从未输入的字段中获取 <Ienumerable> 对象C＃Linq

Question

I want a method in my program that returns the resulting of a linq Query, here is the function :

public static IEnumerable<object> ConsultasSQL(int TipoConsulta)
{       
    SQLDataContext DC = new SQLDataContext();
    IEnumerable<object> consulta = (dynamic)null;
    switch(TipoConsulta)
    {
        case 1: // Registro en Linea
             DC = SQLDataContext.GetDataContext("Tiendas", componerCS());
                  consulta = from tienda in DC.Tiendas
                  where tienda.Cod__Tienda == Globales.Tienda
                  select tienda;
            break;

        case 2:// Efectivo_Local
            DC = SQLDataContext.GetDataContext("Formas de Pago",componerCS());
                 consulta = from pagos in DC.Formas_de_Pago
                 where pagos.Efectivo_Local == 1
                 select pagos;
            break;

        case 3: // Productos
                 DC = SQLDataContext.GetDataContext("Item",componerCS());
                 consulta = from Productos in DC.Item
                 select Productos;
            break;

    }

   return consulta.ToList();
}

I called this function in other place of my program like this :

public static void Efectivo_local()
{
    var consulta = ConsultasSQL(3);
   // Globales.IdPagoLocal = consulta.First().ID_Pago;
   //Globales.DesriPagoLocal = consulta.First().ID_Pago;
}

The code works and if I put consulta as a Datagridview datasource it shows me the data , but I have two problems :

1 - if I put datagridview1.datasource = consulta.first() --> Its show me nothing :( 2 - I dont know how to retrieve the value of specific field of consulta.tolist()

As you can see in the picture below , consulta have 144 records and i want to retrieve the field 1 of the second row , its like and array? [1,1] ??

http://i.imgur.com/5xHe8Hi.jpg )

Answer 1

You could add an interface to your data classes. That said, if you know the type you're expecting to get at runtime, why are you using IEnumerable<object> at all? Why not have three separate functions, each of which has a single defined purpose? It would be better OO design, imo.

Answer 2

To get specific value, you have to do casts of value, so change SQLDataContext:

private SQLDataContext DC = new SQLDataContext();
... 
public static IEnumerable<object> ConsultasSQL(int TipoConsulta)
{
    ...
}

And add this code:

var consulta = ConsultasSQL(3) as List<DC.Item.Productos>;
if (consulta != null) {
   datagridview1.datasource = consulta.first();
   Globales.IdPagoLocal = consulta.Find(c => c.id == 123456).ID_Pago;
}

But I suggest you change the code as Jeff Koch says... :-)