linq从函数返回IEnumerable <{Object，Object}>

Question

I wish to do something like the following in my data layer

public IEnumerable<{string,int}> ListIngredients()
        {
            return from i in RecipeIngredients select new {i.Ingredient.Name, i.Quantity};
        }

this obviously doesnt work. c# will only let me return IEnumerable and i wish to expose the structure.

Answer 1

You can't do this using anonymous types. What you're after is the Tuple type from .NET 4.0 - you'd write:

public IEnumerable<Tuple<string,int>> ListIngredients()
{
    return RecipeIngredients.Select(i => Tuple.Create(i.Ingredient.Name,
                                                      i.Quantity));
}

You can fairly easily create your own equivalent of course, if you can't use .NET 4.0.

Answer 2

May I suggest that you create a RecipeIngredient class (if you haven't already) that you can return from this method in the form of IEnumerable<RecipeIngredient>?

This will solve your problem, and at the same time, make sense.