private void Form1_Load(object sender, EventArgs e)
{
northwindEntities dc = new northwindEntities();
AutoCompleteStringCollection sc = new AutoCompleteStringCollection();
foreach (Customers c in dc.Customers)
{
sc.Add(c.CompanyName);
}
txtCustomer.AutoCompleteCustomSource = sc;
}
private void btnQuery_Click(object sender, EventArgs e)
{
northwindEntities dc = new northwindEntities();
var query = (from c in dc.Customers
where c.CompanyName == txtCustomer.Text
select c).Single().Orders.Select(o => o.OrderID);
if (query.Count() == 0)
{
MessageBox.Show("客戶尚未有訂購記錄!");
dataGridView1.DataSource = null;
}
cboOrders.DataSource = query.ToArray();
}
private void cboOrders_SelectedIndexChanged(object sender, EventArgs e)
{
northwindEntities dc = new northwindEntities();
var query = (from od in dc.Order_Details
select od).ToList().Where(od => od.OrderID == int.Parse(cboOrders.Text));
//===============
decimal subtotal = query.Sum(od => od.UnitPrice * od.Quantity * (1 - (decimal)od.Discount));
lbSubtotal.Text = string.Format("小計:{0}", subtotal.ToString("C"));
//===============
dataGridView1.DataSource = query.Select(od => new
{
訂單編號 = od.OrderID,
//商品編號=od.ProductID,
商品單價 = od.UnitPrice,
訂購數量 = od.Quantity,
優惠折扣 = od.Discount,
小計 = (od.UnitPrice * od.Quantity * (1 - (decimal)od.Discount)).ToString("C"),
}).ToArray();
//dataGridView1.Columns[5].Visible = false;
}
