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Trivial lambdas in LINQ

Edit: Despite the top positions, I don't think this is a good question (see various comments). Sorry for wasted space, but unfortunately I don't have enough reputation to delete my own post.

Is there a better way to create a lambda (or perhaps a predicate or expression that is not a lambda) that returns either 1) A single argument unchanged, or 2) a constant value? Sometimes I come across when using LINQ where the underlying LINQ extension method requires Func<x,y>

, but I only need an input argument or constant.

In a two-year-old question, Jon Skeet argued that there is no shorthand for a function (see LINQ Identity Function? ). Does the same apply to constant expression? Has (or will) change anything (ed) with .NET 4.5 or C # 5?

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2 answers


you don't need to provide a predicate for the method Count 



.Count()
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If you were looking for some kind of lambda constant, a regular method would be the closest candidate. Let's say it requires <<20> and you want it to return it true

anyway. Instead of writing, collection.SomeLinqMethod(s => true)

you can create a static class with appropriate methods

public static class Expressions
{
    public static bool True(string s)
    {
        return true;
    }
}

Then you write



var result = collection.SomeLinqMethod(Expressions.True);

You can also have common methods

public static bool True<T>(T item)
{
    return true;
}
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