没有直接的方法可以做到这一点。下面我用CommunityToolkit.WinUI.UINuGet包中的FindDescendants()扩展方法给您演示一个例子。

private void MainPage_Loaded(object sender, RoutedEventArgs e)
{
    SetHeaderButtonFontSize(40);
    SetWeekDayNamesFontSize(40);
}

private void SetHeaderButtonFontSize(double fontSize)
{
    if (this.CalendarViewControl
        .FindDescendants()
        .OfType<Button>()
        .Where(x => x.Name == "HeaderButton")
        .FirstOrDefault() is not Button headerButton)
    {
        return;
    }

    headerButton.FontSize = fontSize;
}

private void SetWeekDayNamesFontSize(double fontSize)
{
    if (this.CalendarViewControl
        .FindDescendants()
        .OfType<Grid>()
        .Where(x => x.Name == "WeekDayNames")
        .FirstOrDefault() is not Grid weekDayNamesGrid)
    {
        return;
    }

    foreach (TextBlock child in weekDayNamesGrid.Children.OfType<TextBlock>())
    {
        child.FontSize = fontSize;
    }
}

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