Question

Below is how far I made it. I need to send Expression<Func<T, string>> as the parameter instead of Func<T,string> to the Get function, and still have Select() work. Is this easily possible? This is formatted for LinqPad.

void Main()
{
    // Setup sample data in wholelist
    var wholelist = new List<Example>();
    for (var a = 0; a < 10; a++)
    {   var t = new Example { id = a.ToString(), name = a.ToString() };
        wholelist.Add(t);
    }

    // Do the real work
    var names = Get<Example>( wholelist, p => p.name );
    // LinqPad shows content
    names.Dump();
}

public class Example
{
    public string id {get;set;}
    public string name {get;set;}
}

public static List<string> 
    Get<T>(IEnumerable<T> source, Func<T, string> selector)
{    
    var list = source.Select<T,string>(selector).ToList();
    return list;
}

The why is because we have a lot of functions already calling this one with Expression<Func<T,string>>.

Answer 1

Have you tried expression.Compile?

public static List<string> Get<T>(IEnumerable<T> source, Expression<Func<T, string>> selector)
{
    var list = source.Select<T, string>(selector.Compile()).ToList();
    return list;
}