i want to check if entered string is a Integer or not for example
12 = True
+12 = True
-5 = True
4.4 = False
4as = False
I make it using int.TryParse but what I want is to using ASCII without using int.TryParse
string str;
int strint;
int strintoA;
bool flag = false;
while (flag == false)
{
Console.Write("Enter a Number : ");
str = Console.ReadLine();
flag = int.TryParse(str, out strint);
if (flag == false)
{
Console.WriteLine("Please Enter Numbers Only.");
}
else
{
strintoA = strint;
Console.WriteLine("Entered String: " + str + " is a Number!" );
break;
}
}
Console.ReadKey();
You could also use regular expressions:
var regex = new Regex(#"^[-+]?\d+$");
var str = Console.ReadLine();
if (regex.IsMatch(str))
{
Console.WriteLine($"{str} is a number!");
}
check the first char for -|+|digit, check rest isDigit
for (int i = 0; i < str.Length; i++)
{
var c = str[i];
if (i == 0)
{
if (!(c == '+' || c == '-' || char.IsDigit(c)) {
return false;
}
}
if (!char.IsDigit(c)) return false;
}
return true;
why dont use:
if(intString[0] == '+' || intString[0] == '-') intString = intString.Substring(1, intString.Length - 1);
bool isNumber = intString.All(char.IsDigit);
Not sure why you don't want to use int.TryParse but the following code should do:
static bool IsValidInteger(string s)
{
var leadingSignSeen = false;
var digitSeen = false;
var toParse = s.Trim();
foreach (var c in toParse)
{
if (c == ' ')
{
if (digitSeen)
return false;
}
else if (c == '+' || c == '-')
{
if (leadingSignSeen || digitSeen)
return false;
leadingSignSeen = true;
}
else if (!char.IsDigit(c))
return false;
else
{
digitSeen = true;
}
}
return true;
}
This will accept any integer with leading sign and leading and trailing spaces. Whitespaces between leading sign and digits are also accepted.
FYI: You can refactor your code to simplify it for exactly the same functional output:
void Main()
{
int result;
Console.Write("Enter a Number : ");
while (!int.TryParse(Console.ReadLine(), out result))
{
Console.WriteLine("Please Enter Numbers Only.");
Console.Write("Enter a Number : ");
}
Console.WriteLine($"Entered String: {result} is a Number!");
Console.ReadKey();
}
If you have a good reason to not use int.TryParse (e.g. it's lacking some functionality, or this is an exercise where you've been asked to write your own) you could use the above replacing int.TryParse with a call to IsNumericCustom, assuming the below signature (or change type int to whatever data type you need to handle).
public bool IsNumericCustom(string input, out int output)
{
//...
}
Or if you only care about whether the value's numeric and not the parsed value:
void Main()
{
string result;
Console.Write("Enter a Number : ");
//while (!int.TryParse((result = Console.ReadLine()), out _))
while (!IsNumericCustom((result = Console.ReadLine()))
{
Console.WriteLine("Please Enter Numbers Only.");
Console.Write("Enter a Number : ");
}
Console.WriteLine($"Entered String: {result} is a Number!");
Console.ReadKey();
}
public bool IsNumericCustom(string input)
{
//...
}
As for the logic in the IsNumericCustom, it really depends on what you're hoping to achieve / why int.TryParse / decimal.TryParse etc aren't appropriate. Here's a couple of implementations (using different function names).
using System.Text.RegularExpressions; //https://learn.microsoft.com/en-us/dotnet/api/system.text.regularexpressions.regex?view=netframework-4.7.2
//...
readonly Regex isNumeric = new Regex("^[+-]?\d*\.?\d*$", RegexOptions.Compiled); //treat "." as "0.0", ".9" as "0.9", etc
readonly Regex isInteger = new Regex("^[+-]?\d+$", RegexOptions.Compiled); //requires at least 1 digit; i.e. "" is not "0"
readonly Regex isIntegerLike = new Regex("^[+-]?\d*\.?\0*$", RegexOptions.Compiled); //same as integer, only 12.0 is treated as 12, whilst 12.1 is invalid; i.e. only an integer if we can remove digits after the decimal point without truncating the value.
