Instantiating new objects with Generics

[Simon Woods]

Hi

I have a factory class which I want to use to create new objects which
inherit a certain base type so I have a declaration

Public Class MyOwnFactory(Of T As MyOwnBase)

As I understand it, a new MyOwnFactory will get instantiated for every
different type of class implementing MyOwnBase. (This is what I want
anyway as the factory is holding a cache of previously created objects
of this type)


In the class, I have some methods :


Public Function GetMyObject(ByV al p_key As String, ByVal p_reload As
Boolean) As T

....

Dim l_def As T = CreateMyObject( l_dto)

...

Return l_def
End Function

Private Function CreateMyObject( ) As T

Dim l_def As T = New T()

If LoadCommonData( l_def, l_data) then

endif

Return l_def

End Function

I'm getting the error

"'New' cannot be used on a type parameter that does not have a 'New'
constraint." against the line

Dim l_def As T = New T()

Because it is a factory, I want to keep the New-ing local to the factory
(so I don't want public constructors on the types inheriting MyOwnBase)
and I wondering if someone could explain a way to do this or perhaps an
alternative way of looking at this.

Thx in advance

Simon

[Bill McCarthy]

Re: Instantiating new objects with Generics

Public Class MyOwnFactory(Of T As {New, MyOwnBase})


"Simon Woods" <simonjwoods@ho tmail.comwrote in message
news:esbziBawIH A.3680@TK2MSFTN GP05.phx.gbl...

Hi
>
I have a factory class which I want to use to create new objects which
inherit a certain base type so I have a declaration
>
Public Class MyOwnFactory(Of T As MyOwnBase)
>
As I understand it, a new MyOwnFactory will get instantiated for every
different type of class implementing MyOwnBase. (This is what I want
anyway as the factory is holding a cache of previously created objects of
this type)
>
>
In the class, I have some methods :
>
>
Public Function GetMyObject(ByV al p_key As String, ByVal p_reload As
Boolean) As T
>
....
>
Dim l_def As T = CreateMyObject( l_dto)
>
...
>
Return l_def
End Function
>
Private Function CreateMyObject( ) As T
>
Dim l_def As T = New T()
>
If LoadCommonData( l_def, l_data) then
>
endif
>
Return l_def
>
End Function
>
I'm getting the error
>
"'New' cannot be used on a type parameter that does not have a 'New'
constraint." against the line
>
Dim l_def As T = New T()
>
Because it is a factory, I want to keep the New-ing local to the factory
(so I don't want public constructors on the types inheriting MyOwnBase)
and I wondering if someone could explain a way to do this or perhaps an
alternative way of looking at this.
>
Thx in advance
>
Simon
>
>
>
>

[Simon Woods]

Re: Instantiating new objects with Generics

Thx Bill

When I introduce the New constraint, an error is generated

"'MyOwnClasses. MyOwnClass' must have a public parameterless instance
constructor to satisfy the 'New' constraint for type parameter 'T'."

where the factory is instantiated with

Dim l_factory As MyOwnClasses.Fa ctory(Of MyOwnClasses.My OwnClass) _
= MyOwnClasses.Fa ctory(Of MyOwnClasses.My OwnClass).Insta nce

(It's a singleton btw)

I'm not too sure how to get round this, as it seems that it is looking
for a public New constructor which I don't want to supply because I want
the factory to be doing all the newing

Thanks again

S


Bill McCarthy wrote:

Public Class MyOwnFactory(Of T As {New, MyOwnBase})
>
>
"Simon Woods" <simonjwoods@ho tmail.comwrote in message
news:esbziBawIH A.3680@TK2MSFTN GP05.phx.gbl...

>Hi
>>
>I have a factory class which I want to use to create new objects which
>inherit a certain base type so I have a declaration
>>
> Public Class MyOwnFactory(Of T As MyOwnBase)
>>
>As I understand it, a new MyOwnFactory will get instantiated for every
>different type of class implementing MyOwnBase. (This is what I want
>anyway as the factory is holding a cache of previously created objects
>of this type)
>>
>>
>In the class, I have some methods :
>>
>>
> Public Function GetMyObject(ByV al p_key As String, ByVal p_reload As
>Boolean) As T
>>
> ....
>>
> Dim l_def As T = CreateMyObject( l_dto)
>>
> ...
>>
> Return l_def
> End Function
>>
> Private Function CreateMyObject( ) As T
>>
> Dim l_def As T = New T()
>>
> If LoadCommonData( l_def, l_data) then
>>
> endif
>>
> Return l_def
>>
> End Function
>>
>I'm getting the error
>>
>"'New' cannot be used on a type parameter that does not have a 'New'
>constraint." against the line
>>
> Dim l_def As T = New T()
>>
>Because it is a factory, I want to keep the New-ing local to the
>factory (so I don't want public constructors on the types inheriting
>MyOwnBase) and I wondering if someone could explain a way to do this
>or perhaps an alternative way of looking at this.
>>
>Thx in advance
>>
>Simon
>>
>>
>>
>>

