よろしくお願いします。
C# で記述したLINQ to SQL を VB に変換しようと思っていますが、一部エラーになってしまいます。
DataClasses.dbmlは、設定済みで、C#では、正常に実行されます。
db = new DataClassesDataContext();
db.DeferredLoadingEnabled = false;
var customers = from c in db.Customers
where c.City == "London"
select c;
var orders = (from o in db.Orders
where o.Customers.City == "London"
select o).ToList();
StringBuilder sb = new StringBuilder();
foreach (var c in customers)
{
sb.AppendFormat("<b>Customer ID: {0}</b><br/>", c.CustomerID);
// Run a Count(*) query instead of SELECT *
sb.AppendFormat("Orders (using c.Orders.Count) : {0}<br/>", c.Orders.Count());
sb.AppendFormat("Orders (using orders.Count(...)) : {0}<hr/>", orders.Count(o => o.CustomerID == c.CustomerID));
foreach (var o in orders)
{
if (o.CustomerID == c.CustomerID)
sb.AppendFormat("{0}<br/>", o.OrderID);
}
}
Results.Text = sb.ToString();
ここまでは、変換してみましたが、orders.Countのところで、「エラー 1 'Public ReadOnly Property Count As Integer' には引数がないため、戻り値の型をインデックス化できません。」のエラーになってしまいます。
Dim db As New DataClassesDataContext
db.DeferredLoadingEnabled = False
Dim customers = From c In db.Customers
Where c.City = "London"
Select c
Dim orders = (From o In db.Orders
Where o.Customers.City = "London"
Select o).ToList()
Dim sb As StringBuilder = New StringBuilder()
For Each c In customers
sb.AppendFormat("<b>Customer ID: {0}</b><br/>", c.CustomerID)
sb.AppendFormat("Orders (using c.Orders.Count) : {0}<br/>", c.Orders.Count())
sb.AppendFormat("Orders (using orders.Count(...)) : {0}<hr/>", orders.Count(Function(o) o.CustomerID = c.CustomerID))
For Each o In orders
If o.CustomerID = c.CustomerID Then
sb.AppendFormat("{0}<br/>", o.OrderID)
End If
Next
Next
Results.Text = sb.ToString()