//...
public bool IsNumeric(string input)
{
return isNumeric.IsMatch(input); //if you'd wanted 4.4 to be true, use this
}
public bool IsInteger(string input)
{
return isInteger.IsMatch(input); //as you want 4.4 to be false, use this
}
public bool IsIntegerLike(string input)
{
return isIntegerLike.IsMatch(input); //4.4 is false, but both 4 and 4.0 are true
}
From your requirements it appears that you want to use ASCII code in order to assert whether the string entered is numeric or not.
This is the code I have come up with:
string str;
var index = 1;
int strintoA = 0;
bool isNegative = false;
//ASCII list of numbers and signs
List<int> allowedValues = new List<int> { 43, 45, 48, 49, 50, 51, 52, 53, 54, 55, 56,
57 };
bool flag = false;
while (!flag)
{
Console.WriteLine("Enter a Number : ");
str = Console.ReadLine();
if (str.Count(item => allowedValues.Contains((int)item)) == str.Count())
{
foreach (var item in str.Reverse())
{
if (item != 43 && item != 45)
{
strintoA += index * (item - 48);
index = index * 10;
}
else if(item == 45)
{
isNegative = true;
}
}
if(isNegative)
{
strintoA *= -1;
}
Console.WriteLine("Entered String: " + str + " is a Number!");
flag = true;
}
else
{
Console.WriteLine("Please Enter Numbers Only.");
}
}
Console.ReadKey();
}
The allowedValues list contains the ASCII representation of numeric values and allowed signs(+ and -). The foreach loop will regenerates the int value inserted.
Hope it helps.
I'm remaking a text-based adventure game. During the character creation, I'd like for the user, at any time, to type 'skillset' and list all the traits that a specific race has. I've tried for a couple hours and can't seem to figure it out.
This is my character creation class.
public string userCommand_SeachSkill;
SkillSet searchSkill = new SkillSet();
public void Create_Character()
{
// CHOOSE GENDER //
do
{
validate = 0;
Console.Clear();
Console.Write("Are you male or female? (f/m): ");
Sex = Console.ReadLine().ToUpper();
if (Sex == "M" || Sex == "F")
{
validate = 1;
}
else if (Sex != "M" || Sex != "F")
{
Console.WriteLine("You must enter 'm' or 'f'");
}
} while (validate == 0);
And this is my Skill Set Class. Everything in the if/else statements are methods to print the traits of a race to the console. Let me know if there is anything else I can add to better ask my question. Thank you in advance! :)
ClassAttributes classes = new ClassAttributes();
Character character = new Character();
skillset = Console.ReadLine().ToUpper();
do
{
validate = 0;
if (skillset == "HUMAN")
{
classes.SkillSetHuman();
}
else if (skillset == "ORC")
{
classes.SkillSetOrc();
}
else if (skillset == "ELF")
{
classes.SkillSetElf();
}
else if (skillset == "EXIT")
{
validate = 1;
character.Create_Character();
}
} while (validate == 0);
I think you're looking for something like an event. C# Console Applications only seem to have one kind of event, it fires when ctrl+c or ctrl+break happens. You could handle your skillset input/output logic in the function handler
You can read more here:
https://msdn.microsoft.com/library/system.console.cancelkeypress(v=vs.110).aspx
If you really need the word to be typed, you could capture everything that is typed in a special function, instead of using regular Console.ReadLine(). Something like this:
public static string CustomReadLine()
{
ConsoleKeyInfo cki;
string capturedInput = "";
while (true)
{
cki = Console.ReadKey(true);
if (cki.Key == ConsoleKey.Enter)
break;
else if (cki.Key == ConsoleKey.Spacebar)
{
capturedInput += " ";
Console.Write(" ");
}
else if (cki.Key == ConsoleKey.Backspace)
{
capturedInput = capturedInput.Remove(capturedInput.Length - 1);
Console.Clear();
Console.Write(capturedInput);
}
else
{
capturedInput += cki.KeyChar;
Console.Write(cki.KeyChar);
}
if (capturedInput.ToUpper().Contains("SKILLSET"))
{
capturedInput = "";
skillsetTyped();
return "";
}
}
return capturedInput;
}
then inside your Create_Character, do
...
do
{
Console.Write("Are you male or female? (f/m): ");
Sex = CustomReadLine();
} while (String.IsNullOrEmpty(sex));
And finally, handle the skillset logic here
protected static void skillsetTyped()
{
Console.Write("\nWrite your skillset capture/display logic here\n");
}
This is just a draft and has some minor bugs, but I believe it's close to what you really want.
Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 5 years ago.
Improve this question
How do I get out of this loop?
I wrote a program that checks to see if corresponding places in the numbers are the same total. The console output should be true or false. I wrote that, and then added the top part that interacts with the user, and now I get stuck in a loop. How do I get out of it?
using System;
namespace DeliverablePart1
{
class DeliverablePart1
{
static void Main(string[] args)
{
string gameAnswer;
bool repeat1 = true, repeat2 = true;
while (repeat1 == true)
{
repeat2 = true;
Console.WriteLine("Would you like to compare 2 numbers to see if their corresponding place is same total?");
gameAnswer = Console.ReadLine();
while (repeat2 == true)
{
if (gameAnswer == "yes" || gameAnswer == "yes" || gameAnswer == "YES")
{
Console.WriteLine("Please enter a three digit whole number");
string firstValue = Console.ReadLine();
int firstNumber = ValidInteger(firstValue);
Console.WriteLine("Please enter a second three digit whole number");
string secondValue = Console.ReadLine();
int secondNumber = ValidInteger(secondValue);
repeat1 = false;
repeat2 = false;
}
else if (gameAnswer == "no" || gameAnswer == "No" || gameAnswer == "NO")
{
Console.WriteLine("Okay, exiting now");
repeat1 = false;
repeat2 = false;
}
else
{
Console.WriteLine("I do not understnad what you have said");
repeat2 = false;
}
void Add(int firstNumber, int secondNumber)
{
int length1 = firstNumber.ToString().Length;
int length2 = secondNumber.ToString().Length;
string userInput;
if (length1 == length2)
{
string Answer = Convert.ToString(Compare(firstNumber, secondNumber, length1));
}
else
{
userInput = "invalid user input - Check number of digits next time.";
Console.WriteLine(userInput);
Console.ReadKey();
}
Console.ReadKey();
}
int ValidInteger(string digit1)
{
int value = 0;
string notInt = "This is not an integer.";
{
bool successfullyParsed = int.TryParse(digit1, out value);
if (successfullyParsed)
{
int firstNumber = Convert.ToInt32(value);
return value;
}
else
{
Console.WriteLine(notInt);
Console.ReadKey();
Environment.Exit(0);
return value;
}
}
}
string Compare(int a, int b, int c)
{
int lastDigitA;
int lastDigitB;
lastDigitA = (a % 10);
lastDigitB = (b % 10);
int sumStatic = lastDigitA + lastDigitB;
do
{
lastDigitA = (a % 10);
lastDigitB = (b % 10);
a = a / 10;
b = b / 10;
c--;
int sumCompare = lastDigitA + lastDigitB;
if (sumCompare != sumStatic)
{
Console.WriteLine("False");
return "False";
}
}
while (c != 0);
Console.WriteLine("True");
return "True";
}
}
}
}
}
}
From my understanding, it looks like you want the user to enter in three ints (with some input validation), and put the three ints through the Compare() function. If the function returns true, then say "True" to the console, and if it's false then say "False" to the console. If that's the case, I refactored your code into this (and it doesn't get stuck in a loop):
using System;
namespace DeliverablePart1
{
internal class DeliverablePart1
{
private static void Main(string[] args)
{
Console.WriteLine("Would you like to compare 2 numbers to see if their corresponding place is same total?");
var shouldContinue = Console.ReadLine();
if (shouldContinue != null && shouldContinue.Equals("yes", StringComparison.CurrentCultureIgnoreCase))
{
var firstNum = GetIntFromUser("Please enter a three digit whole number");
