Xamarin Android - Checks if App needs to be updated, and if so takes the user to the Google Play Store.

DroidNeedUpdate.cs

private void GetUpdate()
{
	try
	{
		StartActivity(new Intent(Intent.ActionView, Android.Net.Uri.Parse("market://details?id=" + PackageName)));
	}
	catch (ActivityNotFoundException e)
	{
		// Default to the the actual web page in case google play store app is not installed
		StartActivity(new Intent(Intent.ActionView, Android.Net.Uri.Parse("https://play.google.com/store/apps/details?id=" + PackageName)));
	}
}

private async Task<bool> NeedUpdate()
{
	try
	{
		var curVersion = PackageManager.GetPackageInfo(PackageName, 0).VersionName;
		var newVersion = curVersion;

		string htmlCode;

		using (HttpClient client = new HttpClient())
		{
			htmlCode = await client.GetStringAsync("https://play.google.com/store/apps/details?id=" + PackageName + "&hl=en");
		}

		var doc = new HtmlAgilityPack.HtmlDocument();
		doc.LoadHtml(htmlCode);

		newVersion = doc.DocumentNode.SelectSingleNode("//div[@itemprop='softwareVersion']").InnerHtml.ToString();

		return String.Compare(curVersion, newVersion) < 0;
	}
	catch (Exception e)
	{
		Toast.MakeText(
			this, 
			"Trouble validating app version. Check your internet connection", 
			ToastLength.Long
		).Show();
		return true;
	}
}