c# - The Include path expression must refer to a navigation property defined on the type.in eager loading

Question

I try to include anonymous type like this : I want all incomelist attributes in addition to CompanyTitle ,PeriodTypeName )

 var incomeList = ctx.IncomeLists.Include(i => new
                {
                    CompanyTitle = i.CompanyId.ToString() + "/" + i.Company.CompanyName,
                    PeriodTypeName = i.ListPeriods.Select(lp => lp.PeriodType.PeriodTypeName)
                }).ToList()

---

My model section like this :

but i get the following exception :

The Include path expression must refer to a navigation property defined on the type. Use dotted paths for reference navigation properties and the Select operator for collection navigation properties. Parameter name: path

The result should be the datasource to Gridview.

Answer 1

You cannot use Include to select data like this. Include is used to load related data. You should load your entities using Include then select what you want. Remember to remove .ToString() from CompanyId. EF will do it for you. Your query should look like this:

var incomeList = ctx.IncomeLists
    .Include(i => i.Company)
    .Include(i => i.ListPeriods.Select(lp => lp.PeriodType))
    .Select(i => new 
    {
        CompanyTitle =  i.CompanyId + "/" + i.Company.CompanyName,
        PeriodTypeNames = i.ListPeriods.Select(lp => lp.PeriodType.PeriodTypeName)
    })
    .ToList();