Newbie LINQ Question: Is Paging in LINQ Queries Possible?

Question

Is it possible to using "paging" functionality in Linq queries? Let's say I have some XML like this:

<Root>
    <BetaSection>
        <Choices>
            <SetA>
                <Choice id="choice1">Choice One</Choice> 
                <Choice id="choice2">Choice Two</Choice>
                <Choice id="choice3">Choice Three</Choice>
                .
                .
                .
                <Choice id="choice48">Choice Forty-Eight</Choice>
                <Choice id="choice49">Choice Forty-Nine</Choice>
                <Choice id="choice50">Choice Fifty</Choice>
            </SetA>
        </Choices>
    </BetaSection>
</Root>

If I wanted to implement paging functionality, would I be able to provide an offset to a LINQ query such that I could start at the 11th element and end on the 20th element? If so, would the query be any different if the data was a list of objects instead of XML?

Answer 1

var q = from X in Choices.Skip((page-1)*pageSize).Take(pageSize)
        select X;

Now, if you need a where clause in it, it gets a bit trickier:

var q = (from X in Choices
         where x.SomeField == SomeValue
         select X).Skip((page-1)*pageSize).Take(pageSize);

Answer 2

Take a look to the Queryable.Skip and Queryable.Take methods.

Also see this useful extension methods for paging,

with that methods you can do this like this:

List<string> names = new List<string>();
names.AddRange(new string[]{"John","Frank","Jeff","George","Bob","Grant", "McLovin"});

foreach (string name in names.Page(2, 2))
{
    Console.WriteLine(name);
}