LINQ JOIN两个表并查看两个列

Question

I Have two tables

tblPhases

And

tblTruck

I JOINED these two but I can't seem to use both columns on both tables.

Phase.cs

public class Phases
{
    public int Id { get; set; }

    public int TruckId { get; set; }
    public virtual RTrucks Truck { get; set; }

    public string Checkin { get; set; }

    public string ChassisPrep { get; set; }

    public string Floor { get; set; }

    public string Body { get; set; }

    public string Paint { get; set; }

    public string Finished { get; set; }

}

RTruck.cs

public class RTrucks
{
    public int Id { get; set; }

    public string ChassisManufacturer { get; set; }

    public string ChassisModel { get; set; }
}

Service.cs

[OperationContract]
    List<Phases> GetPhasesbyTruck(int TruckId);

Service.svc.cs

public List<Phases> GetPhasesbyTruck(int TruckId)
    {
        TruckDb db = new TruckDb();

        List<Phases> r = new List<Phases>();

        var join = from p in db.RTrucks
                   join t in db.Phases
                   on p.Id
                   equals t.TruckId
                   where t.Id == TruckId
                   select p;


        foreach (var item in join)
        {
            r.Add(new Phases()
            {
   //this is not the actual coding but just a demonstration of what is 
   //actually happening                                                                                         
   //    Phases item like Id = tblTruck item like truckId        
            });
        }
        return r;

    }

I cannot call the columns from the tblPhases table only from the tbltrucks table, and also how can I use the Phases.cs and RTruck.cs together in my foreach so I can access both class items?

Answer 1

First of all, following code

var join = from p in db.RTrucks
           join t in db.Phases
           on p.Id equals t.TruckId
           select p;

is enough to make a join between two tables. you do not need to add an extra where clause to it. Secondly, you can either select properties from both tables as mentioned by Arianit in his answer or you can just select Phases as in above query and then you can access Truck through navigation properties like

foreach (var p in join){
    int truckId = p.Truck.Id;
    string chesis = p.Truck.ChassisManufacturer;
    string model = p.Truck.ChassisModel;
}

The benefit of second approach is that you don't need a new class to populate properties from both tables. you can access all information through navigation properties.

Answer 2

try this:

var join = from p in db.RTrucks
           join t in db.Phases
           on p.Id equals t.TruckId
           select new {TruckName = p.TruckName, //depends from your table column name
           PhasesName = t.PhaseName
           };

foreach (var item in join)
{
     Console.WriteLine(item.TruckName + "\t" + item.PhaseName);
 }

Remove the where from your linq