How to: Explicitly Implement Interface Members (C# Programming Guide)

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：

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()); }}/* Output: Length: 30 Width: 20*/

可靠编程

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• 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//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：System.Console.WriteLine("Length: {0}", dimensions.getLength());
  System.Console.WriteLine("Width: {0}", dimensions.getWidth());
  
  

 

 

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