Can I use the "Count" property on a Linq result?

Question

I have code like:

var result = from x in Values where x.Value > 5 select x;

Then, I want to check:

if(result.Count > 0) { ... }
else if(result.Count == 1) { ... }
else { throw new Exception(...); }

However, I get errors like:

error CS0019: Operator '==' cannot be applied to operands of type 'method group' and 'int'

Can I do this without writing a foreach over result?

Answer 1

Use result.Count().

Better yet store it

int count = result.Count();

So you aren't iterating over your collection multiple times. Another problem is

if(result.Count() > 0) { ... }
else if(result.Count() == 1) { ... } //would never execute
else { throw new Exception(...); }

Check out the IEnumerable.Any() extension, if you meant for the if to execute if there are any items. Using that extension means you won't be iterating over the collection as you would with IEnumerable.Count().