C#逐行读取文本文件并编辑特定行

Question

我想逐行读取文本文件并编辑特定行。所以，我将文本文件放入一个字符串变量中，如：

string textFile = File.ReadAllText(filename);

我的文本文件是这样的：

Line A
Line B
Line C
Line abc
Line 1
Line 2
Line 3

我有一个特定的字符串 (="abc")，我想在此文本文件中搜索它。所以，我正在阅读这些行，直到找到字符串并转到第三行（"Line 3" - >这一行总是不同的）找到字符串之后：

string line = "";
string stringToSearch = "abc";

using (StringReader reader = new StringReader(textFile))
{
    while ((line = reader.ReadLine()) != null)
    {
        if (line.Contains(stringToSearch))
        {
            line = reader.ReadLine();
            line = reader.ReadLine();
            line = reader.ReadLine();

            //line should be cleared and put another string to this line.
        }
    }
}

我想清除读取的第三行并将另一个字符串放入该行并将整个 string 保存到 textFile.

我该怎么做？

Answer 1

重新写入整个文件会更容易：

string old  = "abc";
string nw   = "aa";
int counter = 0;

using(StreamWriter w = new StreamWriter("newfile")
{
    foreach(string s in File.ReadLines(path))
        w.WriteLine(s == old ? nw : s);
}

Answer 2

您可能需要如下内容：

DirectoryInfo di = new DirectoryInfo(Location);
FileInfo[] rgFiles = di.GetFiles("txt File");

foreach (FileInfo fi in rgFiles)
{
    string[] alllines = File.ReadAllLines(fi.FullName);

    for (int i = 0; i < alllines.Length; i++)
    {
        if (alllines[i].Contains(stringToSearch))
        {                        
            alllines[i] = alllines[i].Replace(stringToSearch, some value );
        }
    }
}

这样您将逐行阅读文本文件，直到文档结束，如果值被拾取，它将被替换为您的新值。

Answer 3

您可以像这样将内容存储在 StringBuilder 中：

StringBuilder sbText = new StringBuilder();
using (var reader = new System.IO.StreamReader(textFile)) {
    while ((line = reader.ReadLine()) != null) {
        if (line.Contains(stringToSearch)) {
            //possibly better to do this in a loop
            sbText.AppendLine(reader.ReadLine());
            sbText.AppendLine(reader.ReadLine());

            sbText.AppendLine("Your Text");
            break;//I'm not really sure if you want to break out of the loop here...
        }else {
            sbText.AppendLine(line);
        }
    }
}

然后像这样写回去：

using(var writer = new System.IO.StreamWriter(@"link\to\your\file.txt")) {
    writer.Write(sbText.ToString());
}

或者，如果您只是想将其存储在字符串 textFile 中，您可以这样做：

textFile = sbText.ToString();

Answer 4

这是一个完整的例子：

using System;
using System.IO;

namespace rename
{
    class Program
    {
        static void Main(string[] args)
        {
            // Fix files, replace text
            DirectoryInfo di = new DirectoryInfo(@"C:\temp\all\");
            FileInfo[] rgFiles = di.GetFiles("*");

            foreach (FileInfo fi in rgFiles)
            {
                string[] alllines = File.ReadAllLines(fi.FullName);

                for (int i = 0; i < alllines.Length; i++)
                {
                    if (alllines[i].StartsWith("00:"))
                    {
                        // Edit: Replace these lines with an empty line
                        alllines[i] = alllines[i].Replace(alllines[i], "");
                    }
                }

                // Rewrite new files in the folder
                File.WriteAllLines(@"C:\temp\new\" + fi.Name, alllines);
            }
        }
    }
}

C#逐行读取文本文件并编辑特定行

C# Read text file line by line and edit specific line

c#

string

stringwriter

stringreader