I have been trying to do error handling so that if someone just hit enter and didnt input a value it would ask for a proper value. It appears that just pressing enter returns a value via readline although i cant determine what value here is my code which is supposed to handle null values

        public static string StringTester(string? input)
        {
            string output;
            if (input != null)
            {
                Console.WriteLine("Not null nani");
            }
            if (input == null)
            {
                Console.WriteLine("Please input valid value");
                output = StringTester(Console.ReadLine());

            } else if (input.Contains('\n') ^ input.Contains(' ') ^ input.Contains('\r'))
            {
                Console.WriteLine("Please input valid value");
                output = StringTester(Console.ReadLine());
            }
            else
            {
                output = input;
            }
            return output;
        }

I tried to find the return value on google and through the documentation by microsoft on readline however none came up. I thought maybe it is reading a new line so i added a new line into the error handling.

CodePudding user response：

Console.ReadLine will return a string containing the characters that the user typed before hitting Enter. If they didn't type any characters then that string will be empty, i.e. Console.ReadLine will return string.Empty.

CodePudding user response：

You can try using String.IsNullOrEmpty(String) for situations like this.

It will check if the string is null, or empty ("")

CodePudding user response：

Console.ReadLine will return an empty string, if the user doesn't enters anything. To check for null, you can use the string.IsNullOrEmpty`

CodePudding user response：

For check an empty value from input you have to use:

if(string.IsNullOrEmpty(*yourString*)){//error handling}