您可以设置如下填充：

public class MyEntryRenderer : EntryRenderer
        {
            protected override void OnElementChanged (ElementChangedEventArgs<Entry> e)
            {
                base.OnElementChanged (e);
    
                if (Control != null) {
            Control.LeftView = new UIView(new CGRect(0,0,15,0));
            Control.LeftViewMode = UITextFieldViewMode.Always;
            Control.RightView = new UIView(new CGRect(0, 0, 15, 0));
            Control.RightViewMode = UITextFieldViewMode.Always;
                }
            }
}

编辑器的工作范围：

在框架中扭曲编辑器并设置填充，如下所示：

<StackLayout Margin="20">
    <Frame CornerRadius="10" BorderColor="Gray" HeightRequest="50" Padding="5,10,5,10" HasShadow="False">
        <Editor Placeholder="Enter the editor text" ></Editor>
    </Frame>
</StackLayout>

基础UITextView不实现Placeholder。但是，如果查看从UITextView派生的EditorRenderer代码，就会发现Xamarin已在此处实现了Placeholder。

private UILabel _placeholderLabel;

通过使用反射，我可以获得一个指向UILabel _placeholderLabel的指针，但我无法移动它。
如果有人能帮我移动UILabel，我相信我们就有了答案！

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

    if (Control != null)
    {
        editor = e.NewElement as EditorEx;

        //Use reflection to access private placeholder in parent
        //https://www.c-sharpcorner.com/UploadFile/6f0898/how-to-access-a-private-member-of-a-class-from-other-class/
        System.Reflection.FieldInfo receivedObject = typeof(EditorRenderer).GetFields(System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance)[1];

        _placeholderLabel = receivedObject.GetValue(this) as UILabel;

        _placeholderLabel.Text = "move me!!; //this works
        _placeholderLabel.BackgroundColor = UIColor.Green; //this works

        //put it on another message to see if that solves it (it doesn't)
        Device.BeginInvokeOnMainThread(() =>
        {
            //HELP NEEDED HERE!!!
            //_placeholderLabel.Frame = new CGRect(-15, -10, 500, 30); //doesn't work
            //_placeholderLabel.Bounds = new CGRect(-15, -10, 500, 30); //doesn't work
            _placeholderLabel.LayoutMargins = new UIEdgeInsets(-15, -10, 5, 5); //doesn't work

        });
    }
}