C#•6mo ago

✅ Console Readline accepting empty value.

Hi all, I'm trying to set console readline to not accept empty value (""). However, I've tried a bunch of different options and I still get "System.FormatException: 'The input string '' was not in a correct format.' " Here is my code

do
{
    Console.WriteLine("Player 1, how far away from the city do you want to station the Manticore? ");
    manticoreDistance = Convert.ToInt32(readResult);
} while (manticoreDistance < 0 || manticoreDistance > 100);
Console.Clear();

do
{
    Console.WriteLine("Player 1, how far away from the city do you want to station the Manticore? ");
    manticoreDistance = Convert.ToInt32(readResult);
} while (manticoreDistance < 0 || manticoreDistance > 100);
Console.Clear();

Ideally the goal was to make a loop that displays a message stating that a number needs to be entered.

8 Replies

SY•6mo ago

Im not sure if understood correctly i think u mean if (manticoreDistance == string.Empty) { // handle it }

d3adin.•6mo ago

I will give this a try to see if it works. I wasn't sure how to explain it

cap5lut•6mo ago

a much simpler option would be to simply use $tryparse btw

MODiX•6mo ago

When you don't know if a string is actually a number when handling user input, use int.TryParse (or variants, e.g. double.TryParse)

if(int.TryParse("123", out int number))
{
    var total = number + 1;
    Console.WriteLine(total); // output: 124
}

if(int.TryParse("123", out int number))
{
    var total = number + 1;
    Console.WriteLine(total); // output: 124
}

TryParse returns a bool, where true indicates successful parsing. Remarks: - Avoid int.Parse if you do not know if the value parsed is definitely a number. - Avoid Convert.ToInt32 entirely, this is an older method and Parse should be preferred where you know the string can be parsed. Read more here

cap5lut•6mo ago

would be something like

Console.WriteLine("Player 1, how far away from the city do you want to station the Manticore?");
int manticoreDistance;
while (!int.TryParse(Console.ReadLine(), out manticoreDistance) || manticoreDistance < 0 || manticoreDistance > 100)
{
    Console.WriteLine("Input was incorrect. Please enter a distance between 0 and 100.");
}
// manticoreDistance is >= 0 and <= 100

Console.WriteLine("Player 1, how far away from the city do you want to station the Manticore?");
int manticoreDistance;
while (!int.TryParse(Console.ReadLine(), out manticoreDistance) || manticoreDistance < 0 || manticoreDistance > 100)
{
    Console.WriteLine("Input was incorrect. Please enter a distance between 0 and 100.");
}
// manticoreDistance is >= 0 and <= 100

d3adin.•6mo ago

Thank you so much! This works exactly how I wanted it to work! I didn't know you can add Console.ReadLine to the loop condition 😮

cap5lut•6mo ago

glad i could help o7 if ur question is answered dont forget to $close the channel

MODiX•6mo ago

Use the /close command to mark a forum thread as answered

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✅ Console Readline accepting empty value.