>

[Bill McCarthy]

Re: Instantiating new objects with Generics

From generic code the only constraint available for creating instances is
New


"Simon Woods" <simonjwoods@ho tmail.comwrote in message
news:u1lPCgawIH A.2188@TK2MSFTN GP04.phx.gbl...

Thx Bill
>
When I introduce the New constraint, an error is generated
>
"'MyOwnClasses. MyOwnClass' must have a public parameterless instance
constructor to satisfy the 'New' constraint for type parameter 'T'."
where the factory is instantiated with
>
Dim l_factory As MyOwnClasses.Fa ctory(Of MyOwnClasses.My OwnClass) _
= MyOwnClasses.Fa ctory(Of MyOwnClasses.My OwnClass).Insta nce
>
(It's a singleton btw)
>
I'm not too sure how to get round this, as it seems that it is looking for
a public New constructor which I don't want to supply because I want the
factory to be doing all the newing
>
Thanks again
>
S
>
>
Bill McCarthy wrote:

>Public Class MyOwnFactory(Of T As {New, MyOwnBase})
>>
>>
>"Simon Woods" <simonjwoods@ho tmail.comwrote in message
>news:esbziBawI HA.3680@TK2MSFT NGP05.phx.gbl.. .

>>Hi
>>>
>>I have a factory class which I want to use to create new objects which
>>inherit a certain base type so I have a declaration
>>>
>> Public Class MyOwnFactory(Of T As MyOwnBase)
>>>
>>As I understand it, a new MyOwnFactory will get instantiated for every
>>different type of class implementing MyOwnBase. (This is what I want
>>anyway as the factory is holding a cache of previously created objects
>>of this type)
>>>
>>>
>>In the class, I have some methods :
>>>
>>>
>> Public Function GetMyObject(ByV al p_key As String, ByVal p_reload As
>>Boolean) As T
>>>
>> ....
>>>
>> Dim l_def As T = CreateMyObject( l_dto)
>>>
>> ...
>>>
>> Return l_def
>> End Function
>>>
>> Private Function CreateMyObject( ) As T
>>>
>> Dim l_def As T = New T()
>>>
>> If LoadCommonData( l_def, l_data) then
>>>
>> endif
>>>
>> Return l_def
>>>
>> End Function
>>>
>>I'm getting the error
>>>
>>"'New' cannot be used on a type parameter that does not have a 'New'
>>constraint. " against the line
>>>
>> Dim l_def As T = New T()
>>>
>>Because it is a factory, I want to keep the New-ing local to the factory
>>(so I don't want public constructors on the types inheriting MyOwnBase)
>>and I wondering if someone could explain a way to do this or perhaps an
>>alternative way of looking at this.
>>>
>>Thx in advance
>>>
>>Simon
>>>
>>>
>>>
>>>

>>

[Simon Woods]

Re: Instantiating new objects with Generics

So is it a case of using Reflection to lookup the type of T and create
an object of that type and return it as a T ... or will I suffer from
the same problem that Reflection also needs a public constructor.

I have been looking at this approach, but have encountered a similar
problem (but this time at runtime presumably because of its latebound
nature) when trying to use the following - ...

Dim l_myOwnClass As T = CType(Activator .CreateInstance (GetType(T), _
'
System.Reflecti on.BindingFlags .NonPublic Or _
'
System.Reflecti on.BindingFlags .Instance), T)



Bill McCarthy wrote:

From generic code the only constraint available for creating instances
is New
>
>
"Simon Woods" <simonjwoods@ho tmail.comwrote in message
news:u1lPCgawIH A.2188@TK2MSFTN GP04.phx.gbl...

