Boolean variables and three-state CheckBoxes: How best to do type conversion?

Question

This is in VB6 (may also apply to VB.net)

CheckBoxes can have three states (Checked, Unchecked, Greyed).

But I'm using them to set boolean variables (MuteSound, etc.) This is definitely a value that has only two states. Unfortunately, the Checked and Unchecked don't correspond to a True/False value.

So, I can't have:

bMuteSound=ChkMute.value .......... If bMuteSound then blah blah

Two options: 1. Force the value when setting/reading the Checkbox.value to be boolean:

bMuteSound=Checkbox.value=Checked .....

Checkbox.value=ConvertBooleanToCheckBox

Answer 1

Does the boolean variable have a default value? If so, then just don't change the variable if the box is greyed and change it to the correct value if it isn't greyed.

Answer 2

bMuteSound = abs(chkMute.Value)
chkMute.Value = abs(bMuteSound)

Answer 3

in a general sense a checkbox could be also be greyed out and checked thus you have 4 possible cases just use 2 booleans, in terms of separation your processing code needs to know nothing of checkboxes and thus should not be passing around a greyed or non greyed state but only the active or inactive state.

Answer 4

Looks simple enough to me:

Dim tsValue As VbTriState

'Conversions
tsValue = -Check1.Value
Check1.Value = -tsValue