How to identify whether visibility of the control is changed by user or not?

问题

My usercontrol inherits System.Windows.Forms.Control class. The following link describes the "Visible" property of control Control.Visible

As per the above link, if control is present in inactive tab, then Control.Visible will return false even though we did not set it programmatically

Question: How do I identify whether visibility was disabled by user or other controls?

Note: I tried overriding the Visible property of Contorl but it's not overridable.

Explanation

If my control is present in unselected tab, then Control.Visible returns false. If the user wants to draw the control (export) in a Bitmap or something else, I need to determine the visibility of child controls too. Since my control is not visible, there is no reliable way available to determine the visibility of child controls

回答1:

All controls in windows forms internally maintain their state. Visibility is also one of the things they maintain in state. Because it helps to identify why visibility of the control was changed.

Control.Visible will return false if there is a control above your control or parent of your control is hidden. But value of Visible property in state will be false only if user set it to false.

Code:

        //Method to ensure the visibility of a control
        public bool DetermineVisibility(Control control)
        {
            //Avoid reflection if control is visible
            if (control.Visible)
                return true;

            //Find non-public GetState method of control using reflection
            System.Reflection.MethodInfo GetStateMethod = control.GetType().GetMethod("GetState", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic);

            //return control's visibility if GetState method not found
            if (GetStateMethod != null)     
                //return visibility from the state maintained for control
                return (bool)(GetStateMethod.Invoke(control, new object[] { 2 }));
            return false;
        }

来源：https://stackoverflow.com/questions/27596529/how-to-identify-whether-visibility-of-the-control-is-changed-by-user-or-not