使用接口:
Sub TestInterface() Dim RectangleObject2 As New RectangleClass2() Dim RightTriangleObject2 As New RightTriangleClass2() ProcessShape2(RightTriangleObject2, 3, 14) ProcessShape2(RectangleObject2, 3, 5) End Sub Sub ProcessShape2(ByVal Shape2 As Shape2, ByVal X As Double, ByVal Y As Double) MessageBox.Show("The area of the object is " & Shape2.CalculateArea(X, Y)) End Sub '使用了接口,就可以通过同一个方法,处理实现了同一接口的不同类
Public Interface Shape2 Function CalculateArea(ByVal X As Double, ByVal Y As Double) As Double End Interface
Public Class RightTriangleClass2 Implements Shape2 Function CalculateArea(ByVal X As Double, ByVal Y As Double) As Double Implements Shape2.CalculateArea ' Calculate the area of a right triangle. Return 0.5 * (X * Y) End Function End Class
Public Class RectangleClass2 Implements Shape2 Function CalculateArea(ByVal X As Double, ByVal Y As Double) As Double Implements Shape2.CalculateArea ' Calculate the area of a rectangle. Return X * Y End Function End Class

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