C#•2mo ago

Null Literal and NUll reference problems

Hey guys, Beginer at using Files here. Im running into 2 errors while trying to read the contents of a text file, then putting the contents into a consructor. "CS8600 Converting null literal or possible null value to non-nullable type.35
Warning (active) CS8603 Possible null reference return. 65" i dont really understand what im missing tho.

        public static Employees[] EmployeeRead(string Filename)
        {
            try
            {
                FileInfo FileProperty = new FileInfo(Filename);
                Console.WriteLine($"File name: {FileProperty.Name}");

                FileStream file = new FileStream(Filename, FileMode.Open, FileAccess.Read);
                StreamReader text = new StreamReader(file);

                try
                {
                    Employees[] employees = new Employees[13];

                    string line;
                    int LineCount = 0;


                    while ((line = text.ReadLine()) != null) {

                        employees[LineCount] = new Employees(line, Convert.ToInt32(line[1]), Convert.ToDecimal(line[2]), Convert.ToDouble(line[3]));
                        LineCount++;
                    }


                    foreach (Employees employee in employees) {
                        employee.ToString();
                    }
                    text.Close();
                    return employees;


                } catch (InvalidCastException)
                {
                    Console.WriteLine("Some bad conversion");
                   
                   
                }catch (IOException)
                {
                    Console.WriteLine("idk");
                    
                }

            }catch (IOException)
            {
                Console.WriteLine("Smth wrong with the file path or reading file");
                
            }
            return null;
        }

        public static Employees[] EmployeeRead(string Filename)
        {
            try
            {
                FileInfo FileProperty = new FileInfo(Filename);
                Console.WriteLine($"File name: {FileProperty.Name}");

                FileStream file = new FileStream(Filename, FileMode.Open, FileAccess.Read);
                StreamReader text = new StreamReader(file);

                try
                {
                    Employees[] employees = new Employees[13];

                    string line;
                    int LineCount = 0;


                    while ((line = text.ReadLine()) != null) {

                        employees[LineCount] = new Employees(line, Convert.ToInt32(line[1]), Convert.ToDecimal(line[2]), Convert.ToDouble(line[3]));
                        LineCount++;
                    }


                    foreach (Employees employee in employees) {
                        employee.ToString();
                    }
                    text.Close();
                    return employees;


                } catch (InvalidCastException)
                {
                    Console.WriteLine("Some bad conversion");
                   
                   
                }catch (IOException)
                {
                    Console.WriteLine("idk");
                    
                }

            }catch (IOException)
            {
                Console.WriteLine("Smth wrong with the file path or reading file");
                
            }
            return null;
        }

10 Replies

reflectronic•2mo ago

well, firstly, those are not errors it tells you it is a warning, not an error

jcotton42•2mo ago

please indicate which line is giving the warning don't make us count line numbers

reflectronic•2mo ago

i mean, the error is certainly the line return null;, because the function returns Employees[] an Employees[] "should not" be null, which is why you are getting the warning it would like you to return Employees[]? instead, which indicates that it may be null

TimVibes•2mo ago

It's withing the whole loop condition.

jcotton42•2mo ago

I mean yeah. But I'm marginally petty and want to teach good asking behavior.

TimVibes•2mo ago

I meant for it to return null if the employee file wasn't read of object not initialised Is there a way to format code better on this GC? The java GC does formating pretty well

reflectronic•2mo ago

the loop condition is the same deal, you are saying line is never null, but you assign ReadLine() to it, which could be null. it wants you to write string? line instead, to show that line could be null

TimVibes•2mo ago

Guys can you take a look at the while loop. Trouble begun over there, even while disregarding the final return null statement I also tried the string? Line but it was still bringing me problems I'll get home and try again tho

Bailey•2mo ago

Hi, I'm looking at the code and there can be a number of causes. Hope you can use the following: I would replace the array with a list like: List<Employees> listEmployees = new List<Employees>(); and add items using: listEmployees.Add(new Employees(line, Convert.ToInt32(line[1]), Convert.ToDecimal(line[2]), Convert.ToDouble(line[3]))); the second part is about ul reference. What you do in the code: employees[LineCount] = new Employees(line, Convert.ToInt32(line[1]), Convert.ToDecimal(line[2]), Convert.ToDouble(line[3])); - convert the second char into integer - convert the third character into decimal - convert the fourth char into double. When the line does not have the chars, the array (a string is under the hood an array of chars) it will give a null reference error. There are more possible tests you can add but first start something like below within the loop. if (string.IsNullOrEmpty(line) || line.Length <5 ) { // give some error or message and put breakpoint to look at data }

TimVibes•2mo ago

Sorry for the late response. Using an array was a strict requirement for the project

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Null Literal and NUll reference problems