User-defined conversion operator from base class

Question

Introduction

I am aware that \"user-defined conversions to or from a base class are not allowed\". MSDN gives, as an explanation to this rule, \"You

Answer 1

Honestly, I think the original request is being misunderstood.

Consider the simple situation where a base class is just serving as a grouping of related classes.

Ex:

class Parent ...
class Child1 : Parent ...
class Child2 : Parent ...

Where the programmer knows how to explicitly convert from one child class to another.

The Parent class can be used, for example, in:

Dictionary

What I think the original request is asking for is:

How to be able to code:

Class1 v1 = ...
Class2 v2 = ...

v1 = v2;

Where inside Parent there is explicit code to do the conversion from Class2 to Class1 objects.

I have this exact situation in my code.

The best I managed to do was to add a property to Parent class that knows how to do the conversion and returns the proper typed object.

This forces me to write my code:

v1 = v2.AsClass1;

Where the property AsClass1 in Parent knows how to do the actual conversion from Class2 to Class1.

Honestly this is a code kludge (its ugly; detracts from from simplicity, can make expressions ridiculously long, obfuscates, and most annoyingly it lacks elegance) but its the best I could come up with.

And, yes, you guessed it, the Parent class also includes the AsClass2 method :-)

All I wanted to do was:

v1 = v2;

and have the compiler silently invoke the method I specified to do the conversion.

I really don't understand why the compiler does support this :-(

In my mind this is really no different then:

int v1;
decimal v2;
. . .
v1 = (int)v2;

The compiler knows to silently invoke some built-in conversion method.