c#读取大容量txt文件怎么才能不卡

Question

多线程 //例子
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Threading;namespace MultiThread
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            using (FolderBrowserDialog fbd = new FolderBrowserDialog())
            {
                fbd.Description = "选择要多线程读取文件的路径";
                fbd.ShowNewFolderButton = false;
                if (fbd.ShowDialog(this) == DialogResult.OK)
                {
                    DirectoryInfo di = new DirectoryInfo(fbd.SelectedPath);
                    foreach (FileInfo fi in di.GetFiles("*.txt"))
                    {
                        Thread t = new Thread(this.InvokeThread);
                        t.Start(fi.FullName);
                    }
                }
            }
        }
        private delegate void ReadFile(object filePath);
        private void InvokeThread(object filePath)
        {
            if (this.InvokeRequired)
            {
                this.Invoke(new ReadFile(ReadFileContent), filePath);
            }
            else
            {
                ReadFileContent(filePath);
            }
        }
        private void ReadFileContent(object filePath)
        {
            this.textBox1.AppendText(File.ReadAllText(filePath.ToString(), Encoding.Default));
            this.textBox1.AppendText("\r\n");
        }
    }
}

Answer 1

用线程异步调用可以实现。
  
 public delegate void Callback(string str);
//.....class  
    private void Readfile(object filepath)
        {
            if (textBox2.InvokeRequired)
            {
               Callback call = new Callback(Readfile);
               this.BeginInvoke(call,new object[]{filepath});//异步执行
            }
            else
            {
                this.textBox2.AppendText(File.ReadAllText(filepath.ToString(), Encoding.Default));
                this.textBox2.AppendText("\r\n");
            }
        }
        private void button1_Click(object sender, EventArgs e)
        {            using (OpenFileDialog fbd = new OpenFileDialog())
            {
                fbd.Filter = "(*.*)|*.txt";
                if (fbd.ShowDialog(this) == DialogResult.OK)
                {
                    Thread t = new Thread(new ParameterizedThreadStart(Readfile));//开启线程
                    t.Start(fbd.FileName);
                }
            }
}

Answer 2

 正确的方法出来了。        private void button1_Click(object sender, EventArgs e)
        {
            const long ChunkSize = 102400;//100K 每次读取文件，只读取100K 
            using (OpenFileDialog fbd = new OpenFileDialog())
            {
                fbd.Filter = "(*.*)|*.txt";
                if (fbd.ShowDialog(this) == DialogResult.OK)
                {
                    byte[] bytcontent = new byte[ChunkSize];
                    FileStream fs = new FileStream(fbd.FileName,FileMode.Open);
                    long dataLengthToRead = fs.Length;//获取下载的文件总大小                   while (dataLengthToRead > 0)
                   {     
                        int lengthRead = fs.Read(bytcontent, 0, Convert.ToInt32(ChunkSize));//读取的大小
                        Thread t = new Thread(new ParameterizedThreadStart(Readfile));
                        t.Start(System.Text.Encoding.Default.GetString(bytcontent));
                        dataLengthToRead -= lengthRead;
                    }
                }
            }}
public delegate void Callback(string str);        private void Readfile(object content)
        {
            if (richTextBox1.InvokeRequired)
            {
                Callback call = new Callback(Readfile);
                this.BeginInvoke(call, new object[] { content });
            }
            else
            {
                this.richTextBox1.AppendText(content.ToString());
                this.richTextBox1.AppendText("\r\n");
            }
        }