如何在xamarin表单中向自动完成字段添加占位符颜色属性？

<Label Text="Search" TextColor="Gray" />
<Entry Placeholder="Enter search keyword" PlaceholderColor="Gray" />

using Android.Content;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;

[assembly: ExportRenderer(typeof(Entry), typeof(CustomEntryRenderer))]
namespace YourNamespace
{
    public class CustomEntryRenderer : EntryRenderer
    {
        public CustomEntryRenderer(Context context) : base(context)
        {
        }

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

            if (Control != null)
            {
                Control.SetHintTextColor(Android.Graphics.Color.Gray);
            }
        }
    }
}

using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

[assembly: ExportRenderer(typeof(Entry), typeof(CustomEntryRenderer))]
namespace YourNamespace
{
    public class CustomEntryRenderer : EntryRenderer
    {
        protected override void OnElementChanged(ElementChangedEventArgs<Entry> e)
        {
            base.OnElementChanged(e);

            if (Control != null)
            {
                Control.Placeholder = "Enter search keyword";
                Control.SetValueForKeyPath(UIColor.Gray, new NSString("_placeholderLabel.textColor"));
            }
        }
    }
}