Labview如何快速入门

 您重写了该方法，但是您没有在处理程序中调用base.OnLeave(e) ，因此永远不会触发事件。 
 
 文档非常清楚： 
 
 
 
 对继承者的说明： 
 在派生类中重写OnLeave时，请务必调用基类的OnLeave方法，以便已注册的委托接收事件。 
 
 
 所以你需要覆盖这样的方法 
 
protected override void OnLeave(EventArgs e)
{
    base.OnLeave(e);

    Text = CultureInfo.CurrentCulture.TextInfo.ToTitleCase(Text.ToLower());
}
 
 这将导致重写的OnLeave方法和连接到Leave任何可能事件被调用。 

You are overriding the method, but you are not calling base.OnLeave(e) in your handler so the events are never triggered.
 
The documentation is quite clear about this:
 
 
 
Notes to Inheritors:
 When overriding OnLeave in a derived class, be sure to call the base class's OnLeave method so that registered delegates receive the event.
 
 
So you need to override the method like this
 
protected override void OnLeave(EventArgs e)
{
    base.OnLeave(e);

    Text = CultureInfo.CurrentCulture.TextInfo.ToTitleCase(Text.ToLower());
}
 
This will cause both your overridden OnLeave method and any possible events connected to Leave get called.