编辑TextBlock时出现InvalidOperationException。OnTextChanged内部的内联线已更改

在下面的代码中,我随机遇到了InvalidOperationException,有什么好方法可以修复它?

public class ParsedTextBlock : TextBlock
{
    static ParsedTextBlock() {
        TextProperty.OverrideMetadata(typeof(ParsedTextBlock),
            new FrameworkPropertyMetadata("No Text Set",
                FrameworkPropertyMetadataOptions.AffectsMeasure | FrameworkPropertyMetadataOptions.AffectsRender,
                OnTextChanged)
            );
    }

    private static void OnTextChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
    {
        ParsedTextBlock control = (ParsedTextBlock)obj;
        control.Inlines.Clear();
        control.Inlines.Add(new Run("test " + args.NewValue as string))
    }
}