>Thx Bill
>>
>When I introduce the New constraint, an error is generated
>>
>"'MyOwnClasses .MyOwnClass' must have a public parameterless instance
>constructor to satisfy the 'New' constraint for type parameter 'T'."
>where the factory is instantiated with
>>
>Dim l_factory As MyOwnClasses.Fa ctory(Of MyOwnClasses.My OwnClass) _
> = MyOwnClasses.Fa ctory(Of MyOwnClasses.My OwnClass).Insta nce
>>
>(It's a singleton btw)
>>
>I'm not too sure how to get round this, as it seems that it is looking
>for a public New constructor which I don't want to supply because I
>want the factory to be doing all the newing
>>
>Thanks again
>>
>S
>>
>>
>Bill McCarthy wrote:

>>Public Class MyOwnFactory(Of T As {New, MyOwnBase})
>>>
>>>
>>"Simon Woods" <simonjwoods@ho tmail.comwrote in message
>>news:esbziBaw IHA.3680@TK2MSF TNGP05.phx.gbl. ..
>>>Hi
>>>>
>>>I have a factory class which I want to use to create new objects
>>>which inherit a certain base type so I have a declaration
>>>>
>>> Public Class MyOwnFactory(Of T As MyOwnBase)
>>>>
>>>As I understand it, a new MyOwnFactory will get instantiated for
>>>every different type of class implementing MyOwnBase. (This is what
>>>I want anyway as the factory is holding a cache of previously
>>>created objects of this type)
>>>>
>>>>
>>>In the class, I have some methods :
>>>>
>>>>
>>> Public Function GetMyObject(ByV al p_key As String, ByVal p_reload
>>>As Boolean) As T
>>>>
>>> ....
>>>>
>>> Dim l_def As T = CreateMyObject( l_dto)
>>>>
>>> ...
>>>>
>>> Return l_def
>>> End Function
>>>>
>>> Private Function CreateMyObject( ) As T
>>>>
>>> Dim l_def As T = New T()
>>>>
>>> If LoadCommonData( l_def, l_data) then
>>>>
>>> endif
>>>>
>>> Return l_def
>>>>
>>> End Function
>>>>
>>>I'm getting the error
>>>>
>>>"'New' cannot be used on a type parameter that does not have a 'New'
>>>constraint ." against the line
>>>>
>>> Dim l_def As T = New T()
>>>>
>>>Because it is a factory, I want to keep the New-ing local to the
>>>factory (so I don't want public constructors on the types inheriting
>>>MyOwnBase) and I wondering if someone could explain a way to do this
>>>or perhaps an alternative way of looking at this.
>>>>
>>>Thx in advance
>>>>
>>>Simon
>>>>
>>>>
>>>>
>>>>
>>>

>

[Bill McCarthy]

Re: Instantiating new objects with Generics

The reflection call should work. You want to include the
System.Reflecti on.BindingFlags .CreateInstance flag


"Simon Woods" <simonjwoods@ho tmail.comwrote in message
news:uao76xawIH A.4488@TK2MSFTN GP04.phx.gbl...

So is it a case of using Reflection to lookup the type of T and create an
object of that type and return it as a T ... or will I suffer from the
same problem that Reflection also needs a public constructor.
>
I have been looking at this approach, but have encountered a similar
problem (but this time at runtime presumably because of its latebound
nature) when trying to use the following - ...
>
Dim l_myOwnClass As T = CType(Activator .CreateInstance (GetType(T), _
' System.Reflecti on.BindingFlags .NonPublic Or _
' System.Reflecti on.BindingFlags .Instance), T)
>
>
>
Bill McCarthy wrote:

> From generic code the only constraint available for creating instances
>is New
>>
>>
>"Simon Woods" <simonjwoods@ho tmail.comwrote in message
>news:u1lPCgawI HA.2188@TK2MSFT NGP04.phx.gbl.. .

