The CommandBar control is a vital component of UWP app design. It is an evolution of the AppBar concept, which was available ever since Windows Phone 7, but with UWP is much more feature complete. One thing that is still missing however is the option to choose the direction in which the command bar opens.

Problem

The default behavior of the CommandBar is to open in the up direction whenever the control is not at the very top of the window. This is an issue, because this holds true even when we define a custom title bar on Desktop, in which case the CommandBar opens below the window's minimize, maximize and close buttons which doesn't look good at all.

The default template

The default template of the CommandBar control defines the states of the control as a collection of VisualStates and VisualStateTransitions . It turns out that there is always a separate visual state for down and up direction.

Inside these states you can see that the system just uses different values for some of the properties like CommandBarTemplateSettings.ContentHeight vs CommandBarTemplateSettings.NegativeOverflowContentHeight for the Y property of OverflowContentRootTransform .

Solution

We cannot easily change the inner logic of the control itself, but we can make the control in up-open state look identical as it does for down-open state. This can be achieved purely by copy-pasting the Storyboards from ...OpenDown visual states and visual state transitions to the respective ...OpenUp counterparts. Unfortunately the manual copy-pasting is the only option, because extracting the Storyboards into separate resources and referencing them with isn't supported. To get a full copy of the default control style you can use either the XAML Designer (right-click the control, select Edit Template and Edit a Copy...), or search for it in C:\Program Files (x86)\Windows Kits\10\DesignTime\CommonConfiguration\Neutral\UAP\Generic\generic.xaml To spare your Ctrl , C and V keys, I have prepared the full modified style which you can take and use in your app. You can get this style here on my GitHub along with the full sample project for this article. Beware that this style targets the Anniversary Update. I recommend doing the changes manually if you target a different version.

Summary

The CommandBar is a great control that works as we expect most of the time. When we hit an issue however, its template is quite easy to modify.