c# – XML命名空间’clr-namespace：XYZ; assembly = XYZ’中不

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:sys="clr-namespace:System;assembly=mscorlib"
        xmlns:local="clr-namespace:WpfApplication1;assembly=WpfApplication1"
        Title="My First WPF Demo" Height="350" Width="525">
    <Window.Resources>
        <sys:Int32 x:Key="i">10</sys:Int32>
        <local:Employee x:Key="emp2"></local:Employee> --> THIS LINE
    </Window.Resources>
    <StackPanel>
        <TextBox x:Name="txtName" FontSize="18" Margin="20"></TextBox>
        <Button x:Name="btnClickMe" FontSize="18" Margin="20" 
                Click="btnClickMe_Click">Click Me</Button>
        <TextBlock x:Name="lblName" FontSize="18" Margin="20"></TextBlock>
        <Label x:Name="lblEmpInfo" FontSize="18" Margin="20"></Label>
        <Label x:Name="lblEmpInfo2" FontSize="18" Margin="20"></Label>
    </StackPanel>
</Window>

我在同一个项目中有一个类Employee,如下所示：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace WpfApplication1
{
    public class Employee
    {
        public int ID { get; set; }
        public string Name { get; set; }
    }
}

当我尝试构建我的项目时,我得到错误：

Error 1 The tag ‘Employee’ does not exist in XML namespace
‘clr-namespace:WpfApplication1;assembly=WpfApplication1’. Line 9
Position 10.