C#中接口成员的显示实现和隐式实现有什么区别？它们各自的作用是什么？

//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。

interface IDimensions

{

    floatgetLength();

    floatgetWidth();

}

class Box : IDimensions

{

    floatlengthInches;

    floatwidthInches;

   Box(float length, float width)

    {

       lengthInches = length;

        widthInches = width;

    }

    //Explicit interface member implementation:

    floatIDimensions.getLength()

    {

       return lengthInches;

    }

    //Explicit interface member implementation:

    floatIDimensions.getWidth()

    {

       return widthInches;

    }

    staticvoid 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());

    }

}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

Length: 30

Width: 20

//////////////////////////////////////////////////////////////////////////////////////////////////////////////////