如何将另一个结构隐式转换为我的Type?

时间:2010-06-10 14:50:08

标签: c# .net variable-assignment implicit

因为它是MyClass x = 120;,是否可以创建这样的自定义类? 如果是这样,我该怎么做?

4 个答案:

答案 0 :(得分:4)

不确定这是否是您想要的,但您可以通过实现隐式运算符来实现: http://msdn.microsoft.com/en-us/library/z5z9kes2(VS.71).aspx

答案 1 :(得分:4)

使用隐式运算符通常被认为是一个坏主意,因为它们毕竟是隐含的并且在您的背后运行。调试代码乱丢运算符重载是一场噩梦。也就是说,有这样的事情:

public class Complex
{
    public int Real { get; set; }
    public int Imaginary { get; set; }

    public static implicit operator Complex(int value)
    {
        Complex x = new Complex();
        x.Real = value;
        return x;
    }
}

你可以使用:

Complex complex = 10;

或者你可以重载+运算符

public static Complex operator +(Complex cmp, int value)
{
  Complex x = new Complex();
  x.Real = cmp.Real + value;
  x.Imaginary = cmp.Imaginary;
  return x;
 }

并使用像

这样的代码
complex +=5;

答案 2 :(得分:3)

创建一个隐式运算符:

http://msdn.microsoft.com/en-us/library/z5z9kes2.aspx

例如:

public struct MyStruct // I assume this is what you meant, since you mention struct in your title, but use MyClass in your example. 
{
    public MyClass(int i) { val = i; }
    public int val;
    // ...other members

    // User-defined conversion from MyStruct to double
    public static implicit operator int(MyStruct i)
    {
        return i.val;
    }
    //  User-defined conversion from double to Digit
    public static implicit operator MyStruct(int i)
    {
        return new MyStruct(i);
    }
}

“这是个好主意吗?”值得商榷。隐式转换往往会破坏程序员的公认标准;一般不是一个好主意。但是,如果你正在做一些大型价值库,那么它可能是一个好主意。

答案 3 :(得分:1)

是的,这是一个简短的例子......

  public struct MyCustomInteger
  {
     private int val;
     private bool isDef;
     public bool HasValue { get { return isDef; } } 
     public int Value { return val; } } 
     private MyCustomInteger() { }
     private MyCustomInteger(int intVal)
     { val = intVal; isDef = true; }
     public static MyCustomInteger Make(int intVal)
     { return new MyCustomInteger(intVal); }
     public static NullInt = new MyCustomInteger();

     public static explicit operator int (MyCustomInteger val)
     { 
         if (!HasValue) throw new ArgumentNullEception();
         return Value;
     }
     public static implicit operator MyCustomInteger (int val)
     {  return new MyCustomInteger(val); }
  }