Entry render not adding underline in iOS Xamarin Forms - xamarin.forms

Question

I have an Entry in Xamarin Forms and for Android, its displayed with an underline by default and when I test it for iOS it's always with a rectangle like this:
And I want it to be like just like in Android:
I used Custom render where I specified that I want an underline but its still displayed in a rectangle. This code doesn't work:
class MyEntryRenderer : EntryRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<Entry> e)
{
base.OnElementChanged(e);
if (Control != null)
{
Control.BorderStyle = UITextBorderStyle.Line;
}
}
}
I have solved this problem with the next code:
class MyEntryRenderer : EntryRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<Entry> e)
{
base.OnElementChanged(e);
if (Control != null)
{
Control.BorderStyle = UITextBorderStyle.None;
//Create borders(bottom only)
CALayer border = new CALayer();
float width = 2.0f;
border.BorderColor = Color.FromHex(ColorConstants.BlueHex).ToCGColor();
border.Frame = new CGRect( 0, 40, 400, 2.0f);
border.BorderWidth = width;
Control.Layer.AddSublayer(border);
Control.Layer.MasksToBounds = true;
}
}
}
But still, don't understand why the previous code doesn't work, it should be simple as that. Any ideas?

Answer 1

https://developer.xamarin.com/api/type/UIKit.UITextBorderStyle/
The enum values for UITextBorderStyle are Bezel, Line, None, and RoundedRect. All of them (except for None) simply describe the style of the border that goes around the entire UITextView, so the Line value doesn't mean a single line, it means a solid line rectangle around the entire view, as opposed to a Bezel or rounded rectangle.

Answer 2

the implementation witch has solved the user question didn't work for me in these days, but this one has worked: https://social.msdn.microsoft.com/Forums/en-US/7ae2e5ad-3cc4-4761-ac39-06e8d8842cf4/entry-bottom-line?forum=xamarinforms
as jmoerdyk gently suggested this link explains how to write a custom renderer for iOS to render an entry with a bottom line instead of a complete border. the color of the line will change when the entry has focus.
below the piece of code with some null checks:
public class IOSBottomLineEntryRenderer : EntryRenderer
{
private CALayer _borderLayer;
protected override void OnElementChanged(ElementChangedEventArgs<Entry> e)
{
base.OnElementChanged(e);
if (Control == null)
return;
Control.BorderStyle = UITextBorderStyle.None;
if (Element == null)
return;
DrawBorder(UIColor.FromRGB(156, 156, 156));
e.NewElement.Unfocused += (_, _) =>
{
DrawBorder(UIColor.FromRGB(156, 156, 156));
};
e.NewElement.Focused += (_, _) =>
{
DrawBorder(UIColor.FromRGB(245, 0, 47));
};
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (Control == null)
return;
if (Element == null)
return;
DrawBorder(UIColor.FromRGB(156, 156, 156));
}
public override CGRect Frame
{
get { return base.Frame; }
set
{
base.Frame = value;
if (Control == null)
return;
if (Element == null)
return;
DrawBorder(UIColor.FromRGB(156, 156, 156));
}
}
private void DrawBorder(UIColor borderColor)
{
if (Frame.Height <= 0 || Frame.Width <= 0)
return;
if (_borderLayer == null)
{
_borderLayer = new CALayer
{
MasksToBounds = true,
Frame = new CGRect(0f, Frame.Height - 1, Frame.Width, 1f),
BorderColor = borderColor.CGColor,
BorderWidth = 1.0f
};
Control.Layer.AddSublayer(_borderLayer);
Control.BorderStyle = UITextBorderStyle.None;
}
else
{
_borderLayer.BorderColor = borderColor.CGColor;
_borderLayer.Frame = new CGRect(0f, Frame.Height - 1, Frame.Width, 1f);
}
}
}