Visual Basic .NET/Logical operators
Logical Operators
[edit | edit source]Not
[edit | edit source]The Not operator returns True when the condition is False. Otherwise, it returns False. Example,
If Not (1 = 2) Then
MessageBox.Show("(1 = 2) is False. So Not False is True")
End If
Condition | Not Condition |
True | False |
False | True |
And
[edit | edit source]The And operator returns True when the conditions of the left and right are True. Otherwise, it returns False. Both conditions are evaluated before the result is returned. Example,
If (1 = 1) And (2 = 2) Then
MessageBox.Show("(1 = 1) is True. (2 = 2) is True. So True And True is True")
End If
Condition1 | Condition2 | Condition1 And Condition2 |
True | True | True |
True | False | False |
False | True | False |
False | False | False |
AndAlso
[edit | edit source]The AndAlso operator returns False when the condition on the left hand side is False. Else, it returns True when the conditions of the left and right are True. Otherwise, it returns False. The condition on the right hand side is never evaluated when that on the left hand side is False. This is called short-circuited logic.
Condition1 | Condition2 | Condition1 AndAlso Condition2 |
True | True | True |
True | False | False |
False | - | False |
Or
[edit | edit source]The Or operator returns True when the condition on either side is True. Otherwise, it returns False. Both conditions are evaluated before the result is returned.
Condition1 | Condition2 | Condition1 Or Condition2 |
True | True | True |
True | False | True |
False | True | True |
False | False | False |
OrElse
[edit | edit source]The OrElse operator returns True when the condition on the left hand side is True. Else, if the condition on the right hand side is True, it returns True. Otherwise, it returns False. The condition on the right hand side is never evaluated when that on the left hand side is True. This is called short-circuited logic.
Condition1 | Condition2 | Condition1 OrElse Condition2 |
True | - | True |
False | True | True |
False | False | False |
Xor
[edit | edit source]The Xor operator returns True when the condition on the left hand side or right hand side is True, but not when both are True. Xor means "Exclusive OR".
Condition1 | Condition2 | Condition1 Xor Condition2 |
True | True | False |
True | False | True |
False | True | True |
False | False | False |