Question

I have a non-visual component which manages other visual controls.

I need to have a reference to the form that the component is operating on, but i don’t know how to get it.

I am unsure of adding a constructor with the parent specified as control, as i want the component to work by just being dropped into the designer.

The other thought i had was to have a Property of parent as a control, with the default value as ‘Me’

any suggestions would be great

Edit:

To clarify, this is a component, not a control, see here :ComponentModel.Component

Answer 1

[It is important to understand that the ISite technique below only works at design time. Because ContainerControl is public and gets assigned a value VisualStudio will write initialization code that sets it at run-time. Site is set at run-time, but you can’t get ContainerControl from it]

Here’s an article that describes how to do it for a non-visual component.

Basically you need to add a property ContainerControl to your component:

public ContainerControl ContainerControl {   get { return _containerControl; }   set { _containerControl = value; } } private ContainerControl _containerControl = null; 

and override the Site property:

public override ISite Site {   get { return base.Site; }   set   {     base.Site = value;     if (value == null)     {       return;     }      IDesignerHost host = value.GetService(         typeof(IDesignerHost)) as IDesignerHost;     if (host != null)     {         IComponent componentHost = host.RootComponent;         if (componentHost is ContainerControl)         {             ContainerControl = componentHost as ContainerControl;         }     }   } } 

If you do this, the ContainerControl will be initialized to reference the containing form by the designer. The linked article explains it in more detail.

A good way to see how to do things is to look at the implementation of Types in the .NET Framework that have behaviour similar to what you want with a tool such as Lutz Reflector. In this case, System.Windows.Forms.ErrorProvider is a good example to look at: a Component that needs to know its containing Form.