DeepData with Linq in C#

alef posted on Thursday, November 06, 2008

When I try to run the DeepData example with Linq it fails when executing the following line of code

data = ((DeepData.DTO.OrderDto[])(dal.GetOrders()));

the following error is raised

Unable to cast object of type Csla.Data.SafeDataReader  to type DeepData.DTO.OrderDto

 

In App.Config I added the following:

<add key="OrderData" value="DeepData.DAL.DLinq.OrderData,DeepData.DAL.DLinq"/>

 

 

alef replied on Friday, November 07, 2008

I've found partially a solution. With the modifications below the grid with the orders will be filled in.
But the other grids with LineItems and LineItemDetails stay still empty. I'm alreday 50% happy.
dal.GetOrders must return an object (see abstract method in DeepData.DAL : public abstract object GetOrders())
So GetOrders will cast the SafeDataReader to an object.
And in FetchDto we can cast back the object to a SafeDataReader.
Apparently this is not a problem. But converting a Csla.Data.SafeDataReader to a DeepData.DTO.OrderDto doesn't want to work in C#, but in VB it is not a problem.
Can somebody explain this a little bit? I want to understand the differences between VB and C#.

Below the code modifications:
Project DeepData.DAL.DLinq.csproj
class : OrderData.cs

   public override object GetOrders()
    {
      var q = from o in db.Orders select o;

      IDbCommand command = db.GetCommand(q);
      command.Connection = db.Orders.Context.Connection;
      command.Connection.Open();
      SafeDataReader reader = new SafeDataReader(command.ExecuteReader(CommandBehavior.CloseConnection));
      return reader;
    }

Project DeepData.Library.csproj
class OrderList.da.cs
    private void FetchDto()
    {
      try
      {
        RaiseListChangedEvents = false;
        IsReadOnly = false;
        DeepData.DAL.DataFactory df = new DeepData.DAL.DataFactory();
        SafeDataReader data;
        using (var dal = df.GetOrderDataObject())
        {
          data = new SafeDataReader((IDataReader)dal.GetOrders());
          while (data.Read())
            Add(OrderInfo.GetOrderInfo(data));
        }
      }
      finally
      {
        IsReadOnly = true;
        RaiseListChangedEvents = true;
      }

    }




The other grids with LineItems and LineItemDetails stay empty.
Is the reason maybe the following:
When I compare the VB version and the C# version of DeepData I remark that in VB you have the following classes:
  OrderInfo.da.vb
  LineItemInfo.da.vb
  LineItemDetailInfo.da.vb
but these classes are missing in C#