Can we use boolean operator in Delphi XE2 LiveBinding expression?

Question

I am planning to write a Live Binding source expression for TCheckBox:

SourceExpression = '(Checked = False) and (Enabled = True)'

When execute the code, an exception prompted:

Expected EOF - trailing text in expression

Is Delphi XE2 Live Binding support boolean operator?

Answer 1

No, boolean operators are not supported directly.

From the docu :

You can use the following math symbols in your expressions:

• Constants: nil True False Pi
• Arithmetic operators: + - * /
• Logic operators: = <> < <= > >=
• Parentheses, (), to change operator precedence.

But you can use the builtin functions IfAll() , IfAny() and IfThen() instead of and , or and not :

SourceExpression := 'IfAll(IfThen(Checked, False, True), Enabled)'

Or you register your own functions .

I tested this 4 XE4, but it should work for XE2 2.

• A or B : IfAny(A, B)
• A and B : IfAll(A, B)
• not A : IfThen(A, False, True)
• A xor B : IfAll(IfAny(A, B), IfThen(IfAll(A,B), False, True))