如何从.txt文件创建的列表中删除一行？

Question

I need to delete a line from a List created from a .txt file.

I have already made my list to be opened from a .txt file, I can see the list, I can add new client, and this client is being saved into the same .txt file, so next time I open it - I can see the "updated list".

public static void ShowClientList()
{
    string file =File.ReadAllText(@"C:\Users\Adminl\Documents\clients.txt");
    Console.WriteLine(file);
    Console.WriteLine();
}

public static void AddClient()
{
    Console.WriteLine("Civ");
    string civility = Console.ReadLine();                        
    Console.WriteLine("Name");
    string name = Console.ReadLine();                        
    Console.WriteLine("Surname");
    string surname = Console.ReadLine();                        
    Console.WriteLine("Age");
    string age = Console.ReadLine();                        
    Console.WriteLine("Telephone No");
    string telephone = Console.ReadLine();                       

    string appendText = civility +','+" "+ name + ',' + " " + surname + ',' + " " + age + ',' + " " + telephone + Environment.NewLine; // This text is always added, making the file longer over time if its not deleted

    string path = @"C:\Users\Adminl\Documents\clients.txt"; // FILE that either exist or no

    File.AppendAllText(path, appendText);
}

What I mean I have a .txt file with clients (Mr, John, Smith, 25, 777-00-666) and I would like to either delete this client from a list or delete\\update one of the parameters (for ex. telephone number, the last one). Thank you for the help!

Answer 1

我认为您最好将此文件反序列化为包含这些属性的对象列表，然后可以进行修改，最后可以再次将其持久化。

Answer 2

This is kind of tedious if you're just using a text file. But for the sake of the question:

You can use a StringBuilder to read all the contents from a file, do a split on commas (based on your format of (Mr, John, Smith, 25, 777-00-666) and skip that line when appending to the StringBuilder, and re-write the file.

public static RemoveClient(string firstName, string lastName)
{
  StringBuilder builder = new StringBuilder();
  foreach(var line in File.ReadAllLines(@"C:\Users\Adminl\Documents\clients.txt")
  {
    var split = line.Split(',', StringSplitOptions.RemoveEmptyEntries);
    if(split.Count < 3 || split[1] != firstName || split[2] != lastName) //|| any other comparisons you'd like to do
      builder.AppendLine(line);
  }

  using(var writer = new StreamWriter(@"C:\Users\Adminl\Documents\clients.txt"))
  {
    writer.Write(builder.ToString());
    writer.Flush();
  }
}