CODEWITHSUNDEEP
c#mobilexamarinwindows-phone-8.1xamarin.forms
Orlando
Orlando

Reputation: 975

Custom picker renderer draw event not recognized in Xamarin.Forms for WinPhone

I am trying to customize Xamarin.Forms picker control. In android and ios I am overriding the Draw event and drawing the control myself. However on the WinPhone 8.1 project I am unable to override the Draw event because it is not recognized. Below is the code I am using in android and ios and a screen capture of the WinPhone project showing that the draw event doesnt exist.

Android

using Android.Graphics;
using Namespace.CustomControls;
using Namespace.Droid.Renderers;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;

[assembly: ExportRendererAttribute(typeof(BindablePicker), typeof(BindablePickerRenderer))]
namespace Namespace.Droid.Renderers
{
    public class BindablePickerRenderer : PickerRenderer
    {
        public BindablePickerRenderer()
        {
            this.SetWillNotDraw(false);
        }

        protected override void OnElementChanged(ElementChangedEventArgs<Picker> e)
        {
            base.OnElementChanged(e);
            this.Element.PropertyChanged += (s_, e_) => Invalidate();
        }

        public override void Draw(Canvas canvas)
        {
            BindablePicker bp = (BindablePicker)this.Element;

            // Code to draw my control
        }
    }
}

IOS

using System;
using System.Collections.Generic;
using System.Text;
using CoreGraphics;
using Xamarin.Forms.Platform.iOS;
using Namespace.CustomControls;
using UIKit;
using Xamarin.Forms;
using Namespace.iOS.Renderers;

[assembly: ExportRendererAttribute(typeof(BindablePicker), typeof(BindablePickerRenderer))]
namespace Namespace.iOS.Renderers
{
    public class BindablePickerRenderer : PickerRenderer
    {
        protected override void OnElementChanged(ElementChangedEventArgs<Picker> e)
        {
            base.OnElementChanged(e);
            this.Element.PropertyChanged += (s_, e_) => SetNeedsDisplay();
        }
        public override void Draw(CGRect rect)
        {
            BindablePicker bp = (BindablePicker)this.Element;

            // Code to draw my control
        }
    }
}

WinPhone

The only event available is OnApplyTemplate

If anyone has any idea on how I can get into the draw event of this control on the Windows Phone 8.1 platform I'd greatly appreciate it.

Thanks in advance.

Upvotes: 0

Views: 1283

Answers (1)

Pete
Pete

Reputation: 4746

WindowsPhone does not have direct drawing abilities.

You will want to create a control hierarchy of some sort to get around your needs for the Windows Phone platform.

If you want to do custom drawing, use something like a WriteableBitmap and render into an image control for example.

Alternatively maybe look at NGraphics, with a wrapper control for it for Xamarin.Forms here.

Upvotes: 2

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