本示例声明一个 接口IDimensions
和一个类 Box
,该类显式实现接口成员 getLength
和 getWidth
。通过接口实例 dimensions
访问这些成员。
示例
C# | ![]() |
---|---|
interface IDimensions { float getLength(); float getWidth(); } class Box : IDimensions { float lengthInches; float widthInches; Box(float length, float width) { lengthInches = length; widthInches = width; } // Explicit interface member implementation: float IDimensions.getLength() { return lengthInches; } // Explicit interface member implementation: float IDimensions.getWidth() { return widthInches; } static void Main() { // Declare a class instance box1: Box box1 = new Box(30.0f, 20.0f); // Declare an interface instance dimensions: IDimensions dimensions = (IDimensions)box1; // The following commented lines would produce compilation // errors because they try to access an explicitly implemented // interface member from a class instance: //System.Console.WriteLine("Length: {0}", box1.getlength()); //System.Console.WriteLine("Width: {0}", box1.getwidth()); // Print out the dimensions of the box by calling the methods // from an instance of the interface: System.Console.WriteLine("Length: {0}", dimensions.getLength()); System.Console.WriteLine("Width: {0}", dimensions.getWidth()); } } |
输出
Length: 30 Width: 20 |
可靠编程
-
请注意 Main 方法中下列代码行被注释掉,因为它们将产生编译错误。显式实现的接口成员不能从类实例访问:
C# 复制代码
//System.Console.WriteLine("Length: {0}", box1.getlength()); //System.Console.WriteLine("Width: {0}", box1.getwidth());
-
还请注意,Main 方法中的下列代码行成功输出框的尺寸,因为这些方法是从接口实例调用的:
C# 复制代码
System.Console.WriteLine("Length: {0}", dimensions.getLength()); System.Console.WriteLine("Width: {0}", dimensions.getWidth());