>>Thx Bill
>>>
>>When I introduce the New constraint, an error is generated
>>>
>>"'MyOwnClasse s.MyOwnClass' must have a public parameterless instance
>>constructor to satisfy the 'New' constraint for type parameter 'T'."
>>where the factory is instantiated with
>>>
>>Dim l_factory As MyOwnClasses.Fa ctory(Of MyOwnClasses.My OwnClass) _
>> = MyOwnClasses.Fa ctory(Of MyOwnClasses.My OwnClass).Insta nce
>>>
>>(It's a singleton btw)
>>>
>>I'm not too sure how to get round this, as it seems that it is looking
>>for a public New constructor which I don't want to supply because I want
>>the factory to be doing all the newing
>>>
>>Thanks again
>>>
>>S
>>>
>>>
>>Bill McCarthy wrote:
>>>Public Class MyOwnFactory(Of T As {New, MyOwnBase})
>>>>
>>>>
>>>"Simon Woods" <simonjwoods@ho tmail.comwrote in message
>>>news:esbziBa wIHA.3680@TK2MS FTNGP05.phx.gbl ...
>>>>Hi
>>>>>
>>>>I have a factory class which I want to use to create new objects which
>>>>inherit a certain base type so I have a declaration
>>>>>
>>>> Public Class MyOwnFactory(Of T As MyOwnBase)
>>>>>
>>>>As I understand it, a new MyOwnFactory will get instantiated for every
>>>>different type of class implementing MyOwnBase. (This is what I want
>>>>anyway as the factory is holding a cache of previously created objects
>>>>of this type)
>>>>>
>>>>>
>>>>In the class, I have some methods :
>>>>>
>>>>>
>>>> Public Function GetMyObject(ByV al p_key As String, ByVal p_reload As
>>>>Boolean) As T
>>>>>
>>>> ....
>>>>>
>>>> Dim l_def As T = CreateMyObject( l_dto)
>>>>>
>>>> ...
>>>>>
>>>> Return l_def
>>>> End Function
>>>>>
>>>> Private Function CreateMyObject( ) As T
>>>>>
>>>> Dim l_def As T = New T()
>>>>>
>>>> If LoadCommonData( l_def, l_data) then
>>>>>
>>>> endif
>>>>>
>>>> Return l_def
>>>>>
>>>> End Function
>>>>>
>>>>I'm getting the error
>>>>>
>>>>"'New' cannot be used on a type parameter that does not have a 'New'
>>>>constraint. " against the line
>>>>>
>>>> Dim l_def As T = New T()
>>>>>
>>>>Because it is a factory, I want to keep the New-ing local to the
>>>>factory (so I don't want public constructors on the types inheriting
>>>>MyOwnBase ) and I wondering if someone could explain a way to do this
>>>>or perhaps an alternative way of looking at this.
>>>>>
>>>>Thx in advance
>>>>>
>>>>Simon
>>>>>
>>>>>
>>>>>
>>>>>
>>>>

>>

[Simon Woods]

Re: Instantiating new objects with Generics

Ok ... thx very much Bill

So I've tried this cmd with a protected, private and friend constructor
on MyOwnClass

Return CType(Activator .CreateInstance (GetType(T), _
System.Reflecti on.BindingFlags .NonPublic Or
_
System.Reflecti on.BindingFlags .CreateInstance ), T)

but it's erroring with

System.MissingM ethodException: Constructor on type
'MyOwnClasses.M yOwnClass' not found..

Any other suggestions ? I also tried putting an explicit constructor on
MyOwnBase Because MyOwnClass is inheriting it but got the same error

thx again



Bill McCarthy wrote:

The reflection call should work. You want to include the
System.Reflecti on.BindingFlags .CreateInstance flag
>
>
"Simon Woods" <simonjwoods@ho tmail.comwrote in message
news:uao76xawIH A.4488@TK2MSFTN GP04.phx.gbl...

>So is it a case of using Reflection to lookup the type of T and create
>an object of that type and return it as a T ... or will I suffer from
>the same problem that Reflection also needs a public constructor.
>>
>I have been looking at this approach, but have encountered a similar
>problem (but this time at runtime presumably because of its latebound
>nature) when trying to use the following - ...
>>
>Dim l_myOwnClass As T = CType(Activator .CreateInstance (GetType(T), _
> ' System.Reflecti on.BindingFlags .NonPublic Or _
> ' System.Reflecti on.BindingFlags .Instance), T)
>>
>>
>>
>Bill McCarthy wrote:

