a hideable toolbar item for xamarin forms apps

HideableToolbarItem.cs

using System;
using System.Threading.Tasks;
using Xamarin.Forms;

namespace MyXamarinForms.CustomControls
{
  /// <summary>
  /// This is a hideable toolbar item for xaml views. It operates by setting the
  /// text for the toolbar item to "" when it is invisible and removing the
  /// command so that it can't be clicked on.
  /// 
  /// When the toolbar item is made visible, the original settings are applied.
  /// </summary>
  public class HideableToolbarItem : ToolbarItem
  {
    public bool IsVisible
    {
      get { return (bool)GetValue(IsVisibleProperty); }
      set { SetValue(IsVisibleProperty, value); }
    }

    public static readonly BindableProperty IsVisibleProperty =
      BindableProperty.Create(nameof(IsVisible),
        typeof(bool),
        typeof(HideableToolbarItem),
        true,
        propertyChanged:OnIsVisibleChanged);

    private string oldText = "";
    private System.Windows.Input.ICommand oldCommand = null;

    private static void OnIsVisibleChanged(BindableObject bindable, object oldValue, object newValue)
    {
      var item = bindable as HideableToolbarItem;

      var newValueBool = (bool)newValue;
      var oldValueBool = (bool)oldValue;

      if (!newValueBool && oldValueBool)
      {
        item.oldText = item.Text;
        item.oldCommand = item.Command;
        item.Text = "";
        item.Command = null;
      }

      if(newValueBool && !oldValueBool){
        item.Text = item.oldText;
        item.Command = item.oldCommand;
      }
    }
  }
}

Usage of the control
<customControls:HideableToolbarItem Text="Func" Command="{Binding MyCommand}" IsVisible="{Binding ShouldShowCommand}"/>