Using overloaded operator== in a generic function
- by Dimitri C.
Consider the following code:
class CustomClass
{
public CustomClass(string value)
{ m_value = value; }
public static bool operator==(CustomClass a, CustomClass b)
{ return a.m_value == b.m_value; }
public static bool operator!=(CustomClass a, CustomClass b)
{ return a.m_value != b.m_value; }
public override bool Equals(object o)
{ return m_value == (o as CustomClass).m_value; }
public override int GetHashCode()
{ return 0; /* not needed */ }
string m_value;
}
class G
{
public static bool enericFunction1<T>(T a1, T a2) where T : class
{ return a1.Equals(a2); }
public static bool enericFunction2<T>(T a1, T a2) where T : class
{ return a1==a2; }
}
Now when I call both generic functions, one succeeds and one fails:
var a = new CustomClass("same value");
var b = new CustomClass("same value");
Debug.Assert(G.enericFunction1(a, b)); // Succeeds
Debug.Assert(G.enericFunction2(a, b)); // Fails
Apparently, G.enericFunction2 executes the default operator== implementation instead of my override. Can anybody explain why this happens?
