How do I Implements Parent class Interface in child class

[owais]

Hi,

I have a problem, I want to implements Parent class interface methods in child class. for e.g

-------------- Test1.vb ----------------
Imports System
Imports System.Web.UI
Imports System.Web.UI.W ebControls
Imports System.Globaliz ation

Public Class Test1
Inherits RadioButton
Implements IPostBackDataHa ndler

Public Function LoadPostData(By Val postDataKey As String, ByVal postCollection As System.Collecti ons.Specialized .NameValueColle ction) As Boolean Implements System.Web.UI.I PostBackDataHan dler.LoadPostDa ta

End Function

Public Sub RaisePostDataCh angedEvent() Implements System.Web.UI.I PostBackDataHan dler.RaisePostD ataChangedEvent

End Sub
End Class

-------------------------------------------------

when i compiling this class it gives me error

" Interface 'System.Web.UI. IPostBackDataHa ndler' is already implemented by base class 'System.Web.UI. WebControls.Rad ioButton'."

Please help me in this regard

Thanks
Owais

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[Steve]

"owais" <[e-mail]> wrote in message
news:uS******** *****@TK2MSFTNG P15.phx.gbl...

Hi,

I have a problem, I want to implements Parent class interface methods in
child class. for e.g
<snip> " Interface 'System.Web.UI. IPostBackDataHa ndler' is already implemented by
base class 'System.Web.UI. WebControls.Rad ioButton'."

Just take the implements keyword out of your derived class, and override the
methods in the base class that you want your class to handle.
You do not need the implements keyword in your overriding methods either.

eg:

public Class MyBase
implements SomeInterface

protected overridable sub DoSomething implements
SomeInterface.D oSomething
'do whatever
end sub

end class

public class MyDerived
inherits MyBase

protected overrides sub DoSomething
'do something else instead
end sub

end class
hope this helps

Steve

[owais]

Thanks for the reply.

I made the class according to your instruction

-------------------------------------------------------
Imports System
Imports System.Web.UI
Imports System.Web.UI.W ebControls
Imports System.Globaliz ation

Public Class Test1
Inherits RadioButton

Public Overrides Function LoadPostData(By Val postDataKey As String, ByVal postCollection As System.Collecti ons.Specialized .NameValueColle ction) As Boolean

End Function

Public Overrides Sub RaisePostDataCh angedEvent()

End Sub
End Class
-------------------------------------------------------------

but unfortunately it also gives me the error

"function 'LoadPostData' cannot be declared 'Overrides' because it does not override a function in a base class.
sub 'RaisePostDataC hangedEvent' cannot be declared 'Overrides' because it does not override a sub in a base class."
Thanks
Owais

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[Robin Tucker]

I think in this instance you should declare those methods Overridable and
then in a derived class (child class as you say), you "overrides" the
methods, so:

Public Class Test1
Inherits RadioButton

Public Overridable Function LoadPostData(By Val postDataKey As
String, ByVal postCollection As
System.Collecti ons.Specialized .NameValueColle ction) As Boolean

End Function

Public Overridable des Sub RaisePostDataCh angedEvent()

End Sub
End Class

Public Class Test2
Inherits Test1

Public Overrides Function LoadPostData(By Val postDataKey As String,
ByVal postCollection As System.Collecti ons.Specialized .NameValueColle ction)
As Boolean

End Function

Public Overrides des Sub RaisePostDataCh angedEvent()

End Sub

End Class

"owais" <[e-mail]> wrote in message
news:eZ******** ******@TK2MSFTN GP15.phx.gbl...

Thanks for the reply.

