C# 为什么我会得到；类型引用找不到公共类型“；关于这个数据绑定？

为什么在本例中，ObjectDataProvider没有识别“local:Customer”

我打字的时候

“x:Type”是一个标记扩展，因此请将其用大括号括起来：

ObjectType="{x:Type local:Customer}"

尝试添加名称空间作为类的前缀

using System.Collections.ObjectModel;

namespace TestDataTemplate124
{
    public class Customer
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int Age { get; set; }

        public static ObservableCollection<Customer> GetAllCustomers()
        {
            ObservableCollection<Customer> customers = new ObservableCollection<Customer>();
            customers.Add(new Customer() { FirstName = "Jim", LastName = "Smith", Age = 23 });
            customers.Add(new Customer() { FirstName = "John", LastName = "Jones", Age = 22 });
            customers.Add(new Customer() { FirstName = "Jay", LastName = "Anders", Age = 21 });
            return customers;
        }
    }
}

ObjectType="{x:Type local:Customer}"