Question

So, to start, I have seen posts like this: How to find which condition is true without using if statement

It’s not quite what I need, although the idea is pertinent, in that I would like it to be more readable code.

I think Switch is the best bet, but let me explain.

I have this statement:

if (input == string.Empty || typeComboBox.Text == null)
{
    MessageBox.Show("Nothing to encrypt!", "Nothing Selected!");            
    return null;
}

So the idea here is that I used to have this statement broken into two “IF” statements, which isn’t a huge deal, but for readability sake, and my on going effort of reducing code, I wanted to combine the statements into one.

If input is empty, I want the first argument in MessageBox.Show to appear, but not the second.

If typeComboBox.Text is null, I want the second option to appear, but not the first.

If they are both true statements, I want both to appear.

Now, my goal was to have these both done without the use of more than one test or method. Basically, I mean this: if I can find which condition is true and have the resultant data output within the same statement, that would be ideal.

I see switches being an option, and I don’t understand them very well yet, but I think that would require me to make a decision method based on the outcome of this test, and send that outcome to the switch; which wouldn’t be ideal, as I could simply have two if statements and less code.

Is there any way to do this in one statement? It’s not necessary for this specific program, but I want to know for the future.

Thanks!

Answer 1

I am assuming that you started with this code:

if (input == string.Empty)
{
    MessageBox.Show("Nothing to encrypt!");            
    return null;
}

if (typeComboBox.Text == null)
{
    MessageBox.Show("Nothing Selected!");            
    return null;
}

I don’t consider there to be anything wrong with this code at all, and this is probably the most readable. It will perform exactly as many tests as necessary, and no more. Any alternative will result in more tests being performed, even though you may wind up with less code. For example:

if (input == string.Empty || typeComboBox.Text == null)
{
    MessageBox.Show((input == string.Empty) ? "Nothing to encrypt!" : "Nothing Selected!");
    return null;
}

Less lines of code, but in a failure scenario there will be two or three tests performed instead of one or two. It’s also a bit less straightforward.

Terse code is nice, but make it too terse and it becomes harder to maintain. Readability lies somewhere between verbose and terse, and in this case the more verbose code is more readable, in my opinion.

---

Another option is to consider the fact that it would be appropriate to report multiple errors. For that, try code like this:

List<string> errors = new List<string>();

if (input == string.Empty)
{
    errors.Add("Nothing to encrypt.");
}

if (typeComboBox.Text == null)
{
    errors.Add("Nothing selected.");
}

if (errors.Count != 0)
{
    MessageBox.Show(string.Join(" ", errors.ToArray()));
    return null;
}

This is a bit more verbose than your original code, but it will allow all relevant errors to be reported instead of only the first one encountered.