I have to figure out how all this works (what a learning project for the weekend!).
Also, just have to say I get a kick out of your handle and email address. I use
(e-mail address removed) and I thought mine was good<grin>.
Thanks - Jack
| JackRazz, I forgot to add one thing. Put this into the Adding Event, or
| else the user won't be able to add other controls.
|
| Private Sub MyComponentDesigner_ComponentAdding(ByVal sender As
| Object, ByVal e As ComponentEventArgs)
|
| '-- Use your class name here.
| If TypeOf e.Component Is YourClassNameHere Then
| Throw New Exception("Only one instance of this component is
| allowed.")
| End If
|
| End Sub
|
|
| The designer only works at design time so a user may try to add another
| control at run time. To prevent this, you need to add a Shared variable
| to your class so you can error out if they try to add another instance.
| See example:
|
| Class YourClass
|
| Shared inUse as Boolean = False
|
|
| Public Sub New()
| MyBase.New()
|
| '-- If inUse then no more of this componet may be added
| If inUse Then
| Throw (New Exception("Only one instance of this componet
| may be run."))
| End If
|
| '-- Set inUse to True
| inUse = True
|
| 'This call is required by the Component Designer.
| InitializeComponent()
|
| 'Add any initialization after the InitializeComponent() call
|
| End Sub
|
| '--- Make sure you set inuse to Flase when disposing
| Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
| If disposing Then
|
| '-- No longer in use, set to false
| inUse = False
| If Not (components Is Nothing) Then
| components.Dispose()
| End If
| End If
| MyBase.Dispose(disposing)
| End Sub
|
|
|
|
| End class
|
|
|
| > Very interesting, The component services is an area I don't know a thing about.
I'm
| > going to look at it and see if I can get it to work.
| >
| > I appreciate this code snippet - JackRazz
| >
| >
| > | > | Try this: Create a new class as shown below. Then add an designer
| > | attribute to your component class (see below the MyComponentDesigner class).
| > |
| > | Public Class MyComponentDesigner
| > | Inherits ComponentDesigner
| > |
| > | Private CCService As IComponentChangeService
| > |
| > | Public Overrides Sub Initialize(ByVal component As
| > | System.ComponentModel.IComponent)
| > | MyBase.Initialize(component)
| > |
| > | CCService =
| > | DirectCast(MyBase.GetService(GetType(IComponentChangeService)),
| > | IComponentChangeService)
| > |
| > |
| > | AddHandler CCService.ComponentAdding, AddressOf
| > | MyComponentDesigner_ComponentAdding
| > | End Sub
| > |
| > |
| > |
| > | Private Sub MyComponentDesigner_ComponentAdding(ByVal sender As
| > | Object, ByVal e As ComponentEventArgs)
| > | 'code here
| > | Throw New Exception("Only one instance of this component is
| > | allowed")
| > | End Sub
| > |
| > |
| > |
| > | Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
| > |
| > | RemoveHandler CCService.ComponentAdding, AddressOf
| > | MyComponentDesigner_ComponentAdding
| > | MyBase.Dispose(disposing)
| > | End Sub
| > |
| > | End Class
| > |
| > |
| > |
| > | Then put this in your component class:
| > |
| > | <Designer(GetType(MyComponentDesigner))> _
| > | Public Class YourComponent
| > | Inherits System.ComponentModel.Component
| > |
| > | '-- Your code here
| > |
| > |
| > | End Class
| > |
| > |
| > |
| > | > Hi,
| > | > I looked at this issue.. There may be no straight forward way to do this
| > | > at desgin time. But one alternative I can think of is, you can create a
| > | > class library and then basically create a singleton design pattern such
| > | > that only one instance of your class exists in the program. If you want to
| > | > take singleton pattern approach, then do let me know, i can send a sample
| > | > to you.
| > | > Thanks
| > | > Anand Balasubramanian
| > | > Microsoft, Visual Basic .NET
| > | >
| > | > This posting is provided "AS IS" with no warranties, and confers no rights.
| > | > Please reply to newsgroups only. Thanks
| > | >
| >
| >
