示例
' Sometimes we don't need to evaluate all the conditions in an if statement's boolean check.
' Let's suppose we have a list of strings:
Dim MyCollection as List(Of String) = New List(of String)()
' We want to evaluate the first value inside our list:
IfMyCollection.Count> 0 And MyCollection(0).Equals("Somevalue")
Console.WriteLine("Yes, I've found Somevalue in the collection!")
End If
' If MyCollection is empty, an exception will be thrown at runtime.
' This because it evaluates both first and second condition of the
' if statement regardless of the outcome of the first condition.
' Now let's apply the AndAlso operator
IfMyCollection.Count> 0 AndAlso MyCollection(0).Equals("Somevalue")
Console.WriteLine("Yes, I've found Somevalue in the collection!")
End If
' This won't throw any exception because the compiler evaluates just the first condition.
' If the first condition returns False, the second expression isn't evaluated at all.