var secondNum = GetIntFromUser("Please enter a three digit whole number");
var thirdNum = GetIntFromUser("Please enter a three digit whole number");
Console.WriteLine(Compare(firstNum, secondNum, thirdNum) ? "True" : "False");
}
else
{
Console.WriteLine("Exiting");
}
// waits for the user to press a key to exit the app, so that they can see their result
Console.ReadKey();
}
/// <summary>
/// Makes the user enter in a three digit number, and exits if they say "no"
/// </summary>
/// <param name="msg">The message prompt to ask for the integer</param>
/// <returns>System.Int32., or will exit</returns>
public static int GetIntFromUser(string msg)
{
while (true)
{
Console.WriteLine(msg);
var valFromUser = Console.ReadLine()?.Trim();
if (valFromUser != null)
{
int result;
if (int.TryParse(valFromUser.Trim(), out result) && valFromUser.Length == 3)
{
return result;
}
if (valFromUser.Equals("no", StringComparison.CurrentCultureIgnoreCase))
{
Console.WriteLine("Exiting.");
Environment.Exit(0);
}
}
Console.WriteLine("Hmm, that's not a three digit number. Try again.");
}
}
public static bool Compare(int a, int b, int c)
{
var lastDigitA = a % 10;
var lastDigitB = b % 10;
var sumStatic = lastDigitA + lastDigitB;
do
{
lastDigitA = a % 10;
lastDigitB = b % 10;
a = a / 10;
b = b / 10;
c--;
var sumCompare = lastDigitA + lastDigitB;
if (sumCompare != sumStatic)
{
return false;
}
} while (c != 0);
return true;
}
}
}
This is contain from method, which writes hidden letters. When I hit a backspace, I need somehow to delete char * from console.
private static string Password()
{
bool enter=true;
string pass="";
do
{
char letter = Console.ReadKey(true).KeyChar;
if (letter == (char)13)
{ enter = false; }
else if (letter == (char)8 && pass.Length >= 1)
{
pass = pass.Remove(pass.Length - 1);
Console.Write("\b");
}
else
{
pass += letter;
Console.Write("*");
}
} while (enter);
Console.WriteLine();
return pass;
}
I searched for an answer but the command Console.Write("\b"); but it doesn't seem to work correctly.
You can set the cursor's position back one, write a null character, then move it back again. Like this:
private static string Password()
{
bool enter = true;
string pass = "";
do
{
char letter = Console.ReadKey(true).KeyChar;
if (letter == (char)13)
{ enter = false; }
else if (letter == (char)8 && pass.Length >= 1)
{
pass = pass.Remove(pass.Length - 1);
Console.CursorLeft--;
Console.Write('\0');
Console.CursorLeft--;
}
//Additionally, don't print backspaces if it's the first character.
else if (letter != (char)8)
{
pass += letter;
Console.Write("*");
}
} while (enter);
Console.WriteLine();
return pass;
}
Try this:
Console.Write("\b \b");
I tried the following code...
string pass = "";
Console.Write("Enter your password: ");
ConsoleKeyInfo key;
do
{
key = Console.ReadKey(true);
// Backspace Should Not Work
if (key.Key != ConsoleKey.Backspace)
{
pass += key.KeyChar;
Console.Write("*");
}
else
{
Console.Write("\b");
}
}
// Stops Receving Keys Once Enter is Pressed
while (key.Key != ConsoleKey.Enter);
Console.WriteLine();
Console.WriteLine("The Password You entered is : " + pass);
But this way the backspace functionality doesn't work while typing the password.
Any suggestion?
Console.Write("\b \b"); will delete the asterisk character from the screen, but you do not have any code within your else block that removes the previously entered character from your pass string variable.
