The Class property does not exist in the namespace "http://schemas.microsoft.com/winfx/2009/xaml"

Question

The Class property does not exist in the namespace "http://schemas.microsoft.com/winfx/2009/xaml"

I create an application using Xamarin.Forms, and when I create a XAML page, I get the following error:

The "Class" property does not exist in the " http://schemas.microsoft.com/winfx/2009/xaml " namespace.

This is not the first page I have done, and all other pages work fine except for this. I checked the links and properties of the specified file and they all look fine.

Here is my code:

<?xml version="1.0" encoding="utf-8" ?> <controls:ViewPage xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="XXXX" xmlns:controls="XXXX" </controls:ViewPage>

The code is as follows:

 using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using XXXX; using Xamarin.Forms; namespace XXXX { public partial class ActOverviewView : ViewPage, IActOverviewView { public ActOverviewView() { InitializeComponent(); } } }