>> From generic code the only constraint available for creating
>>instances is New
>>>
>>>
>>"Simon Woods" <simonjwoods@ho tmail.comwrote in message
>>news:u1lPCgaw IHA.2188@TK2MSF TNGP04.phx.gbl. ..
>>>Thx Bill
>>>>
>>>When I introduce the New constraint, an error is generated
>>>>
>>>"'MyOwnClass es.MyOwnClass' must have a public parameterless instance
>>>constructo r to satisfy the 'New' constraint for type parameter 'T'."
>>>where the factory is instantiated with
>>>>
>>>Dim l_factory As MyOwnClasses.Fa ctory(Of MyOwnClasses.My OwnClass) _
>>> = MyOwnClasses.Fa ctory(Of MyOwnClasses.My OwnClass).Insta nce
>>>>
>>>(It's a singleton btw)
>>>>
>>>I'm not too sure how to get round this, as it seems that it is
>>>looking for a public New constructor which I don't want to supply
>>>because I want the factory to be doing all the newing
>>>>
>>>Thanks again
>>>>
>>>S
>>>>
>>>>
>>>Bill McCarthy wrote:
>>>>Public Class MyOwnFactory(Of T As {New, MyOwnBase})
>>>>>
>>>>>
>>>>"Simon Woods" <simonjwoods@ho tmail.comwrote in message
>>>>news:esbziB awIHA.3680@TK2M SFTNGP05.phx.gb l...
>>>>>Hi
>>>>>>
>>>>>I have a factory class which I want to use to create new objects
>>>>>which inherit a certain base type so I have a declaration
>>>>>>
>>>>> Public Class MyOwnFactory(Of T As MyOwnBase)
>>>>>>
>>>>>As I understand it, a new MyOwnFactory will get instantiated for
>>>>>every different type of class implementing MyOwnBase. (This is
>>>>>what I want anyway as the factory is holding a cache of previously
>>>>>created objects of this type)
>>>>>>
>>>>>>
>>>>>In the class, I have some methods :
>>>>>>
>>>>>>
>>>>> Public Function GetMyObject(ByV al p_key As String, ByVal
>>>>>p_reload As Boolean) As T
>>>>>>
>>>>> ....
>>>>>>
>>>>> Dim l_def As T = CreateMyObject( l_dto)
>>>>>>
>>>>> ...
>>>>>>
>>>>> Return l_def
>>>>> End Function
>>>>>>
>>>>> Private Function CreateMyObject( ) As T
>>>>>>
>>>>> Dim l_def As T = New T()
>>>>>>
>>>>> If LoadCommonData( l_def, l_data) then
>>>>>>
>>>>> endif
>>>>>>
>>>>> Return l_def
>>>>>>
>>>>> End Function
>>>>>>
>>>>>I'm getting the error
>>>>>>
>>>>>"'New' cannot be used on a type parameter that does not have a
>>>>>'New' constraint." against the line
>>>>>>
>>>>> Dim l_def As T = New T()
>>>>>>
>>>>>Because it is a factory, I want to keep the New-ing local to the
>>>>>factory (so I don't want public constructors on the types
>>>>>inheriti ng MyOwnBase) and I wondering if someone could explain a
>>>>>way to do this or perhaps an alternative way of looking at this.
>>>>>>
>>>>>Thx in advance
>>>>>>
>>>>>Simon
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>

>

[Simon Woods]

Re: Instantiating new objects with Generics

Simon Woods wrote:

Ok ... thx very much Bill

Actually Bill, ... I'm not going with the Reflection approach because it
seems noticably slower even to report an error compare to the New T()
approach ... so I'll have a rethink about how to re-engineer this so I
get all early binding.

thx very much again...

Simon

[Bill McCarthy]

Re: Instantiating new objects with Generics

Right as it should. There is no overload that matches that .

CType(Activator .CreateInstance (GetType(T), CreateInstance Or [Public] Or
Instance, Nothing, Nothing, Nothing), T)


"Simon Woods" <simonjwoods@ho tmail.comwrote in message
news:e%23vgyEbw IHA.4376@TK2MSF TNGP06.phx.gbl. ..

Ok ... thx very much Bill
>
So I've tried this cmd with a protected, private and friend constructor on
MyOwnClass
>
Return CType(Activator .CreateInstance (GetType(T), _
System.Reflecti on.BindingFlags .NonPublic Or _
System.Reflecti on.BindingFlags .CreateInstance ), T)
>
but it's erroring with
>
System.MissingM ethodException: Constructor on type
'MyOwnClasses.M yOwnClass' not found..
Any other suggestions ? I also tried putting an explicit constructor on
MyOwnBase Because MyOwnClass is inheriting it but got the same error
>
thx again
>
>
>
Bill McCarthy wrote:

>The reflection call should work. You want to include the
>System.Reflect ion.BindingFlag s.CreateInstanc e flag
>>
>>
>"Simon Woods" <simonjwoods@ho tmail.comwrote in message
>news:uao76xawI HA.4488@TK2MSFT NGP04.phx.gbl.. .

