文本文件:逐行读取C# [英] text file: Reading line by line C#

问题描述

所以，假设我有一个20行的文本文件，每行文本不同.我希望能够有一个包含第一行的字符串，但是当我执行NextLine()时；我希望它成为下一行.我试过了，但似乎不起作用:

So, let's say i have a text file with 20 lines, with on each line different text. i want to be able to have a string that has the first line in it, but when i do NextLine(); i want it to be the next line. I tried this but it doesn't seem to work:

string CurrentLine; 
int LastLineNumber;   
Void NextLine() 
{
     System.IO.StreamReader file = new System.IO.StreamReader("c:\\test.txt");
     CurrentLine = file.ReadLine(LastLineNumber + 1);
     LastLineNumber++;
}

我该怎么做?预先感谢.

How would i be able to do this? Thanks in advance.

推荐答案

通常，最好以某种方式设计此方式以使文件保持打开状态，而不是每次都尝试重新打开该文件.

In general, it would be better if you could design this in a way to leave your file open, and not try to reopen the file each time.

如果这不切实际，则需要多次调用 ReadLine :

If that is not practical, you'll need to call ReadLine multiple times:

string CurrentLine; 
int LastLineNumber;   
void NextLine() 
{
    // using will make sure the file is closed
    using(System.IO.StreamReader file = new System.IO.StreamReader("c:\\test.txt"))
    {
        // Skip lines
        for (int i=0;i<LastLineNumber;++i)
            file.ReadLine();

        // Store your line
        CurrentLine = file.ReadLine();
        LastLineNumber++;
    }
}

请注意，这可以通过 File.ReadLines 进行简化:

Note that this can be simplified via File.ReadLines:

void NextLine() 
{
    var lines = File.ReadLines("C:\\test.txt");

    CurrentLine = lines.Skip(LastLineNumber).First();
    LastLineNumber++;
}

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