WPF Sub-MenuItem Opening on the Left Instead of the Right

问题

I have set up a simple sample menu.

<Menu>
  <MenuItem Header="Top Menu">
    <MenuItem Header="Item 1">
      <MenuItem Header="Sub Menu 2" />
    </MenuItem>
  </MenuItem>
</Menu>

Sub Menu 2 is opening on the left instead of the expected right side of the menu. I would expect this behaviour if the menu was near the edge of the screen, but window is centered on the screen and not near any edge.

Is there a property that controls where a MenuItem opens on the screen?

回答1:

Does this happen on other applications on your system as well?

There's a registry setting in the value MenuDropAlignment in the key HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows that controls it system-wide. You might just check to make sure that it is set to 0 instead of 1.

More info can be found in this article.

来源：https://stackoverflow.com/questions/10454482/wpf-sub-menuitem-opening-on-the-left-instead-of-the-right