How can I make a template call a method? - xamarin

Question

I have this template:
<?xml version="1.0" encoding="utf-8"?>
<ViewCell xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="Japanese.OpenPageTemplate"
x:Name="this">
<Label Text="ABC" VerticalTextAlignment="Center" />
</ViewCell>
and the code behind:
using System;
using System.Collections.Generic;
using Xamarin.Forms;
namespace Japanese.Templates
{
public partial class OpenPageTemplate : ViewCell
{
public OpenPageViewCellTemplate()
{
InitializeComponent();
}
protected override void OnTapped()
{
base.OnTapped();
// I need to call openPage() here or at least have openPage() called from the place where the template is used.
}
}
}
Can someone tell me how I can make this template call a method called openPage() when the user taps on the ViewCell? In a previous question there was an answer about using the .Invoke method that went something like this:
ClickAction?.Invoke(this, new EventArgs());
However this time there's just one action to invoke and I don't need to pass information on the action into ClickAction.

Answer 1

Wrap the ViewCell in a DataTemplate:
<?xml version="1.0" encoding="utf-8" ?>
<DataTemplate xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:template="clr-namespace:Japanese"
x:Class="Japanese.OpenPageTemplate">
<ViewCell Tapped="OnOpenPageTapped">
...
</ViewCell>
</DataTemplate>
Codebehind:
namespace Japanese
{
public partial class OpenPageTemplate : DataTemplate
{
public OpenPageTemplate ()
{
InitializeComponent ();
}
private void OnOpenPageTapped(object sender, EventArgs e)
{
//example: template is an itemtemplate for a list of class A.B with property C
var c = ((sender as ViewCell)?.BindingContext as A.B)?.C;
}
...

Answer 2

Subscribe to the desired Cell.Tapped Event and invoke the action when the event is raised.
XAML
<template:OpenPageTemplate Tapped="OnOpenPageTapped" />
Code behind
private void OnOpenPageTapped(object sender, EventArgs args) {
openPage();
}
assuming that openPage() is accessible from the place where the template is used.