= Views in HL3 =

== Attributes == 
 * View
 * Content

== Methods to override: == 

{{{#!java
public new Algorithm Content {
get { return (T)base.Content; }
set { base.Content = value; }
}

protected override void OnContentChanged() { 
  base.OnContentChanged();
  if (Content != null) {
    // set controls to Content values
  } else {
    // set default values in controls
  }
}

protected override void RegisterContentEvents() {
 
}

protected override void DeRegisterContentEvents() {
 
}
}}}

Events happen asynchronous --> Invoke required. 

Views must still work if content is NULL. 
{{{#!java
private void Content_XYZChanged(object sender, System.EventArgs e) {
  if (InvokeRequired) {
    Invoke(new EventHandler(Content_ExecutionStateChanged), sender, e);
  } else {
    // set controls 
    SetEnabledStateControls();
  }
}
}}}

=== SetEnabledStateOfControls: ===

In principle all Views have 2 possible states: 
* Locked: 
* ReadOnly: cf. Results --> those can't be changed; this is not configured in the object graph but in the views

* Either via ViewHost or manually 

OnContentChanged --> update content here 
SetEnabledStateOfControls --> only update enabled and readonly here

=== Default Views: ===
 * The most specific default view is used for inherited classes. 


protected override void SetEnabledStateOfControls() {

}

=== NamedItems: ===
You should make sure that if CanChangeName is false --> ReadOnly

private void Content_NameChanged(object sender, EventArgs e) {
  if (InvokeRequired) {
    Invoke(...);
  } else {
    
  }
}

AsynchronosContentView, ItemView --> derive from those, not from ContentView or other views in MainForm.WindowsForm (uses Invoke synchronous --> can get messy). 

Andreas has prepared a useful snippet that you may use to easily create a template for your view. 


== General advice: ==
If you program views that are not sealed --> make everything protected to allow inheritance.