Passing Objects as type System.Object

Stephen Travis

I'm trying to ReDim a child object after passing the parent object as System.Object and it throws a System.InvalidC astException:
Cast from type 'Object()' to type 'ChildType()' is not valid. If I pass the parent object as its type, the ReDim succeeds. How can I
ReDim a child object from a parent object passed as System.Object?

Here's the problem...

Private Sub Page_Load
Dim NewParent As New ParentType
addTwoChildrenS ucceeds(NewPare nt)
addTwoChildrenF ails(NewParent)
End Sub

Public Sub addTwoChildrenF ails(ByVal parentobject As System.Object)
ReDim parentobject.Ch ild(1) ' Throws the exception.
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Public Sub addTwoChildrenS ucceeds(ByVal parentobject As ParentType)
ReDim parentobject.Ch ild(1)
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Public Class ParentType
Public ParentName As System.String
Public Child() As ChildType
End Class

Public Class ChildType
Public ChildName As System.String
End Class

Nov 20 '05 #1

Subscribe Reply

1305

The Grim Reaper

You're nearly there...

Public Sub addTwoChildrenF ails(ByVal parentobject As System.Object)
parentobject = DirectCast(pare ntobject, ParentType)
ReDim parentobject.Ch ild(1) ' Doesn't throw an exception any
more
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Untested... I'm sure someone else will contradict me.... tis the way of it
:D
_______________ ______________
The Grim Reaper

"Stephen Travis" <st*****@iname. com> wrote in message
news:%2******** ********@TK2MSF TNGP12.phx.gbl. ..

I'm trying to ReDim a child object after passing the parent object as System.Object and it throws a System.InvalidC astException: Cast from type 'Object()' to type 'ChildType()' is not valid. If I pass the parent object as its type, the ReDim succeeds. How can I ReDim a child object from a parent object passed as System.Object?

Here's the problem...

Private Sub Page_Load
Dim NewParent As New ParentType
addTwoChildrenS ucceeds(NewPare nt)
addTwoChildrenF ails(NewParent)
End Sub

Public Sub addTwoChildrenF ails(ByVal parentobject As System.Object)
ReDim parentobject.Ch ild(1) ' Throws the exception.
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Public Sub addTwoChildrenS ucceeds(ByVal parentobject As ParentType)
ReDim parentobject.Ch ild(1)
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Public Class ParentType
Public ParentName As System.String
Public Child() As ChildType
End Class

Public Class ChildType
Public ChildName As System.String
End Class

Nov 20 '05 #2

Tom Spink

Hi, May I ask why you pass it as an object... will you have different
classes being ReDim'med?

--
HTH,
-- Tom Spink, Über Geek

Woe be the day VBC.EXE says, "OrElse what?"

Please respond to the newsgroup,
so all can benefit
"Stephen Travis" <st*****@iname. com> wrote in message
news:#D******** ******@TK2MSFTN GP12.phx.gbl...

I'm trying to ReDim a child object after passing the parent object as System.Object and it throws a System.InvalidC astException: Cast from type 'Object()' to type 'ChildType()' is not valid. If I pass the parent object as its type, the ReDim succeeds. How can I ReDim a child object from a parent object passed as System.Object?

Here's the problem...

Private Sub Page_Load
Dim NewParent As New ParentType
addTwoChildrenS ucceeds(NewPare nt)
addTwoChildrenF ails(NewParent)
End Sub

Public Sub addTwoChildrenF ails(ByVal parentobject As System.Object)
ReDim parentobject.Ch ild(1) ' Throws the exception.
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Public Sub addTwoChildrenS ucceeds(ByVal parentobject As ParentType)
ReDim parentobject.Ch ild(1)
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Public Class ParentType
Public ParentName As System.String
Public Child() As ChildType
End Class

Public Class ChildType
Public ChildName As System.String
End Class

Nov 20 '05 #3

Stephen Travis

Hi Tom, I'm developing a front-end for a c/s web application that has to support several versions of an XML dialect. For example, my
application has to support two versions of the WMS XML dialect, version 1.3.0 and 1.1.1. One version might have a property that the
other doesn't but otherwise are identical.

So, I create an object of the correct version and pass it to the function as System.Object, which then populates the object
according to it's type and returns it to the caller. Otherwise, I would have to have separate functions to populate every XML
version.

"Tom Spink" <thomasdotspink atsp@mntlworldd otcom> wrote in message news:Ol******** ******@TK2MSFTN GP09.phx.gbl...

Hi, May I ask why you pass it as an object... will you have different
classes being ReDim'med?

--
HTH,
-- Tom Spink, Über Geek

Woe be the day VBC.EXE says, "OrElse what?"

Please respond to the newsgroup,
so all can benefit
"Stephen Travis" <st*****@iname. com> wrote in message
news:#D******** ******@TK2MSFTN GP12.phx.gbl...
I'm trying to ReDim a child object after passing the parent object as

System.Object and it throws a System.InvalidC astException:
Cast from type 'Object()' to type 'ChildType()' is not valid. If I pass

the parent object as its type, the ReDim succeeds. How can I
ReDim a child object from a parent object passed as System.Object?

