CODEWITHSUNDEEP
c#winformsuser-controls
JDMX
JDMX

Reputation: 1509

Proper way to override Control.ControlCollection

I went about creating a custom TabControl widget so that I could accurately paint the tab with a close X on the right edge of the tab. I have a custom array class that holds all of the tabs.

So I override the CreateControlsInstance instance class and redefine the Controls class so I can hide it during reflection serialization.

protected override Control.ControlCollection CreateControlsInstance() {
  return new ControlCollection( this );
}

[Browsable( false ), DesignerSerializationVisibility( DesignerSerializationVisibility.Hidden )]
private new Control.ControlCollection Controls {
  get { return base.Controls; }
}

I then create the override class.

public new class ControlCollection: Control.ControlCollection {
  private xTabControl owner;

  public ControlCollection( xTabControl owner ): base( owner ) {
    this.owner = owner;
  }

  public override void Add( Control value ) {
    if ( !(value is xTabPage) )
      throw new Exception( "The control must be of type xTabPage" );

    xTabPage tabPage = (xTabPage)value;

    if ( !owner.inTabEvent )
      owner._tabPages.Add( tabPage );

    base.Add( value );
  }

  public override void Remove( Control value ) {
    if ( !(value is xTabPage) )
      throw new Exception( "The control must be of type JDMX.Widget.xTabPage" );

    if ( !owner.inTabEvent ) {
      xTabPage tabPage = (xTabPage)value;
      owner._tabPages.Remove( tabPage );
    }

    base.Remove( value );
  }

  public override void Clear() {
    owner._tabPages.Clear();
  }
}

Currently this works but if the Controls class can still call methods SetChildIndex, etc which changes the underlying arraylist but not the tabPages array.

I would like to be able to eliminate the need for the new ControlCollection class to have to use the base class for registering the new xTabPage objects with the xTabControl.

I have already been through the class structure with .Net Reflector. I am hoping to not have to copy half of the Control class in order to get the registration of the new widget to work.

I know this is a long shot but has anyone had any success doing this?

Upvotes: 4

Views: 3487

Answers (2)

JDMX
JDMX

Reputation: 1509

Throughout my research on this, I could not find an instance where UserControls could be managed without using System.Windows.Forms.Control.ControlCollection because of the number of functions the assignment of a Control to the Add function provides. It was even worse when I began to incorporate the Designer into the equation. So I have decided to embrace the Controls property using the custom override I gave above. I will now need to keep my private level _tabPages synced with the Control Collection and not the other way around.

Upvotes: 1

caesay
caesay

Reputation: 17233

Well you could use something like .net Reflector (decomplier) to extract the tabcontrol class from .net and edit that class.

Upvotes: 0

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