read text file chunks by chunks by scrollbar [closed]

问题

Hi i have read this question :

Reading very large text files, should I be incorporating async?

I diged the net especially the STACK OVERFLOW !

The results was 14 method to do this but none of them is not complete !

In 2 last days , i am working on this and tested and benchmarked 14 methods.

for example :

        private void method()
        {

        FileStream FS = new FileStream(path, FileMode.Open, FileAccess.ReadWrite);

        int FSBytes = (int) FS.Length;

        int ChunkSize = 24;

        byte[] B = new byte[ChunkSize];

        int Pos;

        for (Pos = 0; Pos < (FSBytes - ChunkSize); Pos += ChunkSize)

        {

        FS.Read(B,0 , ChunkSize);
        string content = System.Text.Encoding.Default.GetString(B);

        richTextBox1.Text=content=;


        }

        B = new byte[FSBytes - Pos];

        FS.Read(B,0, FSBytes - Pos);
        string content2 = System.Text.Encoding.Default.GetString(B);

        richTextBox1Text=content2;


        FS.Close(); 
        FS.Dispose();
        }

for 5mb text file , it takes too long , what should i do ?

回答1:

This is a working example of reading a text file per stream to accomplish what you are trying to do. I have tested it with a 100 MB text file, and it worked well, but you have to see if larger files work as well.

This is the example. Just bring a RichTextBox to your form and a VScrollBar. Then use a file 'test.txt' on your hard drive 'C:'.

public partial class Form1 : Form
{
    const int PAGE_SIZE = 64;   // in characters
    int position = 0;  // position in stream

    public Form1()
    {
        InitializeComponent();
    }

    private void vScrollBar1_Scroll(object sender, ScrollEventArgs e)
    {
        position = e.NewValue * PAGE_SIZE;

        ReadFile(position);    
    }

    private void ReadFile(int position)
    {
        using (StreamReader sr = new StreamReader(@"C:\test.txt"))
        {
            char[] chars = new char[PAGE_SIZE];
            sr.BaseStream.Seek(position, SeekOrigin.Begin);
            sr.Read(chars, 0, PAGE_SIZE);

            string text = new string(chars);
            richTextBox1.Text = text;
        }    
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        ReadFile(position);
    }
}

来源：https://stackoverflow.com/questions/18113513/read-text-file-chunks-by-chunks-by-scrollbar

标签

winforms

textbox

chunks