C#•2y ago

❔ Dereference of a possibly null reference.

            do {
                try {
                    choice = char.Parse(Console.ReadLine().ToUpper()); // <<< this line throws the warning

                    switch (choice) {
                        case 'P':
                            Console.WriteLine("Ok");
                            break;
                        case 'Q':
                            Environment.Exit(0);
                            break;
                        default:
                            Console.Write("Try again: ");
                            break;
                    }
                }
                catch (Exception) {
                    Console.Write("Try again: ");
                }
            }
            while (choice != 'P' || choice != 'Q');

            do {
                try {
                    choice = char.Parse(Console.ReadLine().ToUpper()); // <<< this line throws the warning

                    switch (choice) {
                        case 'P':
                            Console.WriteLine("Ok");
                            break;
                        case 'Q':
                            Environment.Exit(0);
                            break;
                        default:
                            Console.Write("Try again: ");
                            break;
                    }
                }
                catch (Exception) {
                    Console.Write("Try again: ");
                }
            }
            while (choice != 'P' || choice != 'Q');

11 Replies

bialasik__•2y ago

i tried setting the char choice = ' ', but i still get it and cannot find solutions online

Servator•2y ago

Console.ReadLine() returns string?

Servator•2y ago

But you are trying to parse with char

bialasik__•2y ago

yh i do this in vs2022 and i get no warning, but when i had to switch to vscode it throws this i normally do char.Parse and never get that warning in vs2022

Servator•2y ago

oh you are talking about warning ReadLine() returns string? ? indicates its nullable You need to handle null situation or just tell the compiler dont worry about that with null forgive operator

char.Parse(Console.ReadLine()!.ToUpper());

char.Parse(Console.ReadLine()!.ToUpper());

! tells the compiler "I'm sure it's not null don't worry about it"

bialasik__•2y ago

ahhh never knew about that operator thank you

333fred•2y ago

I would generally advise you try not use the ! operator unless you have no other choice In this instance, you should check for null

Servator•2y ago

yeah exactly

bialasik__•2y ago

alr

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Dereference of a possibly null reference.