如何检查在文本文件中找到字符串的位置

本文关键字：字符串 位置 文件 文本 何检查 检查 | 更新日期: 2023-09-27 17:49:28

编辑:修复:)谢谢!

我想做一个登录代码，我在登录功能上遇到了一点麻烦。我需要检查哪一行用户名位于，在一个文本文件。这可能吗?如果没有，有没有别的办法?

编辑:添加代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1
{
class Program
{
    static void Main(string[] args)
    {
        int loginAttempt = 0;
        using (System.IO.StreamWriter file = new System.IO.StreamWriter("C:''Users''Public''Usernames.txt", true))
        {
            file.WriteLine();
        }
        int userType = 0;
        string retrievedUsername = String.Empty;
        using (System.IO.StreamReader fileUsername = new System.IO.StreamReader("C:''Users''Public''Usernames.txt"))
        {
            retrievedUsername = fileUsername.ReadToEnd();
        }

        Console.ForegroundColor = ConsoleColor.Magenta;
            Console.WriteLine("Please note that this is a prototype, passwords are not hashed/encrypted ^_^. Report any bugs / flaws with this to andrew.yu6@hotmail.com, If I get any spam I will high five you in the face with a chair");
            Console.ForegroundColor = ConsoleColor.Green; 
        Console.WriteLine("Welcome to the meData service! Ver. 0.01 Beta, made by mechron");
        do
        {
            Console.WriteLine("Please enter login below or type register to register a new account on this device");
            string loginUsername = Console.ReadLine();
            if (loginUsername == "login")
            {
                Console.WriteLine("Type in your username");
                string loginUser = Console.ReadLine();
            }
            else
            {
                if (loginUsername == "register")
                {
                    int registerAttempt = 0;
                    Console.WriteLine("Choose your username!");
                    string registerUsername = Console.ReadLine();
                    bool containUser = System.IO.File.ReadAllLines("C:''Users''Public''Usernames.txt").Contains(registerUsername);
                    if (containUser == true) { Console.WriteLine("Error, username already exists! Please try again!"); } else { registerAttempt = 1; }

                    if( registerAttempt == 1 ) 
                   {
                    using (System.IO.StreamWriter files = new System.IO.StreamWriter("C:''Users''Public''Usernames.txt", true))
                    {
                        files.WriteLine(registerUsername);
                    }
                   }
                    if (registerAttempt == 1)
                    {
                        Console.WriteLine("Now choose your password!");
                        string loginPass = Console.ReadLine();
                        using (System.IO.StreamWriter files = new System.IO.StreamWriter("C:''Users''Public''Passwords.txt", true))
                        {
                            files.WriteLine(loginPass);
                        }
                        Console.WriteLine("Good! Now you will be returned to the start screen! Try to login there!");
                    }
                }
                else
                {
                    Console.WriteLine("Error, command not recognized. Try again");
                }

            }
        } while ( loginAttempt == 0 );

如何检查在文本文件中找到字符串的位置

Try This:

if(loginUsername == "login")
{
  Console.WriteLine("Type in your username");
  string loginUser = Console.ReadLine();
  int lineCount=1;
  foreach(var line in File.ReadLines("LoginFile.txt"))
  {
    if(line.Contains(loginUser))
    {
       Console.WriteLine("UserName found in Line No = "+ lineCount);
       break;
    }
       lineCOunt++;
  }
}

我假设您对这行代码感兴趣:

bool containUser = System.IO.File.ReadAllLines("C:''Users''Public''Usernames.txt").Contains(registerUsername);

不，这不会告诉你行号。你必须自己用循环来做。

string[] lines = System.IO.File.ReadAllLines("C:''Users''Public''Usernames.txt")
int line_number= 0;
for(;line_number< lines.Length; line_number++)
{
    if(lines[line_number] == registeredUser)
        break;
}
//Your line number is now contained in line_number
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