14. 3-1. null許容型(4)
null許容型を宣言する
C#:
int? number;
Nullable<int> number;
VB.NET:
Dim number As Integer? 'VB2008以降
Dim number As Nullable(Of Integer)
15. 3-1. null許容型(5)
null許容型を使う(C#)
int? number = 1;
number = number + 1 //2
number = null
if (number == null){ //true
number = number + 1 //null
}
16. 3-1. null許容型(6)
null許容型を使う(VB.NET)
Dim number As Integer? = 1;
number = number + 1 //2
number = Nothing
If number Is Nothing Then //True
number = number + 1 //Nothing
End If
23. 3-2. ジェネリックコレクション(6)
ジェネリックコレクションを使う(VB.NET)
Dim list As List(Of String) = New List(Of String)
list.Add("a")
list.Add("b")
For i As Integer 0 To list.Count-1
Console.WriteLine("{0}", list(i).ToUpper()) //A, B
Next
31. 3-3. LINQ(8)
LINQを使う(VB.NET)
Dim list As List(Of Integer)
= New List(Of Integer) From {1, 2, 3, 4, 5, 6};
IEnumerable(Of Integer) query
= list.Where(Function(x)=>x mod 2 = 0);
For Each number As Integer In list
Console.WriteLine("{0}", number ) '2 ,4, 6
Next