C# Using Multiple Arguments

Question

This is from a newer C# guy,

I have been back and forth through different questions posed on here but I haven't found anything that answers directly to what I need to know.

I have a console application that I want to pass arguments to, through the command line. This is what I have so far and it's working for a single argument, now I got to add another but I can't seem to figure out where to start.

static void Main(string[] args)
{
    if (args == null || args.Length== 0)
    {
        Console.WriteLine("that's not it");
        help();
    }
    else
    {
        for (int i = 0; i < args.Length; i++)
        {
            backupfolder = args[i];
        }
        checks();
    }
}

If I take everything out of my else statement how can I set what the args are and assign? Will the below work ?

static void Main(string[] args)
{
    if (args == null || args.Length== 0)
    {
        Console.WriteLine("that's not it");
        help();
    }
    else
    {
        string backupfolder = args[0];
        string filetype = args[1];
        checks();
    }
}

Answer 1

You need to check the length of the args array before attempting to retrieve values from it:

static void Main(string[] args)
{
    // There must be at least 2 command line arguments...
    if (args == null || args.Length < 2)
    {
        Console.WriteLine("that's not it");
        help();
    }
    else 
    {
        string backupfolder = args[0]; 
        string filetype = args[1];
        checks();
    }
}

Another option, if you want to allow passing only some of the expected arguments:

static void Main(string[] args)
{
    // There must be at least 1 command line arguments.
    if (args == null || args.Length < 1)
    {
        Console.WriteLine("that's not it");
        help();
    }
    else 
    {
        // You already know there is at least one argument here...
        string backupfolder = args[0]; 
        // Check if there is a second argument, 
        // provide a default value if it's missing
        string filetype = (args.Length > 1) ? args[1] : "" ;
        checks();
    }
}