode.Open);
sFile.Seek(55, SeekOrigin.Begin);
sFile.Read(byData, 0, 100); //第一個(gè)參數(shù)是被傳進(jìn)來的字節(jié)數(shù)組,用以接受FileStream對(duì)象中的數(shù)據(jù),第2個(gè)參數(shù)是字節(jié)數(shù)組中開始寫入數(shù)據(jù)的位置,它通常是0,表示從數(shù)組的開端文件中向數(shù)組寫數(shù)據(jù),最后一個(gè)參數(shù)規(guī)定從文件讀多少字符.
}
catch (IOException e)
{
Console.WriteLine("An IO exception has been thrown!");
Console.WriteLine(e.ToString());
Console.ReadLine();
return;
}
Decoder d = Encoding.UTF8.GetDecoder();
d.GetChars(byData, 0, byData.Length, charData, 0);
Console.WriteLine(charData);
Console.ReadLine();
寫文件核心代碼：
FileStream fs = new FileStream(文件路徑,FileMode.Create);
//獲得字節(jié)數(shù)組
byte [] data =new UTF8Encoding().GetBytes(String);
//開始寫入
fs.Write(data,0,data.Length);
//清空緩沖區(qū)、關(guān)閉流
fs.Flush();
fs.Close();
2、使用StreamReader和StreamWriter
文件頭：
?
using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
StreamReader讀取文件：
StreamReader objReader = new StreamReader(文件路徑);
????? string sLine="";
????? ArrayList LineList = new ArrayList();???
????? while (sLine != null)
????? {
??????? sLine = objReader.ReadLine();
??????? if (sLine != null&&!sLine.Equals(""))
????????? LineList.Add(sLine);
????? }
??????????? objReader.Close();
??????????? return LineList;
StreamWriter寫文件：
? FileStream fs = new FileStream(文件路徑, FileMode.Create);
StreamWriter sw = new StreamWriter(fs);
//開始寫入
sw.Write(String);
//清空緩沖區(qū)
sw.Flush();
//關(guān)閉流
sw.Close();
fs.Close();
===================================================================================
方式一：用FileStream
//實(shí)例化一個(gè)保存文件對(duì)話框
??????????? SaveFileDialog sf = new SaveFileDialog();
??????????? //設(shè)置文件保存類型
??????????? sf.Filter = "txt文件|*.txt|所有文件|*.*";
??????????? //如果用戶沒有輸入擴(kuò)展名，自動(dòng)追加后綴
??????????? sf.AddExtension = true;
??????????? //設(shè)置標(biāo)題
??????????? sf.Title = "寫文件";
??????????? //如果用戶點(diǎn)擊了保存按鈕
??????????? if(sf.ShowDialog()==DialogResult.OK)
??????????? {
??????????????? //實(shí)例化一個(gè)文件流--->與寫入文件相關(guān)聯(lián)
??????????????? FileStream fs = new FileStream(sf.FileName,FileMode.Create);
??????????????? //獲得字節(jié)數(shù)組
byte [] data =new UTF8Encoding().GetBytes(this.textBox1.Text);
??????????????? //開始寫入
??????????????? fs.Write(data,0,data.Length);
??????????????? //清空緩沖區(qū)、關(guān)閉流
??????????????? fs.Flush();
??????????????? fs.Close();
??????????? }
方式二：用StreamWriter
//實(shí)例化一個(gè)保存文件對(duì)話框
??????????? SaveFileDialog sf = new SaveFileDialog();
??????????? //設(shè)置文件保存類型
??????????? sf.Filter = "txt文件|*.txt|所有文件|*.*";
??????????? //如果用戶沒有輸入擴(kuò)展名，自動(dòng)追加后綴
??????????? sf.AddExtension = true;
??????????? //設(shè)置標(biāo)題
??????????? sf.Title = "寫文件";
??????????? //如果用戶點(diǎn)擊了保存按鈕
??????????? if (sf.ShowDialog() == DialogResult.OK)
??????????? {
??????????????? //實(shí)例化一個(gè)文件流--->與寫入文件相關(guān)聯(lián)
??????????????? FileStream fs = new FileStream(sf.FileName, FileMode.Create);
??????????????? //實(shí)例化一個(gè)StreamWriter-->與fs相關(guān)聯(lián)
??????????????? StreamWriter sw = new StreamWriter(fs);
??????????????? //開始寫入
??????????????? sw.Write(this.textBox1.Text);
??????????????? //清空緩沖區(qū)
??????????????? sw.Flush();
??????????????? //關(guān)閉流
??????????????? sw.Close();
??????????????? fs.Close();
??????????? }
string FileName = Guid.NewGuid().ToString() + ".txt"; //GUID生成唯一文件名
??????? StringBuilder ckpw = new StringBuilder("\"憑證輸出\", \"V800\", \"001\", \"東風(fēng)隨州專用汽車有限公司\"," + "\"F89自由項(xiàng)16\", \"F90審核日期：\"");
??????? if (!FileIO.IsFolderExists(Server.MapPath("pzsc")))
??????????? FileIO.CreaterFolder(Server.MapPath(""), "file://pzsc/");
??????? string filePath = Server.MapPath("pzsc") + "\\" + FileName;
