我可以在表单中复制它。当IsPassword更改时，光标会移到第一个位置。
我分享了一个使用Custom Renderer的解决方法，包括以下步骤：

创建自定义入口控件

public class MyCustomEntry : Entry
{
    public MyCustomEntry()
    {
    }
}

使用自定义控件

• xaml文件 *

<local:MyCustomEntry x:Name="myentry" 
       Text="{Binding Password}" Keyboard="Plain"        
    />
<ImageButton x:Name="previewPasswordButton"
            Pressed="previewPasswordButton_Pressed"
            Released="previewPasswordButton_Released" />

• cs文件 *，我使用MessagingCenter向native类发送消息：

void previewPasswordButton_Released(System.Object sender, System.EventArgs e)
{
    MessagingCenter.Send<MainPage,bool>(this, "button",false);
}

void previewPasswordButton_Pressed(System.Object sender, System.EventArgs e)
{
    MessagingCenter.Send<MainPage,bool>(this, "button",true);
}

创建Android平台自定义渲染器

[assembly: ExportRenderer(typeof(MyCustomEntry), typeof(MyCustomEntryRenderer))]
namespace EntryIsPassword77045393.Droid
{
    public class MyCustomEntryRenderer: EntryRenderer
    {

        int cursor_position;
        public MyCustomEntryRenderer(Context context) : base(context)
        {
            MessagingCenter.Subscribe<MainPage, bool>(this, "button", (s, e) =>
            {
                if(e)
                {
                    cursor_position = Control.SelectionStart;
                    Control.TransformationMethod = null;        
                    Control.SetSelection(cursor_position);
                }
                else
                {
                    cursor_position = Control.SelectionStart;
                    Control.TransformationMethod = PasswordTransformationMethod.Instance;
                    Control.SetSelection(cursor_position);
                }
            });
        }

        protected override void OnElementChanged(ElementChangedEventArgs<Entry> e)
        {
            base.OnElementChanged(e);           
        }         
    }
}

希望有帮助。