Int.Parse, Input String Was Not in a Correct Format

int.Parse, Input string was not in a correct format

If you're looking to default to 0 on an empty textbox (and throw an exception on poorly formatted input):

int i = string.IsNullOrEmpty(Textbox1.Text) ? 0 : int.Parse(Textbox1.Text);

If you're looking to default to 0 with any poorly formatted input:

int i;
if (!int.TryParse(Textbox1.Text, out i)) i = 0;

System.FormatException: Input string was not in a correct format from an int.Parse

int.Parse() will fail with that exception if the value you provide it is not capable of being converted to an int, and as written you have no checks on the string being read from the console to verify that is the case before passing it to the method.

You can use int.TryParse() instead, which gives you a bit more control over how to handle a failure by returning a boolean indicating success. You might present an error message instead, and ask the user to resubmit.

string input = Console.ReadLine();
int result;

if(int.TryParse(input, out result)) // TryParse returns a boolean showing whether the parse worked
{
   // then perform your behavior safely
}

int.Parse is not working with string value (System.FormatException: Input string was not in a correct format )

Because of int femaleWeight = int.Parse(Console.ReadLine());

int.Parse method will throw FormatException if input can not be converted to integer.

How do I handle input string was not in correct format

A System.FormatException happens when you want to "parse" a string to another type, like an integer, that makes a number in text be represented as a real number, in your case, you are calling Convert.ToInt32, be sure that whatever string being passed as argument to this method, don't overflow the capabilities of the Int32 struct, or that the text does not contain letters or decimal points. If that is the case, to verify if a number is valid use int.TryParse, it will only return true if the text is in a correct format like so:

if (int.TryParse("5", out int number))
{
    // Do something with that number
}

Here, if "5" is not a number, the if block will be completely skipped.

Input string was not in a correct format Int32.Parse

Double-check that spell.spellName.Length is 1 and (int)spell.spellName[0] is 0x30. The debugger display might not show all the characters that are actually in the string.

If the string is from user input it might be a good idea to be prepared for such incorrectly formed input by either catching the exception or using int.TryParse.

FormatException int.Parse() even when passing correct format string value

You have an invisible character at the end (after the 8).

You'll notice that the following evaluates to true:

AllowedFileSize[7] == '\u202c'

One approach could be

return int.Parse(AllowedFileSize.Trim('\u202c'));

But that's just a "quick" fix, and you'll likely just want to fix the json. Delete the whole value, including the double quotes and re-type those as well.

Your editor probably won't capture that hidden character if you do something like double click the value to edit (Visual Studio didn't when I tested this).

Input string was not in a correct format

The error means that the string you're trying to parse an integer from doesn't actually contain a valid integer.

It's extremely unlikely that the text boxes will contain a valid integer immediately when the form is created - which is where you're getting the integer values. It would make much more sense to update a and b in the button click events (in the same way that you are in the constructor). Also, check out the Int.TryParse method - it's much easier to use if the string might not actually contain an integer - it doesn't throw an exception so it's easier to recover from.

Input String Was Not In A Correct Format. int.Parse(array[0]);

You are not giving valid integer value to int.Parse because of that you receive this exception. In this case you can't use int.TryParse because you need your game ID. What I advice you is to debug your code and see what are the value of array.

You need to add this lines if you want to see it in the console.

foreach(string sArr in array)
{
    Console.WriteLine(sArr);
}

After that see on which position is your game ID and put it in the int.Parse.

Int.Parse, Input String Was Not in a Correct Format