如何使用IDataErrorInfo。WPF程序中的错误?

I have an object like that:

我有一个这样的物体:

public class Person : IDataErrorInfo
{
    public string PersonName{get;set;}
    public int Age{get;set;}

    string IDataErrorInfo.this[string propertyName]
    {
        get
        {
            if(propertyName=="PersonName")
            {
                if(PersonName.Length>30 || PersonName.Length<1)
                {
                    return "Name is required and less than 30 characters.";
                }
            }
            return null;
        }
    }

    string IDataErrorInfo.Error
    {
        get
        {
            if(PersonName=="Tom" && Age!=30)
            {
                return "Tom must be 30.";
            }
            return null;
        }
    }
}
publ