c# - Shown handler in Form's base class in the way of designer -

i have base class inherits form, registers event handler on shown:

class baseclass : form {     public baseclass() : base() {         shown += new eventhandler(baseclass_shown);     }     void baseclass_shown(object sender, eventargs e) {         close();         messagebox.show("this cannot opened.");     } } 

now, when subclass form , open in designer, messsage , closes form in designer making impossible me visually edit it.

is there perhaps boolean can use prevent close() , messagebox happen?

(little background: close not called, depends on runtime settings , data)

some events fired in designer well, gives winforms designer wysiwyg ability. notably paint, shown fired, etcetera. designmode property provided allow tell whether event handler running @ design-time. fix:

void baseclass_shown(object sender, eventargs e) {     if (!this.designmode) {         close();         messagebox.show("this cannot opened.");     } } 

do note flaw in approach, event fires derived form. might helping much.