TeamMateItem.cs

class TeamMateItem : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    protected bool SetPropertyValue<T>(ref T field, T value, [CallerMemberName] string propertyName = null)
    {
        if (Equals(field, value)) return false;

        field = value;
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        return true;
    }

    private string _name;

    public string Name
    {
        get => _name;
        set => SetPropertyValue(ref _name, value);
    }

    private uint _level;

    public uint Level
    {
        get => _level;
        set => SetPropertyValue(ref _level, value);
    }
}