How can I create a dynamic Select on an IEnumerable at runtime?

Question

Given that I have an IEnumerable, where T is any object, how can I select a specific property from it, given that I know the name of the o

Answer 1

It is possible to do this using an Expression

e.g.

private class Foo {
    public string Bar { get; set; }
}

private IEnumerable SomeFoos = new List() {
    new Foo{Bar = "Jan"},
    new Foo{Bar = "Feb"},
    new Foo{Bar = "Mar"},
    new Foo{Bar = "Apr"},
};

[TestMethod]
public void GetDynamicProperty() {

        var expr = SelectExpression("Bar");
        var propValues = SomeFoos.Select(expr);

        Assert.IsTrue(new[] { "Jan", "Feb", "Mar", "Apr" }.SequenceEqual(propValues));

    }

public static Func SelectExpression(string fieldName) {

    var param = Expression.Parameter(typeof(TItem), "item");
    var field = Expression.Property(param, fieldName);
    return Expression.Lambda>(field, new ParameterExpression[] { param }).Compile();

}

hth,
Alan.