Here's the relevant working code that should do what you require:
var pass = string.Empty;
ConsoleKey key;
do
{
var keyInfo = Console.ReadKey(intercept: true);
key = keyInfo.Key;
if (key == ConsoleKey.Backspace && pass.Length > 0)
{
Console.Write("\b \b");
pass = pass[0..^1];
}
else if (!char.IsControl(keyInfo.KeyChar))
{
Console.Write("*");
pass += keyInfo.KeyChar;
}
} while (key != ConsoleKey.Enter);
For this you should use the System.Security.SecureString
public SecureString GetPassword()
{
var pwd = new SecureString();
while (true)
{
ConsoleKeyInfo i = Console.ReadKey(true);
if (i.Key == ConsoleKey.Enter)
{
break;
}
else if (i.Key == ConsoleKey.Backspace)
{
if (pwd.Length > 0)
{
pwd.RemoveAt(pwd.Length - 1);
Console.Write("\b \b");
}
}
else if (i.KeyChar != '\u0000' ) // KeyChar == '\u0000' if the key pressed does not correspond to a printable character, e.g. F1, Pause-Break, etc
{
pwd.AppendChar(i.KeyChar);
Console.Write("*");
}
}
return pwd;
}
Complete solution, vanilla C# .net 3.5+
Cut & Paste
:)
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleReadPasswords
{
class Program
{
static void Main(string[] args)
{
Console.Write("Password:");
string password = Orb.App.Console.ReadPassword();
Console.WriteLine("Sorry - I just can't keep a secret!");
Console.WriteLine("Your password was:\n<Password>{0}</Password>", password);
Console.ReadLine();
}
}
}
namespace Orb.App
{
/// <summary>
/// Adds some nice help to the console. Static extension methods don't exist (probably for a good reason) so the next best thing is congruent naming.
/// </summary>
static public class Console
{
/// <summary>
/// Like System.Console.ReadLine(), only with a mask.
/// </summary>
/// <param name="mask">a <c>char</c> representing your choice of console mask</param>
/// <returns>the string the user typed in </returns>
public static string ReadPassword(char mask)
{
const int ENTER = 13, BACKSP = 8, CTRLBACKSP = 127;
int[] FILTERED = { 0, 27, 9, 10 /*, 32 space, if you care */ }; // const
var pass = new Stack<char>();
char chr = (char)0;
while ((chr = System.Console.ReadKey(true).KeyChar) != ENTER)
{
if (chr == BACKSP)
{
if (pass.Count > 0)
{
System.Console.Write("\b \b");
pass.Pop();
}
}
else if (chr == CTRLBACKSP)
{
while (pass.Count > 0)
{
System.Console.Write("\b \b");
pass.Pop();
}
}
else if (FILTERED.Count(x => chr == x) > 0) { }
else
{
pass.Push((char)chr);
System.Console.Write(mask);
}
}
System.Console.WriteLine();
return new string(pass.Reverse().ToArray());
}
/// <summary>
/// Like System.Console.ReadLine(), only with a mask.
/// </summary>
/// <returns>the string the user typed in </returns>
public static string ReadPassword()
{
return Orb.App.Console.ReadPassword('*');
}
}
}
Taking the top answer, as well as the suggestions from its comments, and modifying it to use SecureString instead of String, test for all control keys, and not error or write an extra "*" to the screen when the password length is 0, my solution is:
public static SecureString getPasswordFromConsole(String displayMessage) {
SecureString pass = new SecureString();
Console.Write(displayMessage);
ConsoleKeyInfo key;
do {
key = Console.ReadKey(true);
// Backspace Should Not Work
if (!char.IsControl(key.KeyChar)) {
pass.AppendChar(key.KeyChar);
Console.Write("*");
} else {
if (key.Key == ConsoleKey.Backspace && pass.Length > 0) {
pass.RemoveAt(pass.Length - 1);
Console.Write("\b \b");
}
}
}
// Stops Receving Keys Once Enter is Pressed
while (key.Key != ConsoleKey.Enter);
return pass;
}
Mine ignores control characters and handles line wrapping:
public static string ReadLineMasked(char mask = '*')
{
var sb = new StringBuilder();
ConsoleKeyInfo keyInfo;
while ((keyInfo = Console.ReadKey(true)).Key != ConsoleKey.Enter)
{
if (!char.IsControl(keyInfo.KeyChar))
{
sb.Append(keyInfo.KeyChar);
Console.Write(mask);
}
else if (keyInfo.Key == ConsoleKey.Backspace && sb.Length > 0)
{
sb.Remove(sb.Length - 1, 1);
if (Console.CursorLeft == 0)
{
Console.SetCursorPosition(Console.BufferWidth - 1, Console.CursorTop - 1);
Console.Write(' ');
Console.SetCursorPosition(Console.BufferWidth - 1, Console.CursorTop - 1);
}
else Console.Write("\b \b");
}
}
Console.WriteLine();
return sb.ToString();
}
This masks the password with a red square, then reverts back to the original colours once the password has been entered.