Here's the problem...

Private Sub Page_Load
Dim NewParent As New ParentType
addTwoChildrenS ucceeds(NewPare nt)
addTwoChildrenF ails(NewParent)
End Sub

Public Sub addTwoChildrenF ails(ByVal parentobject As System.Object)
ReDim parentobject.Ch ild(1) ' Throws the exception.
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Public Sub addTwoChildrenS ucceeds(ByVal parentobject As ParentType)
ReDim parentobject.Ch ild(1)
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Public Class ParentType
Public ParentName As System.String
Public Child() As ChildType
End Class

Public Class ChildType
Public ChildName As System.String
End Class

Nov 20 '05 #4

Stephen Travis

That throws the same error but this approach works;

Public Sub addTwoChildrenF ails(ByVal parentobject1 As System.Object)
Dim parentobject As New ParentType
parentobject = parentobject1
ReDim parentobject.Ch ild(1) ' Doesn't throw an exception any more
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

However, I need to make the Type a variable. For example;

Public Sub addTwoChildrenF ails(ByVal parentobject1 As System.Object)
If parentobject1.G etType Is GetType(ParentT ype) Then Dim parentobject As New ParentType
parentobject = parentobject1
ReDim parentobject.Ch ild(1) ' Doesn't throw an exception any more
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

This creates a scope problem. Your original approach avoids this problem. Any ideas?

"The Grim Reaper" <gr*********@bt openworld.com> wrote in message news:cc******** **@hercules.bti nternet.com...

You're nearly there...

Public Sub addTwoChildrenF ails(ByVal parentobject As System.Object)
parentobject = DirectCast(pare ntobject, ParentType)
ReDim parentobject.Ch ild(1) ' Doesn't throw an exception any
more
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Untested... I'm sure someone else will contradict me.... tis the way of it
:D
_______________ ______________
The Grim Reaper

"Stephen Travis" <st*****@iname. com> wrote in message
news:%2******** ********@TK2MSF TNGP12.phx.gbl. ..
I'm trying to ReDim a child object after passing the parent object as

System.Object and it throws a System.InvalidC astException:
Cast from type 'Object()' to type 'ChildType()' is not valid. If I pass

the parent object as its type, the ReDim succeeds. How can I
ReDim a child object from a parent object passed as System.Object?

Here's the problem...

Private Sub Page_Load
Dim NewParent As New ParentType
addTwoChildrenS ucceeds(NewPare nt)
addTwoChildrenF ails(NewParent)
End Sub

Public Sub addTwoChildrenF ails(ByVal parentobject As System.Object)
ReDim parentobject.Ch ild(1) ' Throws the exception.
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Public Sub addTwoChildrenS ucceeds(ByVal parentobject As ParentType)
ReDim parentobject.Ch ild(1)
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Public Class ParentType
Public ParentName As System.String
Public Child() As ChildType
End Class

Public Class ChildType
Public ChildName As System.String
End Class

Nov 20 '05 #5

Stephen Travis

Public Sub addTwoChildren( ByRef parentobject As System.Object)
If parentobject.Ge tType Is GetType(ParentT ype) Then
ReDim DirectCast(pare ntobject, ParentType).Chi ld(1)
End If
parentobject.Pa rentName = "Susan"
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Although it would be better if I could DirectCast the whole object 8-)

Thanks for the help.

"The Grim Reaper" <gr*********@bt openworld.com> wrote in message news:cc******** **@hercules.bti nternet.com...

You're nearly there...

Public Sub addTwoChildrenF ails(ByVal parentobject As System.Object)
parentobject = DirectCast(pare ntobject, ParentType)
ReDim parentobject.Ch ild(1) ' Doesn't throw an exception any
more
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Untested... I'm sure someone else will contradict me.... tis the way of it
:D
_______________ ______________
The Grim Reaper

"Stephen Travis" <st*****@iname. com> wrote in message
news:%2******** ********@TK2MSF TNGP12.phx.gbl. ..
I'm trying to ReDim a child object after passing the parent object as

System.Object and it throws a System.InvalidC astException:
Cast from type 'Object()' to type 'ChildType()' is not valid. If I pass

the parent object as its type, the ReDim succeeds. How can I
ReDim a child object from a parent object passed as System.Object?

Here's the problem...

Private Sub Page_Load
Dim NewParent As New ParentType
addTwoChildrenS ucceeds(NewPare nt)
addTwoChildrenF ails(NewParent)
End Sub

Public Sub addTwoChildrenF ails(ByVal parentobject As System.Object)
ReDim parentobject.Ch ild(1) ' Throws the exception.
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Public Sub addTwoChildrenS ucceeds(ByVal parentobject As ParentType)
ReDim parentobject.Ch ild(1)
parentobject.Ch ild(0) = New ChildType
parentobject.Ch ild(0).ChildNam e = "Brian"
parentobject.Ch ild(1) = New ChildType
parentobject.Ch ild(1).ChildNam e = "Gail"
End Sub

Public Class ParentType
Public ParentName As System.String
Public Child() As ChildType
End Class

Public Class ChildType
Public ChildName As System.String
End Class

Nov 20 '05 #6

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