XPropertyDescriptor.cs

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using System;
using System.ComponentModel;
using System.Xml.Linq;
 
namespace MS.Internal.Xml.Linq.ComponentModel;
 
internal abstract class XPropertyDescriptor<T, TProperty> : PropertyDescriptor where T : XObject
{
    public override Type ComponentType => typeof(T);
 
    public override bool IsReadOnly => true;
 
    public override Type PropertyType => typeof(TProperty);
 
    public override bool SupportsChangeEvents => true;
 
    public XPropertyDescriptor(string name)
        : base(name, null)
    {
    }
 
    public override void AddValueChanged(object component, EventHandler handler)
    {
        bool flag = GetValueChangedHandler(component) != null;
        base.AddValueChanged(component, handler);
        if (!flag && component is T val && GetValueChangedHandler(component) != null)
        {
            val.Changing += OnChanging;
            val.Changed += OnChanged;
        }
    }
 
    public override bool CanResetValue(object component)
    {
        return false;
    }
 
    public override void RemoveValueChanged(object component, EventHandler handler)
    {
        base.RemoveValueChanged(component, handler);
        if (component is T val && GetValueChangedHandler(component) == null)
        {
            val.Changing -= OnChanging;
            val.Changed -= OnChanged;
        }
    }
 
    public override void ResetValue(object component)
    {
    }
 
    public override void SetValue(object component, object value)
    {
    }
 
    public override bool ShouldSerializeValue(object component)
    {
        return false;
    }
 
    protected virtual void OnChanged(object sender, XObjectChangeEventArgs args)
    {
    }
 
    protected virtual void OnChanging(object sender, XObjectChangeEventArgs args)
    {
    }
}