Constructors in Singleton Class

[Paul Bromley]

Forgive my ignorance on this one as I am trying to use a Singleton class. I
need to use this to have one instance of my Class running and I think I
understand how to do this. My question however is can a singleton class have
a number of paramterised constructors enabling me to pass in parameters or
not?

I am trying to use the following to send in a parmeter to a constructor, but
getting an error with it. I have a feeling that I am not able to do this. Is
there any other way that I can do this.

Dim sPatName As String = "Green"
Dim EMP As CEmPacc = CEmPacc.Create( sPatName)

Class myApp.CEmPacc cannot be indexed because it has no default property

Many thanks

Paul Bromley

[Paul Bromley]

As usual, posting a question has made me think about a possible answer. I am
getting around the problem that I had below by accesing a property in my
class and passing in parameters that are then used in my property. I assume
that this is permissible? I know that this is a stupid question, but I also
assume that I can have a number of properties in my singleton class as I
would any other class - I have only seen very basic examples of Singleton
classes.

Thanks

Paul Bromley
"Paul Bromley" <fl*******@dsl. pipex.com> wrote in message
news:uB******** ******@TK2MSFTN GP10.phx.gbl...

Forgive my ignorance on this one as I am trying to use a Singleton class. I need to use this to have one instance of my Class running and I think I
understand how to do this. My question however is can a singleton class have a number of paramterised constructors enabling me to pass in parameters or
not?

I am trying to use the following to send in a parmeter to a constructor, but getting an error with it. I have a feeling that I am not able to do this. Is there any other way that I can do this.

Dim sPatName As String = "Green"
Dim EMP As CEmPacc = CEmPacc.Create( sPatName)

Class myApp.CEmPacc cannot be indexed because it has no default property

Many thanks

Paul Bromley

[Mike McIntyre [MVP]]

Paul,

You can add properties to a singleton class just as you would to a regular
class.

--
Mike

Mike McIntyre
Visual Basic MVP
www.getdotnetcode.com
"Paul Bromley" <fl*******@dsl. pipex.com> wrote in message
news:e6******** ******@TK2MSFTN GP14.phx.gbl...

As usual, posting a question has made me think about a possible answer. I
am
getting around the problem that I had below by accesing a property in my
class and passing in parameters that are then used in my property. I
assume
that this is permissible? I know that this is a stupid question, but I
also
assume that I can have a number of properties in my singleton class as I
would any other class - I have only seen very basic examples of Singleton
classes.

Thanks

Paul Bromley
"Paul Bromley" <fl*******@dsl. pipex.com> wrote in message
news:uB******** ******@TK2MSFTN GP10.phx.gbl...

Forgive my ignorance on this one as I am trying to use a Singleton class.

I

need to use this to have one instance of my Class running and I think I
understand how to do this. My question however is can a singleton class

have

a number of paramterised constructors enabling me to pass in parameters
or
not?

I am trying to use the following to send in a parmeter to a constructor,

but

getting an error with it. I have a feeling that I am not able to do this.

Is

there any other way that I can do this.

Dim sPatName As String = "Green"
Dim EMP As CEmPacc = CEmPacc.Create( sPatName)

Class myApp.CEmPacc cannot be indexed because it has no default property

Many thanks

Paul Bromley

[Paul Bromley]

Thanks Mike.

Paul
"Mike McIntyre [MVP]" <mi****@getdotn etcode.com> wrote in message
news:On******** ******@TK2MSFTN GP15.phx.gbl...

Paul,

You can add properties to a singleton class just as you would to a regular
class.

--
Mike

Mike McIntyre
Visual Basic MVP
www.getdotnetcode.com
"Paul Bromley" <fl*******@dsl. pipex.com> wrote in message
news:e6******** ******@TK2MSFTN GP14.phx.gbl...

As usual, posting a question has made me think about a possible answer. I am
getting around the problem that I had below by accesing a property in my
class and passing in parameters that are then used in my property. I
assume
that this is permissible? I know that this is a stupid question, but I
also
assume that I can have a number of properties in my singleton class as I
would any other class - I have only seen very basic examples of Singleton classes.

Thanks

Paul Bromley
"Paul Bromley" <fl*******@dsl. pipex.com> wrote in message
news:uB******** ******@TK2MSFTN GP10.phx.gbl...

Forgive my ignorance on this one as I am trying to use a Singleton class.

I

need to use this to have one instance of my Class running and I think I
understand how to do this. My question however is can a singleton class

have

a number of paramterised constructors enabling me to pass in parameters
or
not?

I am trying to use the following to send in a parmeter to a

constructor, but

getting an error with it. I have a feeling that I am not able to do

this. Is

there any other way that I can do this.

Dim sPatName As String = "Green"
Dim EMP As CEmPacc = CEmPacc.Create( sPatName)

Class myApp.CEmPacc cannot be indexed because it has no default

property
Many thanks

Paul Bromley

[Scott M.]

The message you are getting is indicating that you are trying to pass an
argument where one is not expected. What is the "Create" method you have
there?
"Paul Bromley" <fl*******@dsl. pipex.com> wrote in message
news:uB******** ******@TK2MSFTN GP10.phx.gbl...

Forgive my ignorance on this one as I am trying to use a Singleton class.
I
need to use this to have one instance of my Class running and I think I
understand how to do this. My question however is can a singleton class
have
a number of paramterised constructors enabling me to pass in parameters or
not?

I am trying to use the following to send in a parmeter to a constructor,
but
getting an error with it. I have a feeling that I am not able to do this.
Is
there any other way that I can do this.

