On 16/2/07, Jonathan Heizer <[EMAIL PROTECTED]> wrote:
Hey all,
I am trying to reuse a bunch of Class members, properties, and functions
that are shared across multiple classes. Each of these classes already
inherit form a web control so I can not create a base class supporting the
function since .Net does not support multiple inheritance. Right now each
Inherited class has a complete copy of this code that makes it hard to make
changes to it.
So invision...
MyControl1--\ /---BaseControl1
MyControl2--->Common Code Class<----BaseControl2
MyControl3--/ \---BaseControl3
What I really need is multiple inheritance...
Public Class MyLabel
Inherits System.Web.UI.WebControls.Label)
Inherits MyCommonStuff
End Class
Since so many of these are shared properties and members using basic
interfaces would not really save that much code space. What I was trying to
do is mix in generics and do something along these lines...
Public Class MyBaseControl(Of t)
Inherits t
Class members...
Functions...
Properties...
End Class
Public Class MyLabel
Inherits MyBaseControl(Of System.Web.UI.WebControls.Label)
End Class
Public Class MyTextbox
Inherits MyBaseControl(Of System.Web.UI.WebControls.Textbox)
End Class
So what I need is to somehow make my intermediate class inherit the base
control of my choice at runtime based on the type passed through the
generic. Is anything like this possible? I have not had any luck so far.
Thanks for any help,
The best I came up with:
Public Interface MyBaseInterface(Of T As System.Web.UI.WebControls.WebControl)
Sub SomeAdditional(ByVal a As T, ByRef b As T)
End Interface
Public Class MyBaseClass(Of T As {MyBaseInterface(Of T),
System.Web.UI.WebControls.WebControl})
Shared Sub SomeAdditional(ByVal Base As T, ByVal a As T, ByRef b As T)
' Infinite recursion, but good enough as an example
Base.SomeAdditional(a, b)
End Sub
End Class
Public Class MyLabel
Inherits System.Web.UI.WebControls.Label
Implements MyBaseInterface(Of MyLabel)
' Boilerplate
Public Sub SomeAdditional(ByVal a As MyLabel, ByRef b As MyLabel)
Implements MyBaseInterface(Of MyLabel).SomeAdditional
MyBaseClass(Of MyLabel).SomeAdditional(Me, a, b)
End Sub
End Class
Public Class MyTextbox
Inherits System.Web.UI.WebControls.TextBox
Implements MyBaseInterface(Of MyTextbox)
' Boilerplate
Public Sub SomeAdditional(ByVal a As MyTextbox, ByRef b As
MyTextbox) Implements MyBaseInterface(Of MyTextbox).SomeAdditional
MyBaseClass(Of MyTextbox).SomeAdditional(Me, a, b)
End Sub
End Class
Effectively you're implementing multiple inheritance manually... The
code in the boilerplate routines just calls MyBaseClass where the
detailed code goes. The IDE helps fill out the routine signatures in
the "Boilerplate" code when you complete the Class Implements line.
Not sure if that helps...
Regards,
Mark Hurd, B.Sc.(Ma.)(Hons.)
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