Cloning a derived control

16 Apr 2005 8:11 PM

Charlie

I want to clone an object that is inherited from Panel. I am using
Serialization, but that is not working because Panel is not Serializable.

I have also tried putting the object into a one member array, then using
Array.Copy to copy the item to multiple members of a second array, but I
cannot get that to work either. Each copied member of the new array has the
same handle as the original object.

Is there an alternate way to clone an object without creating additional
copies as New?

I have overloaded New, but the constructor is a long routine, and I would
like to make multiple identical copies to display on the form. I think the
code would run much faster if I could clone the object, rather than construct
it multiple times.

My code:

Imports System.Runtime.Serialization.Formatters.Binary
Imports System.Runtime.Serialization
Imports System.IO
<System.Serializable()> _
Public Class ControlGroup
    Inherits Panel

Public Shared Function Clone(ByVal ControlGroup _
       As ControlGroup) As ControlGroup
        Dim MemStream As New MemoryStream(5000)
        Dim BiFormatter As New BinaryFormatter(Nothing, _
            New StreamingContext(StreamingContextStates.Clone))
(this line fails)>>> BiFormatter.Serialize(MemStream, ControlGroup)
        MemStream.Seek(0, SeekOrigin.Begin)
        Dim CG2 As ControlGroup = _
            BiFormatter.Deserialize(MemStream)
        MemStream.Close()
        Return CG2
End Function

The line indicated fails because the ControlGroup object inherits from
Panel, and Panel is not serializable.

The code was adapted from:
http://www.freevbcode.com/ShowCode.asp?ID=5552

17 Apr 2005 12:11 AM

Dennis

You can add a "Clone" method or property to your usercontrol then pass it a
new instance of your control. In the Clone method/property, you can assign
the properties (assuming they are value types) to the new control properties.

Show quoteHide quote

"Charlie" wrote:

> I want to clone an object that is inherited from Panel. I am using
> Serialization, but that is not working because Panel is not Serializable.
>
> I have also tried putting the object into a one member array, then using
> Array.Copy to copy the item to multiple members of a second array, but I
> cannot get that to work either. Each copied member of the new array has the
> same handle as the original object.
>
> Is there an alternate way to clone an object without creating additional
> copies as New?
>
> I have overloaded New, but the constructor is a long routine, and I would
> like to make multiple identical copies to display on the form. I think the
> code would run much faster if I could clone the object, rather than construct
> it multiple times.
>
> My code:
>
> Imports System.Runtime.Serialization.Formatters.Binary
> Imports System.Runtime.Serialization
> Imports System.IO
> <System.Serializable()> _
> Public Class ControlGroup
>     Inherits Panel
>
> Public Shared Function Clone(ByVal ControlGroup _
>        As ControlGroup) As ControlGroup
>         Dim MemStream As New MemoryStream(5000)
>         Dim BiFormatter As New BinaryFormatter(Nothing, _
>             New StreamingContext(StreamingContextStates.Clone))
> (this line fails)>>> BiFormatter.Serialize(MemStream, ControlGroup)
>         MemStream.Seek(0, SeekOrigin.Begin)
>         Dim CG2 As ControlGroup = _
>             BiFormatter.Deserialize(MemStream)
>         MemStream.Close()
>         Return CG2
> End Function
>
> The line indicated fails because the ControlGroup object inherits from
> Panel, and Panel is not serializable.
>
> The code was adapted from:
> http://www.freevbcode.com/ShowCode.asp?ID=5552
>
>
>