若要使MaterialDesignThemes.Wpf.TimePicker不可键入，可以禁用控件的键盘输入。可以通过处理PreviewKeyDown事件并将事件参数的Handled属性设置为true以防止处理任何按键来实现此目的。下面是你可以修改你的代码的方法：

MaterialDesignThemes.Wpf.TimePicker timePicker = new MaterialDesignThemes.Wpf.TimePicker();
timePicker.Name = name.Replace("/", "000").Trim();
timePicker.Tag = name;
timePicker.Is24Hours = true;
timePicker.Style = (Style)Application.Current.Resources["MaterialDesignTimePicker"];
timePicker.PreviewTextInput += NumberValidationTextBox;
timePicker.PreviewKeyDown += (sender, e) =>
{
    // Prevent any keyboard input
    e.Handled = true;
};
timePicker.Margin = new Thickness(10);
timePicker.BorderThickness = new Thickness(1);
timePicker.HorizontalAlignment = HorizontalAlignment.Stretch;
timePicker.Foreground = Brushes.Black;

通过添加PreviewKeyDown事件处理程序并设置e.Handled = true;在它里面，你有效地阻止了TimePicker中的任何键盘输入，使其不可键入，同时仍然允许用户从时钟中选择时间。