使用子集时EF6上下文丢失

Question

Hi I have a Table 'Suppliers' and another 'SupplierPlants' I have both tables bound to DataGridViews via code:

        bsSuppliers = new BindingSource();
        bsSuppliers.DataSource = AppData.Suppliers;
        bsSuppliers.AllowNew = true;
        dgvSuppliers.DataSource = bsSuppliers;
        dgvSuppliers.Refresh();

        bsSuppliersPlants = new BindingSource();
        bsSuppliersPlants.DataSource = AppData.SupplierPlants;
        bsSuppliersPlants.AllowNew = true;
        dgvSupplierPlants.DataSource = bsSuppliersPlants;
        dgvSupplierPlants.Refresh();

The AppData class holds all of my DB entities:

        Db = new PureTrialEntities();

        Db.Suppliers.Load();
        Suppliers = Db.Suppliers.Local;

        Db.SupplierPlants.Load();
        SupplierPlants = Db.SupplierPlants.Local;

Now I have RowEnter event bound for the Supplier DataGridView so that it will only show Plants for the selected Suppliers:

    private void dgvSuppliers_RowEnter(object sender, DataGridViewCellEventArgs e)
    {
        var supplier = ((Supplier)dgvSuppliers.Rows[e.RowIndex].DataBoundItem);
        if (supplier == null)
            return;

        ShowSupplierPlants(supplier.SupplierID);
     }

    private void ShowSupplierPlants(int supplierID)
    {
        var plantData = AppData.SupplierPlants.Where(x => x.SupplierID == supplierID); //Get selected Suppliers Plant Data.
        if (plantData.Any())
            bsSuppliersPlants.DataSource = plantData;
        else
            bsSuppliersPlants.DataSource = new List<SupplierPlant>();

        dgvSupplierPlants.Refresh();
    }

The issue is when I call AppData.Db.SaveChanges(); it will correctly apply all changes to the Suppliers Table but it wont Add new rows for the SupplierPlants table as I have taken a subset of the local db. Do I have to manually manage new rows added for this Table as I am using a subset and not the whole Local db?

Answer 1

You should insert them manually,

Db.SupplierPlants.Add(item);

Detailed information

Hope helps,

Answer 2

just as a FYI i bound the DGV CellEndEdit and just added the newly added line to the context like so:

 private void dgvSupplierPlants_CellEndEdit(object sender, DataGridViewCellEventArgs e)
    {
        var data = ((SupplierPlant)((DataGridView)sender).Rows[e.RowIndex].DataBoundItem); //Get the Data for the edited Row.
        if (AppData.Db.Entry(data).State == EntityState.Detached)
        {
            AppData.SupplierPlants.Add(data);
        }

    }