Simplify Complicated If statements

Question

Well, I have a Form that receives the Employee's level and enable some options depending on his level using a bunch of Checkboxes. However the problem i am facing is that for my application's logic there is specific level range for every option to be enabled so i created an Ugly IF range checking statements that i am sure there is a better way to achieve.

CODE:

if (level >= 1 && level < 3) {
    _items[0].Enabled = true;
    _items[1].Enabled = false;
    _items[2].Enabled = false;
    _items[3].Enabled = false;
    _items[4].Enabled = false;
    _items[5].Enabled = false;
    _items[6].Enabled = false;
    _items[7].Enabled = false;
}
else if (level >= 3 && level < 5) {
    _items[0].Enabled = true;
    _items[1].Enabled = true;
    _items[2].Enabled = false;
    _items[3].Enabled = false;
    _items[4].Enabled = false;
    _items[5].Enabled = false;
    _items[6].Enabled = false;
    _items[7].Enabled = false;
}
else if (level >= 5 && level < 7) {
    _items[0].Enabled = true;
    _items[1].Enabled = true;
    _items[2].Enabled = true;
    _items[3].Enabled = false;
    _items[4].Enabled = false;
    _items[5].Enabled = false;
    _items[6].Enabled = false;
    _items[7].Enabled = false;
}
else if (level >= 7 && level < 9) {
    _items[0].Enabled = true;
    _items[1].Enabled = true;
    _items[2].Enabled = true;
    _items[3].Enabled = true;
    _items[4].Enabled = false;
    _items[5].Enabled = false;
    _items[6].Enabled = false;
    _items[7].Enabled = false;
}
else if (level >= 9 && level < 11) {
    _items[0].Enabled = true;
    _items[1].Enabled = true;
    _items[2].Enabled = true;
    _items[3].Enabled = true;
    _items[4].Enabled = true;
    _items[5].Enabled = false;
    _items[6].Enabled = false;
    _items[7].Enabled = false;
}
else if (level >= 11 && level < 13) {
    _items[0].Enabled = true;
    _items[1].Enabled = true;
    _items[2].Enabled = true;
    _items[3].Enabled = true;
    _items[4].Enabled = true;
    _items[5].Enabled = true;
    _items[6].Enabled = false;
    _items[7].Enabled = false;
}
else if (level >= 13 && level < 15) {
    _items[0].Enabled = true;
    _items[1].Enabled = true;
    _items[2].Enabled = true;
    _items[3].Enabled = true;
    _items[4].Enabled = true;
    _items[5].Enabled = true;
    _items[6].Enabled = true;
    _items[7].Enabled = false;
}
else if (level >= 15 && level < 17) {
    _items[0].Enabled = true;
    _items[1].Enabled = true;
    _items[2].Enabled = true;
    _items[3].Enabled = true;
    _items[4].Enabled = true;
    _items[5].Enabled = true;
    _items[6].Enabled = true;
    _items[7].Enabled = true;
}

Answer 1

You can simplify this with a little math:

int on = (level+1)/2;
for (int i = 0 ; i != 8 ; i++) {
    _items[i].Enabled = (i < on);
}

The first line converts a number in the range from 1 to 16, inclusive, to a number in the range from 1 to 8, inclusive. Then the loop goes through all items, and enables as many of them as is indicated by the value of the on variable computed earlier.

Answer 2

You (might) lose performance, but its arguably more readable. Choose your poison! The performance difference depends on how often this is called.

if(level >= 1) {
    _items[0].Enabled = level >= 1;
    _items[1].Enabled = level >= 3;
    _items[2].Enabled = level >= 5;
    _items[3].Enabled = level >= 8;
    _items[4].Enabled = level >= 9;
    _items[5].Enabled = level >= 11;
    _items[6].Enabled = level >= 13;
    _items[7].Enabled = level >= 15;
}