I made the class according to your instruction

-------------------------------------------------------
Imports System
Imports System.Web.UI
Imports System.Web.UI.W ebControls
Imports System.Globaliz ation

Public Class Test1
Inherits RadioButton

Public Overrides Function LoadPostData(By Val postDataKey As String,
ByVal postCollection As
System.Collecti ons.Specialized .NameValueColle ction) As Boolean

End Function

Public Overrides Sub RaisePostDataCh angedEvent()

End Sub
End Class
-------------------------------------------------------------

but unfortunately it also gives me the error

"function 'LoadPostData' cannot be declared 'Overrides' because it does
not override a function in a base class.
sub 'RaisePostDataC hangedEvent' cannot be declared 'Overrides' because it
does not override a sub in a base class."
Thanks
Owais

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[Steve]

"owais" <[e-mail]> wrote in message
news:eZ******** ******@TK2MSFTN GP15.phx.gbl...

but unfortunately it also gives me the error

"function 'LoadPostData' cannot be declared 'Overrides' because it does
not override a function in a base class.
sub 'RaisePostDataC hangedEvent' cannot be declared 'Overrides' because it
does not override a sub in a base class."

Hi owais

I just had a quick look through the docs. The interface is implemented in
the web checkbox class, which is the parent of the radiobutton.
The function is private though so you cannot override it

From the docs....

This member supports the .NET Framework infrastructure and is not intended
to be used directly from your code.

[Visual Basic]
Private Function LoadPostData( _
ByVal postDataKey As String, _
ByVal postCollection As NameValueCollec tion _
) As Boolean Implements IPostBackDataHa ndler.LoadPostD ata
Steve

[owais]

Thanks for the reply. Its amazing ,this code works on C#. I don't know VB.NET and C# both are using same CLR. The code of C# belo

-----------------------------------------------------------

[ToolboxData("<{ 0}:GroupRadioBu tton runat=server></{0}:GroupRadioB utton>")
public class Test1 : RadioButton, IPostBackDataHa ndle

public GroupRadioButto n() : base(

#region Propertie

private string Valu

ge

string val = Attributes["value"]
if(val == null
val = UniqueID
els
val = UniqueID + "_" + val
return val

#endregio

#region Renderin

protected override void Render(HtmlText Writer output

RenderInputTag( output)
private void RenderInputTag( HtmlTextWriter htw

htw.AddAttribut e(HtmlTextWrite rAttribute.Id, ClientID)
htw.AddAttribut e(HtmlTextWrite rAttribute.Type , "radio")
htw.AddAttribut e(HtmlTextWrite rAttribute.Name , GroupName)
htw.AddAttribut e(HtmlTextWrite rAttribute.Valu e, Value)
if(Checked
htw.AddAttribut e(HtmlTextWrite rAttribute.Chec ked, "checked")
if(!Enabled
htw.AddAttribut e(HtmlTextWrite rAttribute.Disa bled, "disabled")

string onClick = Attributes["onclick"]
if(AutoPostBack

if(onClick != null
onClick = String.Empty
onClick += Page.GetPostBac kClientEvent(th is, String.Empty)
htw.AddAttribut e(HtmlTextWrite rAttribute.Oncl ick, onClick)
htw.AddAttribut e("language", "javascript ")

els

if(onClick != null
htw.AddAttribut e(HtmlTextWrite rAttribute.Oncl ick, onClick)
if(AccessKey.Le ngth > 0
htw.AddAttribut e(HtmlTextWrite rAttribute.Acce sskey, AccessKey)
if(TabIndex != 0
htw.AddAttribut e(HtmlTextWrite rAttribute.Tabi ndex,
TabIndex.ToStri ng(NumberFormat Info.InvariantI nfo))
htw.RenderBegin Tag(HtmlTextWri terTag.Input)
htw.RenderEndTa g()
#endregio

#region IPostBackDataHa ndler Member

void IPostBackDataHa ndler.RaisePost DataChangedEven t(

OnCheckedChange d(EventArgs.Emp ty)
bool IPostBackDataHa ndler.LoadPostD ata(string postDataKey,
System.Collecti ons.Specialized .NameValueColle ction postCollection

bool result = false
string value = postCollection[GroupName]
if((value != null) && (value == Value)

if(!Checked

Checked = true
result = true
els

if(Checked
Checked = false

return result
#endregio
}

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