Question

I came up with this code, which I thought was rather clever (the requirement is that if the selected date is in the past, the TextBoxes should be readonly, otherwise (today’s date or a future date) they should be editable):

bool? setReadOnly = null;

if (SelectedDateIsInThePast() && (!currentlyReadOnly)) {
    setReadOnly = true;
} else if (!SelectedDateIsInThePast() && (currentlyReadOnly)) {
    setReadOnly = false;
}
if (setReadOnlyToTrue.HasValue) {
    foreach (Control ctrl in tableLayoutPanelPlatypus.Controls) {
        if (ctrl is TextBox) {
            tb = (TextBox)ctrl;
            tb.ReadOnly = setReadOnlyToTrue.Value;
        }
    }
}

…but find that nullable bools are “data type non grata” among my compadres.

Is there a non-complicated way to do the same thing (only loop through the controls if the readonly value needs to be changed?). Of course, I could simply set them regardless of whether they needed to be set this way:

if (SelectedDateIsInThePast()) {
    setReadOnly = true;
} else {
    setReadOnly = false;
}
foreach (Control ctrl in tableLayoutPanelPlatypus.Controls) {
    if (ctrl is TextBox) {
        tb = (TextBox)ctrl;
        tb.ReadOnly = setReadOnly;
    }
}

…but I don’t like to perform moot operations, if it’s reasonably possible to avoid them.

Answer 1

Factor the loop into a method, and only call the method in the cases you set setReadOnly:

if (SelectedDateIsInThePast() && (!currentlyReadOnly)) {
    SetReadOnly(true);
} else if (!SelectedDateIsInThePast() && (currentlyReadOnly)) {
    SetReadOnly(false);
}