Question

the problem I’m having is to validate the input means putting it in a try catch which then wont pass the variable through and I’m getting this error:

Use of unassigned local variable ‘MainMenuSelection’

I’ve validated using this method before but for some reason it’s not working now, please help

//Take the menu selection
try
{
    mainMenuSelection = byte.Parse(Console.ReadLine());
}
catch
{
    Console.WriteLine("Please enter a valid selection");
}


switch (mainMenuSelection) //Where error is shown

Answer 1

Obviously user can input anything which would not be parsed as a single byte. Try out using Byte.TryParse() method which does not generate exception and just return status flag.

You can go further and add more analysis for an user input if needed:

// Initialize by a default value to avoid
// "Use of unassigned local variable 'MainMenuSelection'" error
byte mainMenuSelection = 0x00;    
string input = Console.ReadLine();

// If acceptable - remove possible spaces at the start and the end of a string
input = input.Trim();
if (input.Lenght > 1)
{
   // can you do anything if user entered multiple characters?
}
else
{
   if (!byte.TryParse(input, out mainMenuSelection))
   {
       // parsing error
   }
   else
   {
       // ok, do switch
   }
}

Also perhaps you just need a single character not a byte?
Then just do:

// Character with code 0x00 would be a default value. 
// and indicate that nothing was read/parsed    
string input = Console.ReadLine();
char mainMenuSelection = input.Length > 0 ? input[0] : 0x00;