It doesn't stop the user from using copy/paste to get the password, but if it's more just about stopping someone looking over your shoulder, this is a good quick solution.
Console.Write("Password ");
ConsoleColor origBG = Console.BackgroundColor; // Store original values
ConsoleColor origFG = Console.ForegroundColor;
Console.BackgroundColor = ConsoleColor.Red; // Set the block colour (could be anything)
Console.ForegroundColor = ConsoleColor.Red;
string Password = Console.ReadLine(); // read the password
Console.BackgroundColor= origBG; // revert back to original
Console.ForegroundColor= origFG;
Reading console input is hard, you need to handle special keys like Ctrl, Alt, also cursor keys and Backspace/Delete. On some keyboard layouts, like Swedish Ctrl is even needed to enter keys that exist directly on US keyboard. I believe that trying to handle this using the "low-level" Console.ReadKey(true) is just very hard, so the easiest and most robust way is to just to disable "console input echo" during entering password using a bit of WINAPI.
The sample below is based on answer to Read a password from std::cin question.
private enum StdHandle
{
Input = -10,
Output = -11,
Error = -12,
}
private enum ConsoleMode
{
ENABLE_ECHO_INPUT = 4
}
[DllImport("kernel32.dll", SetLastError = true)]
private static extern IntPtr GetStdHandle(StdHandle nStdHandle);
[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool GetConsoleMode(IntPtr hConsoleHandle, out int lpMode);
[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool SetConsoleMode(IntPtr hConsoleHandle, int dwMode);
public static string ReadPassword()
{
IntPtr stdInputHandle = GetStdHandle(StdHandle.Input);
if (stdInputHandle == IntPtr.Zero)
{
throw new InvalidOperationException("No console input");
}
int previousConsoleMode;
if (!GetConsoleMode(stdInputHandle , out previousConsoleMode))
{
throw new Win32Exception(Marshal.GetLastWin32Error(), "Could not get console mode.");
}
// disable console input echo
if (!SetConsoleMode(stdInputHandle , previousConsoleMode & ~(int)ConsoleMode.ENABLE_ECHO_INPUT))
{
throw new Win32Exception(Marshal.GetLastWin32Error(), "Could not disable console input echo.");
}
// just read the password using standard Console.ReadLine()
string password = Console.ReadLine();
// reset console mode to previous
if (!SetConsoleMode(stdInputHandle , previousConsoleMode))
{
throw new Win32Exception(Marshal.GetLastWin32Error(), "Could not reset console mode.");
}
return password;
}
I found a bug in shermy's vanilla C# 3.5 .NET solution which otherwise works a charm. I have also incorporated Damian Leszczyński - Vash's SecureString idea here but you can use an ordinary string if you prefer.
THE BUG: If you press backspace during the password prompt and the current length of the password is 0 then an asterisk is incorrectly inserted in the password mask. To fix this bug modify the following method.
public static string ReadPassword(char mask)
{
const int ENTER = 13, BACKSP = 8, CTRLBACKSP = 127;
int[] FILTERED = { 0, 27, 9, 10 /*, 32 space, if you care */ }; // const
SecureString securePass = new SecureString();
char chr = (char)0;
while ((chr = System.Console.ReadKey(true).KeyChar) != ENTER)
{
if (((chr == BACKSP) || (chr == CTRLBACKSP))
&& (securePass.Length > 0))
{
System.Console.Write("\b \b");
securePass.RemoveAt(securePass.Length - 1);
}
// Don't append * when length is 0 and backspace is selected
else if (((chr == BACKSP) || (chr == CTRLBACKSP)) && (securePass.Length == 0))
{
}
// Don't append when a filtered char is detected
else if (FILTERED.Count(x => chr == x) > 0)
{
}
// Append and write * mask
else
{
securePass.AppendChar(chr);
System.Console.Write(mask);
}
}
System.Console.WriteLine();
IntPtr ptr = new IntPtr();
ptr = Marshal.SecureStringToBSTR(securePass);
string plainPass = Marshal.PtrToStringBSTR(ptr);
Marshal.ZeroFreeBSTR(ptr);
return plainPass;
}
(My) nuget package to do this, based on the top answer:
install-package PanoramicData.ConsoleExtensions
Usage:
using PanoramicData.ConsoleExtensions;
...
