Xaml使用隐藏属性

Question

I have made a custom control which has a property X - which hides the VisualElement.X property of parent.

public class MyCustomControl : ContentView // is a distant child of VisualElement
{
    public new double X
    {
        get { return 0; }
        set { Console.WriteLine("I was not called with: " + value); }
    }
}

I set the X of the custom control in xaml:

<controls:MyCustomControl X="10" />

But here the Xamarin.Forms.VisualElement.X property setter is called instead of the MyCustomControl.X setter. Why? And how can I make it so my custom control property is used instead?

---

As a side note. When x:Name="myCustomControl and myCustomControl.X = 10 in code behind - then the setter of MyCustomControl is called.

---

When declaring property that does not exist in parent:

public double AnotherX
{
    get { return 0; }
    set { Console.WriteLine("Was called with: " + value); }
}

the setter is called. (From xaml).

Answer 1

This is because you are setting the BindableProperty 'X' of the VisualElement through the Xaml. It should work if you create a BindableProperty 'X' in your custom control as well.

Answer 2

1. You shouldn't be trying to override X you should be using a new name

2. you create a bindableproperty not just a property see below on how to make a bindable property

    private readonly BindableProperty CustomXProperty = BindableProperty.Create(nameof(CustomX), typeof(double), typeof(MyCustomControl), defaultValue: 0.0); public double CustomX { get { return (double)GetValue(CustomXProperty); } set { SetValue(CustomXProperty, value); } } 

Please see here for more information https://docs.microsoft.com/en-us/xamarin/xamarin-forms/xaml/bindable-properties