datagrid中单元格颜色的动态更新

下午好。再次需要你的帮助。
以下代码无法正常工作：
XAML：

<DataGridTextColumn.CellStyle>
    <Style TargetType="DataGridCell">
        <Setter Property="Background" Value="{Binding Path=IsTypeCopied[0], Converter={StaticResource IntToBrushConverter}}"/>
    </Style>
</DataGridTextColumn.CellStyle>

IntToBrushConverter 类：

    class IntToBrushConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        bool b = (bool)value;
        if (b)
        {
            return Brushes.LightGreen;
        }
        else
        {
            return Brushes.Silver;
        }
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

还有一个实现 INotifyPropertyChanged 的​​ Worker 类

   public class Worker : INotifyPropertyChanged
{
    private bool[] _IsTypeCopied;

    public bool[] IsTypeCopied
    {
        get { return _IsTypeCopied; }
        set
        {
            _IsTypeCopied = value;
            OnPropertyChanged("IsTypeCopied");
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected void OnPropertyChanged(string propertyName)
    {
        var propertyChanged = PropertyChanged;
        if (propertyChanged != null)
        {
            propertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public Worker()
    {
        IsTypeCopied = new bool[7];
    }
}

IsTypeCopied 更改发生在以下函数中：

        private void gridWorker_MouseDoubleClick(object sender, MouseButtonEventArgs e)
    {
        int index;
        try
        {
            index = gridWorker.CurrentCell.Column.DisplayIndex;
        }
        catch (NullReferenceException)
        {
            return;
        }

        if (index < 6) return;

        Worker SelectedWorker = (Worker)gridWorker.SelectedItem;
        if (SelectedWorker.isSelected)
            SelectedWorker.IsTypeCopied[index - 7] = true;
    }

首次将列表加载到 DataGrid 中时，单元格的颜色为银色。但是将 IsTypeCopied 从 false 更改为 true 不会着色为 LightGreen。最有趣的是，如果 IsTypeCopied 是通过以下方式声明的：

private bool _IsTypeCopied;
    public bool IsTypeCopied
    {
        get { return _IsTypeCopied; }
        set
        {
            _IsTypeCopied = value;
            OnPropertyChanged("IsTypeCopied");
        }
    }

然后此代码按预期工作，但有 7 个单元格需要着色。我想通过一个数组来做到这一点。