How To correctly set Parameters for Function with LinQ and List<T>?-CodePudding

I am struggling with the paramaters for my IEnumerable<ISeries> Function.

I created an interface AllProperties, which combines all the properties from different classes that I am going to need at some point.

This is my IEnumerable<ISeries> GetDepartments right now:

public IEnumerable<ISeries> GetDepartments()
        {
            IEnumerable<ISeries> series = Employees.GroupBy(x => x.Department).ToList().Select(x => new PieSeries<double>
            {
                Values = new List<double> { x.Count() },
                Name = x.Key,
            });

            return series;
        }

It works perfectly fine, but I'll have to copy/paste the code for each List and Property and I would like to avoid that.

The idea of the function I am trying to create is, that I reference a List and a given property and return an IEnumerable<ISeries>

This is what I got so far:

        public IEnumerable<ISeries> GetEnumerableGroupBy<T,TKey>(List<T> list, Func<AllProperties, TKey> myGroupingProperty) 
        {

            IEnumerable<ISeries> series = list.GroupBy(myGroupingProperty).ToList().Select(x => new PieSeries<double>
            {
                Values = new List<double> { x.Count() },
                Name = x.ToString(),
            });

            return series;
        }

//Calling the function like this
GetEnumerableGroupBy(Employees, x => x.Department);

now I am getting the error, that List<T> does not contain a definition for GroupBy and I don't know how to fix this.

Any help would be greatly appreciated.

CodePudding user response：

You're very close. You don't need the AllProperties interface at all. Instead, just make your function argument the generic T type.

public IEnumerable<ISeries> GetEnumerableGroupBy<T, TKey>(List<T> list, Func<T, TKey> myGroupingProperty)
{
   ...
}

The rest of your code should work just fine.