Do you avoid Double-Negative Conditionals in if-statements?

Try to avoid Double-Negative Conditionals in if-statements. Double negative conditionals are difficult to read because developers have to evaluate which is the positive state of two negatives. So always try to make a single positive when you write if-statement.

if (!IsValid)
{
        // handle error
}
else
{
       // handle success
}

if (IsValid)
{
       // handle success
}
else
{
       // handle error
}

if (!IsValid)
{
       // handle error
}

Use pattern matching for boolean evaluations to make your code even more readable!

if (IsValid is false)
{
       // handle error
}