CODEWITHSUNDEEP
c#reflectionlambda.net-corefunc
Lucas Freitas
Lucas Freitas

Reputation: 1038

Func<TIn, TResult> On generic linq

I've a list of strings.

List<string> myData = new List<string>
            {
                "abcdefghi1",
                "abcdefghi2"
                "abcdefghi3"
            };

If I manually made the following LINQ, it works perfectly.

var myObjectList = (from s in myData 
                    select new myObject
                    {
                        Prop1 = s.Substring(0,3),
                        Prop2 = s.Substring(4,1)...
                    }).ToList();

When I check the "select new myObject" type, it's a Func<string, T>.

If I create the follow method

List<T> getMyObjects(List<string> myData, Func<string, T> selector) where T : class 
{
    return (from s in myData select selector).ToList();
}

And call it like

var myObjectList = getMyObjects(data, 
                      value => new myObject 
                      {
                        Prop1 = value.Substring(0,3),
                        Prop2 = value.Substring(4,1)
                      });

It returns a list of {System.Func<string, MyObject>} instead of a list of

Any idea on how to accomplish that ?

Br,

Upvotes: 0

Views: 60

Answers (1)

Jonathon Chase
Jonathon Chase

Reputation: 9704

You're selecting the mapping function instead of the result of using it to map.

List<T> getMyObjects(List<string> myData, Func<string, T> selector) where T : class 
{
    return (from s in myData select selector).ToList();
}

should likely be

List<T> getMyObjects(List<string> myData, Func<string, T> selector) where T : class 
{
    return (from s in myData select selector(s)).ToList();
    //                                      ^^^ get the result of your selector delegate against the string.
}

Which, as @Camilo Terevinto points out, can be further simplified to:

List<T> getMyObjects(List<string> myData, Func<string, T> selector) where T : class 
{
    return myData.Select(selector).ToList();
}

Upvotes: 2

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