c# - Constrain a control's Parent to a particular type in Windows Forms with .NET -

i want write control can have parent of type form (or derivatives).

i guess might liken behaviour tabcontrol, or tabpage, tabcontrol cannot have children not of type tabpage, , tabpage cannot have parent not tabcontrol.

however implementation differs because unlike tabcontrol, want form accept type of control, control should ever have parent of type form.

here have tried:

public class customcontrol : containercontrol {     protected override void onparentchanged(eventargs e)     {         base.onparentchanged(e);         if (!(this.parent form))         {             this.parent.controls.remove(this);             throw new argumentexception("customcontrol can child of form");         }     } } 

this causes undesired effects in forms designer, such as:

1. throws exception when trying load form in designer.
2. throws exception when removing control form.
3. the control not resize properly.

i'd appreciate recommendation on how fix this, or points going wrong.

as quite said, simplest answers best...adding additional check if statement fixes everything! - silly me! should have tried sooner!

public class customcontrol : containercontrol {     protected override void onparentchanged(eventargs e)     {         base.onparentchanged(e);         if (this.parent != null && !(this.parent form))         {             this.parent.controls.remove(this);             throw new argumentexception("customcontrol can child of form");         }     } }