Re: Help with linq

On Thu, 11 Jun 2009 15:21:38 -0700, Julie <jules@invalid.invalid> wrote:


That depends a bit on the exact structure of the code, which you don't
show. But, assuming there's nothing too obstrusive going on, something
like this should work:

    int Qty(Func<MyElement, bool> condition)
    {
        return MyData.Count(condition);
    }

Assume MyData implements IEnumerable<MyElement>. In other words, just
replace "MyElement" with whatever type each element of MyData actually is.

Then in whatever code you want to use the method, you could call it like
this:

    int result = Qty(x => x.Item1 == 1);

Alternatively, keep the methods named "Qty1", "Qty2", etc. and re-write
them to call Qty():

    int Qty1()
    {
        return Qty(x => x.Item1 == 1);
    }

Or, you could go straight to the source, and just call
Enumerable.Count() directly:

    int result = MyData.Count(x => x.Item == 1);

If the property you're checking is always compared to "1", as your
example suggests, you can fold the comparison into the helper method
instead of making the caller provide it:

    int Qty(Func<MyElement, int> funcGetProperty)
    {
        return MyData.Count(x => funcGetProperty(x) == 1);
    }

Then call as so:

    int result = Qty(x => x.Item1);

Mix and match the above variations to suit your needs. :)

Note that in all of the above examples, there's no need to write a LINQ
query. The Enumerable.Count() extension method includes an overload
that provides the same filtering behavior you're using the LINQ query to
do.

Pete