CODEWITHSUNDEEP
c#stringbooleantryparse
Ilan Ezersky
Ilan Ezersky

Reputation: 15

Numeric string validation in c#

I'm trying to validate if the 'columnsValidation' is a numeric string, and convert it to an int, if so.

For some reason, I end up in an endless loop, because 'isNumber' always equals false...

This code is part of my lottery project.

I hope that my question is clear enough, if additional information is needed just tell me and I'll answer.

Thanks in advance, Ilan. 

Console.WriteLine("Please insert the number of rows: ");

        string columnsValidation = Console.ReadLine();

        bool isNumber = false;

            while(isNumber == false)
            {
                bool.TryParse(columnsValidation, out isNumber);
                if (isNumber == true)
                    columns = int.Parse(columnsValidation);
                else
                {
                    Console.WriteLine("You've inserted an invalid value, please try again.");
                    columnsValidation = Console.ReadLine();
                }
            }

Upvotes: 0

Views: 211

Answers (3)

Muhammad Umar
Muhammad Umar

Reputation: 3781

Why not you use Int.TryParse

int columns = 0;

while(true)
{
    if (!Int32.TryParse(columnsValidation,out columns)
    {
        Console.WriteLine("You've inserted an invalid value, please try again.");
        columnsValidation = Console.ReadLine();
    }
    else
    {
        break;
    }
}

Upvotes: 0

Selman Genç
Selman Genç

Reputation: 101681

You need to use int.TryParse with columnsValidation

if (!int.TryParse(columnsValidation,out columns)
{
     Console.WriteLine("You've inserted an invalid value, please try again.");
     columnsValidation = Console.ReadLine();
}
else
{ 
    isNumber = true;
}

Upvotes: 2

Andrei
Andrei

Reputation: 56688

Correct your usage of TryParse:

isNumber = int.TryParse(columnsValidation, out columns);

TryParse returns boolean indicating whether the parsing succeeded, and in case of success sets out param with the parsing result.

Upvotes: 2

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