>>So is it a case of using Reflection to lookup the type of T and create
>>an object of that type and return it as a T ... or will I suffer from
>>the same problem that Reflection also needs a public constructor.
>>>
>>I have been looking at this approach, but have encountered a similar
>>problem (but this time at runtime presumably because of its latebound
>>nature) when trying to use the following - ...
>>>
>>Dim l_myOwnClass As T = CType(Activator .CreateInstance (GetType(T), _
>> ' System.Reflecti on.BindingFlags .NonPublic Or _
>> ' System.Reflecti on.BindingFlags .Instance), T)
>>>
>>>
>>>
>>Bill McCarthy wrote:
>>> From generic code the only constraint available for creating instances
>>>is New
>>>>
>>>>
>>>"Simon Woods" <simonjwoods@ho tmail.comwrote in message
>>>news:u1lPCga wIHA.2188@TK2MS FTNGP04.phx.gbl ...
>>>>Thx Bill
>>>>>
>>>>When I introduce the New constraint, an error is generated
>>>>>
>>>>"'MyOwnClas ses.MyOwnClass' must have a public parameterless instance
>>>>construct or to satisfy the 'New' constraint for type parameter 'T'."
>>>>where the factory is instantiated with
>>>>>
>>>>Dim l_factory As MyOwnClasses.Fa ctory(Of MyOwnClasses.My OwnClass) _
>>>> = MyOwnClasses.Fa ctory(Of MyOwnClasses.My OwnClass).Insta nce
>>>>>
>>>>(It's a singleton btw)
>>>>>
>>>>I'm not too sure how to get round this, as it seems that it is looking
>>>>for a public New constructor which I don't want to supply because I
>>>>want the factory to be doing all the newing
>>>>>
>>>>Thanks again
>>>>>
>>>>S
>>>>>
>>>>>
>>>>Bill McCarthy wrote:
>>>>>Public Class MyOwnFactory(Of T As {New, MyOwnBase})
>>>>>>
>>>>>>
>>>>>"Simon Woods" <simonjwoods@ho tmail.comwrote in message
>>>>>news:esbzi BawIHA.3680@TK2 MSFTNGP05.phx.g bl...
>>>>>>Hi
>>>>>>>
>>>>>>I have a factory class which I want to use to create new objects
>>>>>>which inherit a certain base type so I have a declaration
>>>>>>>
>>>>>> Public Class MyOwnFactory(Of T As MyOwnBase)
>>>>>>>
>>>>>>As I understand it, a new MyOwnFactory will get instantiated for
>>>>>>every different type of class implementing MyOwnBase. (This is what
>>>>>>I want anyway as the factory is holding a cache of previously
>>>>>>created objects of this type)
>>>>>>>
>>>>>>>
>>>>>>In the class, I have some methods :
>>>>>>>
>>>>>>>
>>>>>> Public Function GetMyObject(ByV al p_key As String, ByVal p_reload
>>>>>>As Boolean) As T
>>>>>>>
>>>>>> ....
>>>>>>>
>>>>>> Dim l_def As T = CreateMyObject( l_dto)
>>>>>>>
>>>>>> ...
>>>>>>>
>>>>>> Return l_def
>>>>>> End Function
>>>>>>>
>>>>>> Private Function CreateMyObject( ) As T
>>>>>>>
>>>>>> Dim l_def As T = New T()
>>>>>>>
>>>>>> If LoadCommonData( l_def, l_data) then
>>>>>>>
>>>>>> endif
>>>>>>>
>>>>>> Return l_def
>>>>>>>
>>>>>> End Function
>>>>>>>
>>>>>>I'm getting the error
>>>>>>>
>>>>>>"'New' cannot be used on a type parameter that does not have a 'New'
>>>>>>constrain t." against the line
>>>>>>>
>>>>>> Dim l_def As T = New T()
>>>>>>>
>>>>>>Because it is a factory, I want to keep the New-ing local to the
>>>>>>factory (so I don't want public constructors on the types inheriting
>>>>>>MyOwnBase ) and I wondering if someone could explain a way to do this
>>>>>>or perhaps an alternative way of looking at this.
>>>>>>>
>>>>>>Thx in advance
>>>>>>>
>>>>>>Simon
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>

>>

[Simon Woods]

Re: Instantiating new objects with Generics

Bill McCarthy wrote:

Right as it should. There is no overload that matches that .
>
CType(Activator .CreateInstance (GetType(T), CreateInstance Or [Public] Or
Instance, Nothing, Nothing, Nothing), T)

That did it ... thx (I was in a vb6 mode thinking the params were optional!)