Dim sPatName As String = "Green"
Dim EMP As CEmPacc = CEmPacc.Create( sPatName)

Class myApp.CEmPacc cannot be indexed because it has no default property

Many thanks

Paul Bromley

[Scott M.]

Singletons work just as any other class with the exception that you can't
inherit from them.

"Paul Bromley" <fl*******@dsl. pipex.com> wrote in message
news:O4******** *****@TK2MSFTNG P14.phx.gbl...

Thanks Mike.

Paul
"Mike McIntyre [MVP]" <mi****@getdotn etcode.com> wrote in message
news:On******** ******@TK2MSFTN GP15.phx.gbl...

Paul,

You can add properties to a singleton class just as you would to a
regular
class.

--
Mike

Mike McIntyre
Visual Basic MVP
www.getdotnetcode.com
"Paul Bromley" <fl*******@dsl. pipex.com> wrote in message
news:e6******** ******@TK2MSFTN GP14.phx.gbl...

> As usual, posting a question has made me think about a possible answer. I > am
> getting around the problem that I had below by accesing a property in
> my
> class and passing in parameters that are then used in my property. I
> assume
> that this is permissible? I know that this is a stupid question, but I
> also
> assume that I can have a number of properties in my singleton class as
> I
> would any other class - I have only seen very basic examples of Singleton > classes.
>
> Thanks
>
> Paul Bromley
>
>
> "Paul Bromley" <fl*******@dsl. pipex.com> wrote in message
> news:uB******** ******@TK2MSFTN GP10.phx.gbl...
>> Forgive my ignorance on this one as I am trying to use a Singleton class. > I
>> need to use this to have one instance of my Class running and I think
>> I
>> understand how to do this. My question however is can a singleton
>> class
> have
>> a number of paramterised constructors enabling me to pass in
>> parameters
>> or
>> not?
>>
>> I am trying to use the following to send in a parmeter to a constructor, > but
>> getting an error with it. I have a feeling that I am not able to do this. > Is
>> there any other way that I can do this.
>>
>> Dim sPatName As String = "Green"
>> Dim EMP As CEmPacc = CEmPacc.Create( sPatName)
>>
>> Class myApp.CEmPacc cannot be indexed because it has no default property >>
>> Many thanks
>>
>> Paul Bromley
>>
>>
>
>

[Herfried K. Wagner [MVP]]

Paul,

"Paul Bromley" <fl*******@dsl. pipex.com> schrieb:

Forgive my ignorance on this one as I am trying to use a Singleton class.
I
need to use this to have one instance of my Class running and I think I
understand how to do this. My question however is can a singleton class
have
a number of paramterised constructors enabling me to pass in parameters or
not?

Quick and dirty:

\\\
Public Class Singleton
Private m_UserName As String
Private m_Password As String

Private m_DefInstance As Singleton

Private Sub New()
'
End Sub

Private Sub New( _
ByVal UserName As String, _
ByVal Password As String _
)
m_UserName = UserName
m_Password = Password
End Sub

Public Function CreateInstance( ) As Singleton
If m_DefInstance Is Nothing Then
m_DefInstance = New Singleton
End If
Return m_DefInstance
End Function

Public Function CreateInstance( _
ByVal UserName As String, _
ByVal Password As String _
) As Singleton
If m_DefInstance Is Nothing Then
m_DefInstance = New Singleton(UserN ame, Password)
End If
Return m_DefInstance
End Function
End Class
///

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

[Herfried K. Wagner [MVP]]

Errata:

Public Class Singleton

=> 'Public NotInheritable Class Singleton'.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

[Paul Bromley]

Many thanks Herfried, Scott & Mike,

I see exactly where I am going wrong now especially from the example that
Herfried has given - I was foolishly trying to send parameters to a Private
Sub New(), and I see quite obviously now that I need to send these to a
Public Function CreateInstance( ) As Singleton instead. I had not seen any
examples of using this type of class with parameters. Another stupid
question - I assume that I can place other initialisation code in this
function - i.e. calls to other Sub routines etc?

Again many thanks - as always I have learnt a lot - will try this later -
off to work now.

Best wishes

Paul Bromley


"Scott M." <s-***@nospam.nosp am> wrote in message
news:Og******** ******@tk2msftn gp13.phx.gbl...

The message you are getting is indicating that you are trying to pass an
argument where one is not expected. What is the "Create" method you have
there?
"Paul Bromley" <fl*******@dsl. pipex.com> wrote in message
news:uB******** ******@TK2MSFTN GP10.phx.gbl...

Forgive my ignorance on this one as I am trying to use a Singleton class. I
need to use this to have one instance of my Class running and I think I
understand how to do this. My question however is can a singleton class
have
a number of paramterised constructors enabling me to pass in parameters or not?

I am trying to use the following to send in a parmeter to a constructor,
but
getting an error with it. I have a feeling that I am not able to do this. Is
there any other way that I can do this.

Dim sPatName As String = "Green"
Dim EMP As CEmPacc = CEmPacc.Create( sPatName)

Class myApp.CEmPacc cannot be indexed because it has no default property

Many thanks

Paul Bromley

[Herfried K. Wagner [MVP]]

Paul,

"Paul Bromley" <fl*******@dsl. pipex.com> schrieb:

I see exactly where I am going wrong now especially from the example that
Herfried has given - I was foolishly trying to send parameters to a
Private
Sub New(), and I see quite obviously now that I need to send these to a
Public Function CreateInstance( ) As Singleton instead. I had not seen any
examples of using this type of class with parameters. Another stupid
question - I assume that I can place other initialisation code in this
function - i.e. calls to other Sub routines etc?

Yes, you can do that.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>