??????? System.IO.StreamWriter sw = new System.IO.StreamWriter(filePath, false, Encoding.GetEncoding("GB2312"));//創(chuàng)建的時(shí)候需要指定編碼格式，默認(rèn)是UTF-8，中文顯示亂碼
??????? sw.WriteLine(ckpw.ToString());
??????? sw.Close();
方式三：用BinaryWriter
//實(shí)例化一個(gè)保存文件對(duì)話框
??????????? SaveFileDialog sf = new SaveFileDialog();
??????????? //設(shè)置文件保存類型
??????????? sf.Filter = "txt文件|*.txt|所有文件|*.*";
??????????? //如果用戶沒有輸入擴(kuò)展名，自動(dòng)追加后綴
??????????? sf.AddExtension = true;
??????????? //設(shè)置標(biāo)題
??????????? sf.Title = "寫文件";
??????????? //如果用戶點(diǎn)擊了保存按鈕
??????????? if (sf.ShowDialog() == DialogResult.OK)
??????????? {
??????????????? //實(shí)例化一個(gè)文件流--->與寫入文件相關(guān)聯(lián)
??????????????? FileStream fs = new FileStream(sf.FileName, FileMode.Create);
??????????????? //實(shí)例化BinaryWriter
??????????????? BinaryWriter bw = new BinaryWriter(fs);
??????????????? bw.Write(this.textBox1.Text);
??????????????? //清空緩沖區(qū)
??????????????? bw.Flush();
??????????????? //關(guān)閉流
??????????????? bw.Close();
??????????????? fs.Close();
??????????? }
C#緩存流示例------>用緩存流復(fù)制文件
C#文件處理操作必須先導(dǎo)入命名空間：using System.IO;
背景：使用VS2005、一個(gè)按鈕、一個(gè)窗體、C#緩存流、把D:\KuGoo\愛得太多.wma復(fù)制到D:\并更名為love.wma,即：D:\love.wma
在按鈕的Click事件中添加如下代碼：
private void button1_Click(object sender, EventArgs e)
??????? {
??????????? //創(chuàng)建兩個(gè)文件流 一個(gè)是源文件相關(guān)，另一個(gè)是要寫入的文件
??????????? FileStream fs = new FileStream(@"D:\KuGoo\愛得太多.wma",FileMode.Open);
??????????? FileStream fs2 = new FileStream(@"D:\love.wma",FileMode.Create);
??????????? //創(chuàng)建一個(gè)字節(jié)數(shù)組，作為兩者之間的媒介
??????????? //好比兩個(gè)人拿蘋果，這個(gè)字節(jié)數(shù)組就好比一個(gè)籃子，一個(gè)人作死的把蘋果送到籃子里面，
??????????? //而我就可以作死得拿蘋果，通過這個(gè)媒介我們互不干擾，
??????????? //不需要互相等待【她往籃子里面放了蘋果我才可以去拿】，提高了效率
byte[] data = new byte[1024];
??????????? //創(chuàng)建兩個(gè)緩沖流，與兩個(gè)文件流相關(guān)聯(lián)
??????????? BufferedStream bs = new BufferedStream(fs);
??????????? BufferedStream bs2= new BufferedStream(fs2);
??????????? //fs作死的讀，fs2作死的寫，直到fs沒有字節(jié)可讀fs2就不寫了
?????????? //好比，一個(gè)人作死的往籃子里面丟蘋果，另一個(gè)人作死得往籃子里面拿蘋果，直到籃子里面沒有蘋果拿了為止
??????????? //即-->那個(gè)人沒有蘋果往籃子里面放了
??????????? while(fs.Read(data,0,data.Length)>0)
??????????? {
??????????????? fs2.Write(data,0,data.Length);
??????????????? fs2.Flush();
??????????? }
??????????? //關(guān)閉流，好比兩個(gè)人累了，都要休息 呵呵o(∩_∩)o...
??????????? fs.Close();
??????????? fs2.Close();
??????? }
C#內(nèi)存流示例----->用內(nèi)存流來讀取圖片
C#文件處理操作必須先導(dǎo)入命名空間：using System.IO;
背景：一個(gè)窗體、一個(gè)pictureBox、一個(gè)lable[沒有選擇圖片,lable的text為"圖片未選擇"],在pictureBox1的Click事件中添加如下代碼：
private void pictureBox1_Click(object sender, EventArgs e)
??????? {
??????????? //實(shí)例化一個(gè)打開文件對(duì)話框
??????????? OpenFileDialog op = new OpenFileDialog();
??????????? //設(shè)置文件的類型
??????????? op.Filter = "JPG圖片|*.jpg|GIF圖片|*.gif";
??????????? //如果用戶點(diǎn)擊了打開按鈕、選擇了正確的圖片路徑則進(jìn)行如下操作：
??????????? if(op.ShowDialog()==DialogResult.OK)
??????????? {
??????????????? //清空文本
??????????????? this.label1.Text = "";
??????????????? //實(shí)例化一個(gè)文件流
??????????????? FileStream fs = new FileStream(op.FileName, FileMode.Open);
??????????????? //把文件讀取到字節(jié)數(shù)組
byte[] data = new byte[fs.Length];
??????????????? fs.Read(data, 0, data.Length);
??????????????? fs.Close();
??????????????? //實(shí)例化一個(gè)內(nèi)存流--->把從文件流中讀取的內(nèi)容[字節(jié)數(shù)組]放到內(nèi)存流中去
??????????????? MemoryStream ms = new MemoryStream(data);
??????????????? //設(shè)置圖片框 pictureBox1中的圖片
??????????????? this.pictureBox1.Image = Image.FromStream(ms);
??????????? }
??????? }
轉(zhuǎn)載于:https://www.cnblogs.com/wwwzzg168/p/3572105.html
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