Abstracts: can I do better than this?
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Is the casting required at all? Even if SetDevice is overloaded for each type there shouldn't be a problem should there? And if not, then you still don't need to cast to each type. Edit: I just tried it and I see the problem. More information about SetDevice would be helpful. And, as Luc said, use
israther than comparing types. Edit: Or perhaps SetDevice should handle determining which type of device it was passed:private static void
SetDev
(
DevBase Dev
)
{
System.Console.WriteLine ( "DevBase" ) ;if ( Dev is Dev1 ) SetDev ( (Dev1) Dev ) ; else if ( Dev is Dev2 ) SetDev ( (Dev2) Dev ) ; return ;}
modified on Wednesday, December 30, 2009 2:01 PM
I have a form with device information for for each type of device. Most of the information is similar, so I'm sharing a single form, using
SetDevice()to setup fields and controls specific to each derived device type. (right now, all SetDevice methods are inside the form, not the Device classes).SelectedDeviceis instantiated as aDevice, then cast to whichever derived class is appropriate. The cast is necessary because at compile-time,SelectedDeviceis just aDevice, but at run-time will have a specific derived type. -
I have a form with device information for for each type of device. Most of the information is similar, so I'm sharing a single form, using
SetDevice()to setup fields and controls specific to each derived device type. (right now, all SetDevice methods are inside the form, not the Device classes).SelectedDeviceis instantiated as aDevice, then cast to whichever derived class is appropriate. The cast is necessary because at compile-time,SelectedDeviceis just aDevice, but at run-time will have a specific derived type.I wonder whether or not
dynamics in C# 4 will do it. -
Is the casting required at all? Even if SetDevice is overloaded for each type there shouldn't be a problem should there? And if not, then you still don't need to cast to each type. Edit: I just tried it and I see the problem. More information about SetDevice would be helpful. And, as Luc said, use
israther than comparing types. Edit: Or perhaps SetDevice should handle determining which type of device it was passed:private static void
SetDev
(
DevBase Dev
)
{
System.Console.WriteLine ( "DevBase" ) ;if ( Dev is Dev1 ) SetDev ( (Dev1) Dev ) ; else if ( Dev is Dev2 ) SetDev ( (Dev2) Dev ) ; return ;}
modified on Wednesday, December 30, 2009 2:01 PM
PIEBALDconsult wrote:
Or perhaps SetDevice should handle determining which type of device it was passed.
Wouldn't that mean creating a big
SetDeviceto handle all types, and just move the same code intoSetDevice? Even if the code is a little less ugly thanks tois. Molly -
PIEBALDconsult wrote:
Or perhaps SetDevice should handle determining which type of device it was passed.
Wouldn't that mean creating a big
SetDeviceto handle all types, and just move the same code intoSetDevice? Even if the code is a little less ugly thanks tois. MollyAfaik, the 'is' keyword is not fully equal to x.GetType() == typeof(y) . Let's say I have: class A class B:A (B inheriting from A) Then following (pseudo-)code:
b = new B();
b is Areturns true and
b = new B();
b.GetType() == typeof(A)returns false. The latter option checks for an exact type match.
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Afaik, the 'is' keyword is not fully equal to x.GetType() == typeof(y) . Let's say I have: class A class B:A (B inheriting from A) Then following (pseudo-)code:
b = new B();
b is Areturns true and
b = new B();
b.GetType() == typeof(A)returns false. The latter option checks for an exact type match.
Paul89 wrote:
b = new B();
b.GetType() == typeof(A);The above test the immediate types
A.GetType() != B.GetType() && B.GetType() != A.GetType()for a better understanding try this:b = new B();
a = new A();typeof(A).ToString();
typeof(B).toString();a.GetType().toString();
b.GetType().toString();However this works like the is keyword:
B.IsSubclassOf(A)returns true -or-A.IsAssignableFrom(B)returns true On the is key word: 'An is expression evaluates to true if the provided expression is non-null, and the provided object can be cast to the provided type without causing an exception to be thrown.'modified on Wednesday, December 30, 2009 2:42 PM
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Afaik, the 'is' keyword is not fully equal to x.GetType() == typeof(y) . Let's say I have: class A class B:A (B inheriting from A) Then following (pseudo-)code:
b = new B();
b is Areturns true and
b = new B();
b.GetType() == typeof(A)returns false. The latter option checks for an exact type match.
Thanks! I think
isworks for the code I've got today, but you probably saved me from myself on some future project. Molly -
I know I'm missing something simple. I have a base class, Device, and a bunch of derived classes Dev1, Dev2... Depending on the type of device active at the moment, I have an abstract method for each derived type. Deciding which to use leads me to:
if (SelectedDevice.GetType() == typeof(Dev1))
{
SetDevice((Dev1)SelectedDevice);
}
else if (SelectedDevice.GetType() == typeof(Dev2))
{
SetDevice((Dev2)SelectedDevice);
}
else if ...It works, but it just feels ugly. Molly
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Thanks! I think
isworks for the code I've got today, but you probably saved me from myself on some future project. MollyOr maybe not! :laugh:
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Or maybe not! :laugh:
Who goes 400 pages deep (as of today) into a forum just to rub it in? :sigh:
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Who goes 400 pages deep (as of today) into a forum just to rub it in? :sigh:
That'd be me. :-D But I took a shortcut -- I saw on your profile that you had only posted a few questions, I checked those few. I didn't actually know I'd find this.