CODEWITHSUNDEEP
c#.netlinqlambda
Hasan Akgün
Hasan Akgün

Reputation: 465

wrong expression result linq

I want to get records with parentIds. But this Linq expression gave me elements with 0 parentId value.

var orders =
    OrderEquityTransactions.AsParallel().Where(
        o => o.FinancialInstrumentId == financialInstrumentPrice.FinancialInstrumentId &&
            o.ParentId != 0 &&
        o.DebitCredit == "A" ? o.Price >= financialInstrumentPrice.Price : o.Price <= financialInstrumentPrice.Price).ToList();

After some digging I rewrote expression with additional two brackets and problem solved. 

var orders =
    OrderEquityTransactions.AsParallel().Where(
        o => o.FinancialInstrumentId == financialInstrumentPrice.FinancialInstrumentId &&
            o.ParentId != 0 &&
        (o.DebitCredit == "A" ? o.Price >= financialInstrumentPrice.Price : o.Price <= financialInstrumentPrice.Price)).ToList();

What is the reason of this behavior?

Upvotes: 0

Views: 64

Answers (2)

poke
poke

Reputation: 388463

As per Operator precedence and associativity, conditional ANDs have a higher precedence than the conditional operator. So C# evaluates your expresion like this:

(o.FinancialInstrumentId == financialInstrumentPrice.FinancialInstrumentId 
        && o.ParentId != 0 && o.DebitCredit == "A")
    ? o.Price >= financialInstrumentPrice.Price
    : o.Price <= financialInstrumentPrice.Price

Upvotes: 3

Yeldar Kurmangaliyev
Yeldar Kurmangaliyev

Reputation: 34244

Because in the first case it was interpreted as:

o => (o.FinancialInstrumentId == financialInstrumentPrice.FinancialInstrumentId 
   && o.ParentId != 0 && o.DebitCredit == "A") 
  ? o.Price >= financialInstrumentPrice.Price 
  : o.Price <= financialInstrumentPrice.Price

which is absolutely another.

Please, read this article on operator precedence.
Ternary conditional operator has the lower priority than conditional AND.

Upvotes: 4

Related Questions