Console.Write("Password: ");
var password = ConsolePlus.ReadPassword();
Console.WriteLine();
Project URL: https://github.com/panoramicdata/PanoramicData.ConsoleExtensions
Pull requests welcome.
Here's a version that adds support for the Escape key (which returns a null string)
public static string ReadPassword()
{
string password = "";
while (true)
{
ConsoleKeyInfo key = Console.ReadKey(true);
switch (key.Key)
{
case ConsoleKey.Escape:
return null;
case ConsoleKey.Enter:
return password;
case ConsoleKey.Backspace:
if (password.Length > 0)
{
password = password.Substring(0, (password.Length - 1));
Console.Write("\b \b");
}
break;
default:
password += key.KeyChar;
Console.Write("*");
break;
}
}
}
Jeez guys
static string ReadPasswordLine()
{
string pass = "";
ConsoleKeyInfo key;
do
{
key = Console.ReadKey(true);
if (key.Key != ConsoleKey.Enter)
{
if (!(key.KeyChar < ' '))
{
pass += key.KeyChar;
Console.Write("*");
}
else if (key.Key == ConsoleKey.Backspace && pass.Length > 0)
{
Console.Write(Convert.ToChar(ConsoleKey.Backspace));
pass = pass.Remove(pass.Length - 1);
Console.Write(" ");
Console.Write(Convert.ToChar(ConsoleKey.Backspace));
}
}
} while (key.Key != ConsoleKey.Enter);
return pass;
}
You could append your keys to an accumulating linked list.
When a backspace key is received, remove the last key from the list.
When you receive the enter key, collapse your list into a string and do the rest of your work.
I made some changes for backspace
string pass = "";
Console.Write("Enter your password: ");
ConsoleKeyInfo key;
do
{
key = Console.ReadKey(true);
// Backspace Should Not Work
if (key.Key != ConsoleKey.Backspace)
{
pass += key.KeyChar;
Console.Write("*");
}
else
{
pass = pass.Remove(pass.Length - 1);
Console.Write("\b \b");
}
}
// Stops Receving Keys Once Enter is Pressed
while (key.Key != ConsoleKey.Enter);
Console.WriteLine();
Console.WriteLine("The Password You entered is : " + pass);
I have updated Ronnie's version after spending way too much time trying to enter a password only to find out that I had my CAPS LOCK on!
With this version what ever the message is in _CapsLockMessage will "float" at the end of the typing area and will be displayed in red.
This version takes a bit more code and does require a polling loop. On my computer CPU usage about 3% to 4%, but one could always add a small Sleep() value to decrease CPU usage if needed.
private const string _CapsLockMessage = " CAPS LOCK";
/// <summary>
/// Like System.Console.ReadLine(), only with a mask.
/// </summary>
/// <param name="mask">a <c>char</c> representing your choice of console mask</param>
/// <returns>the string the user typed in</returns>
public static string ReadLineMasked(char mask = '*')
{
// Taken from http://stackoverflow.com/a/19770778/486660
var consoleLine = new StringBuilder();
ConsoleKeyInfo keyInfo;
bool isDone;
bool isAlreadyLocked;
bool isCapsLockOn;
int cursorLeft;
int cursorTop;
ConsoleColor originalForegroundColor;
isDone = false;
isAlreadyLocked = Console.CapsLock;
while (isDone == false)
{
isCapsLockOn = Console.CapsLock;
if (isCapsLockOn != isAlreadyLocked)
{
if (isCapsLockOn)
{
cursorLeft = Console.CursorLeft;
cursorTop = Console.CursorTop;
originalForegroundColor = Console.ForegroundColor;
Console.ForegroundColor = ConsoleColor.Red;
Console.Write("{0}", _CapsLockMessage);
Console.SetCursorPosition(cursorLeft, cursorTop);
Console.ForegroundColor = originalForegroundColor;
}
else
{
cursorLeft = Console.CursorLeft;
cursorTop = Console.CursorTop;
Console.Write("{0}", string.Empty.PadRight(_CapsLockMessage.Length));
Console.SetCursorPosition(cursorLeft, cursorTop);
}
