generic type and cast

[Tommaso Caldarola]

delegate void SomeDelegate<T>() where T : BaseClass;

my_event(object sender, myEventArgs e)
{
//e.Tag object is SomeDelegate<DerivedClass>

SomeDelegate<BaseClass> del = (SomeDelegate<BaseClass>)e.Tag; // *** unable
to cast DerivedClass in BaseClass

}

How I cast (if possible) derived generic type to base generic type?


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[Joanna Carter [TeamB]]

"Tommaso Caldarola" <[email protected]> a écrit dans le message de
[email protected]...

| delegate void SomeDelegate<T>() where T : BaseClass;
|
| my_event(object sender, myEventArgs e)
| {
| //e.Tag object is SomeDelegate<DerivedClass>
|
| SomeDelegate<BaseClass> del = (SomeDelegate<BaseClass>)e.Tag; // ***
unable
| to cast DerivedClass in BaseClass
|
| }
|
| How I cast (if possible) derived generic type to base generic type?

Sorry, this is not possible, you are trying to cast from one bound type to
another, there is no inheritance, even though the parameter type is
inherited.

You can do :

DerivedGenericType<AType> => BaseGenericType<AType>

....because the *generic* type is derived, but :

GenericType<DerivedType> => GenericType<BaseType>

....won't work because they are sibling classes rather than parent/child

Joanna