Using Object Initializers dynamically

Question

I need to pass a list of integers to a stored procedure because Entity Framework takes too long to process the request. I'm using a User Defined Table Type to do this. I'm using EntityFrameworkExtras.EF6 and I've created a stored procedure and Table Type class to help with this. Here are those classes:

namespace MyModel{
using EntityFrameworkExtras.EF6;
[UserDefinedTableType("SelectedActivity")]
public class ChartCountryUDT
{
    [UserDefinedTableTypeColumn(1)]
    public int ID { get; set; }
}

[StoredProcedure("GetCountryChartData")]
public class ChartCountryStoredProcedure
{
    [StoredProcedureParameter(System.Data.SqlDbType.Udt, ParameterName = "ActivityIDs")]
    public List<ChartCountryUDT> ChartCountryUDT { get; set; }



}}

and here is my method to call the stored procedure passing in the Table Type and returning me a List of objects:

public List<ChartCountry> GetCountriesForChart(List<int> activityIDs)
    {
        using (MyEntities ctx = new MyEntities())
        {

            var procedure = new ChartCountryStoredProcedure()
            {
                ChartCountryUDT = new List<ChartCountryUDT>()
                {
                        new ChartCountryUDT() {ID = 1 }
                }

            };

            return (List<ChartCountry>)ctx.Database.ExecuteStoredProcedure<ChartCountry>(procedure);

        }

    }

As you can see in my ChartCountryUDT object initializer, I'm hardcoding one object by setting the ID value to 1. This works fine but I would like to take the activityIDs parameter that is passed in and create new objects in my object initializer for each ID in the activityIDs parameter. Is there any way of looping trough my list of activityIDs and creating new objects in my object initializer for each record? Thanks

Answer 1

You are basically asking how to map (convert) List<int> to List<ChartCountryUDT>, which in LINQ is called projection (select):

var procedure = new ChartCountryStoredProcedure()
{
    ChartCountryUDT = activityIDs.Select(id => new ChartCountryUDT { ID = id }).ToList()
};