如何使用Stream Reader C＃逐行正确读取文件

Question

How can read text from a file line by line?

This code who I used is read first and second line in first rotation. The following isn't working as it's returning two different strings in method sr.ReadLine() . Does the ReadLine() method take the next line from file rather than the current line?

List<string> allInformation = new List<string>();
DateTime minimumDateTime = times[this.Step].AddMinutes(-different);
DateTime maximumDateTime = times[this.Step].AddMinutes(different);

using (FileStream fs = System.IO.File.Open(this.File, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
using (BufferedStream bs = new BufferedStream(fs))
using (StreamReader sr = new StreamReader(bs))
{
    DateTime thisTime;
    string[] info = new string[6];

    while (sr.Peek() >= 0)
    {
        info = sr.ReadLine().Split(new string[] { ", ", ",", "\"" }, StringSplitOptions.RemoveEmptyEntries);
        thisTime = DateTime.ParseExact(info[FileConstants.DATE], "yyyy-M-d H:m:s", null);

        if (thisTime > minimumDateTime && thisTime < maximumDateTime)
        {
            allInformation.Add(sr.ReadLine());
        }
    }
}

Answer 1

You are using ReadLine two times in the loop. Store the return value of StreamReader.ReadLine in a string variable. Otherwise you are advancing the reader to the next line.

while (sr.Peek() >= 0)
{
    string line = sr.ReadLine();
    info = line.Split(new string[] { ", ", ",", "\"" }, StringSplitOptions.RemoveEmptyEntries);
    thisTime = DateTime.ParseExact(info[FileConstants.DATE], "yyyy-M-d H:m:s", null);

    if (thisTime > minimumDateTime && thisTime < maximumDateTime)
    {
        allInformation.Add(line);
    }
}

Answer 2

I know you already have the answer, but I just wanted to point out that you can write that entire method more succinctly using Linq like this:

var minimumDateTime = times[this.Step].AddMinutes(-different);
var maximumDateTime = times[this.Step].AddMinutes(different);

var linesInDateRange = 
    from   line in System.IO.File.ReadLines(this.File)
    let    info = line.Split(new[] {", ", ",", "\""}, StringSplitOptions.RemoveEmptyEntries)
    let    thisTime = DateTime.ParseExact(info[FileConstants.DATE], "yyyy-M-d H:m:s", null)
    where  thisTime > minimumDateTime && thisTime < maximumDateTime
    select line;

var allInformation = linesInDateRange.ToList();