isAlreadyLocked = isCapsLockOn;
}
if (Console.KeyAvailable)
{
keyInfo = Console.ReadKey(intercept: true);
if (keyInfo.Key == ConsoleKey.Enter)
{
isDone = true;
continue;
}
if (!char.IsControl(keyInfo.KeyChar))
{
consoleLine.Append(keyInfo.KeyChar);
Console.Write(mask);
}
else if (keyInfo.Key == ConsoleKey.Backspace && consoleLine.Length > 0)
{
consoleLine.Remove(consoleLine.Length - 1, 1);
if (Console.CursorLeft == 0)
{
Console.SetCursorPosition(Console.BufferWidth - 1, Console.CursorTop - 1);
Console.Write(' ');
Console.SetCursorPosition(Console.BufferWidth - 1, Console.CursorTop - 1);
}
else
{
Console.Write("\b \b");
}
}
if (isCapsLockOn)
{
cursorLeft = Console.CursorLeft;
cursorTop = Console.CursorTop;
originalForegroundColor = Console.ForegroundColor;
Console.ForegroundColor = ConsoleColor.Red;
Console.Write("{0}", _CapsLockMessage);
Console.CursorLeft = cursorLeft;
Console.CursorTop = cursorTop;
Console.ForegroundColor = originalForegroundColor;
}
}
}
Console.WriteLine();
return consoleLine.ToString();
}
Here is my simple version.
Every time you hit a key, delete all from console and draw as many '*' as the length of password string is.
int chr = 0;
string pass = "";
const int ENTER = 13;
const int BS = 8;
do
{
chr = Console.ReadKey().KeyChar;
Console.Clear(); //imediately clear the char you printed
//if the char is not 'return' or 'backspace' add it to pass string
if (chr != ENTER && chr != BS) pass += (char)chr;
//if you hit backspace remove last char from pass string
if (chr == BS) pass = pass.Remove(pass.Length-1, 1);
for (int i = 0; i < pass.Length; i++)
{
Console.Write('*');
}
}
while (chr != ENTER);
Console.Write("\n");
Console.Write(pass);
Console.Read(); //just to see the pass
If I understand this correctly, you're trying to make backspace delete both the visible * character on screen and the cached character in your pass variable?
If so, then just change your else block to this:
else
{
Console.Write("\b");
pass = pass.Remove(pass.Length -1);
}
I just improve code from ask I simple and just work
string pass = ""; //create empty password string
Console.Write("Enter your password: ");
ConsoleKeyInfo key;
int passLen = 0; // base password length
do
{
key = Console.ReadKey(true); //reading keyboard key
if (key.Key == ConsoleKey.Escape) Environment.Exit(0); // If key is escape console will close (optional)
if (key.Key != ConsoleKey.Backspace && key.Key != ConsoleKey.Enter) // on key with is not bacspase and enter
{
pass += key.KeyChar; //password string add key value
Console.Write("*"); // and print star as masked char
passLen++; // upgrading password length
}
else if (passLen > 0 && key.Key == ConsoleKey.Backspace) //if password have a any symbol and u press Backspace
{
Console.Write("\b \b"); //Backspace delete star symbol and coursor back in line
passLen--; // password length is one less
pass = pass[0..^1]; // new string passowrd is string without last charter
}
}
while (key.Key != ConsoleKey.Enter); // if you press enter this stop execute with your password
Console.WriteLine();
Console.WriteLine("The Password You entered is : " + pass);
string pass = "";
Console.WriteLine("Enter your password: ");
ConsoleKeyInfo key;
do {
key = Console.ReadKey(true);
if (key.Key != ConsoleKey.Backspace) {
pass += key.KeyChar;
Console.Write("*");
} else {
Console.Write("\b \b");
char[] pas = pass.ToCharArray();
string temp = "";
for (int i = 0; i < pass.Length - 1; i++) {
temp += pas[i];
}
pass = temp;
}
}
// Stops Receving Keys Once Enter is Pressed
while (key.Key != ConsoleKey.Enter);
Console.WriteLine();
Console.WriteLine("The Password You entered is : " + pass);