Context menu is cut in some situations in WPF

Question

Context menu is truncated in different .NET Framework. See images inside ZIP file (there are two screenshots, one from XP and other from Win7).

I created a simple Visual Studio 2010 solution which repro my issue.

( http://www.mediafire.com/download.php?doq7gsh75qgvzwq ).

On XP it seems to work fine, but not on Windows 7.

The issue can be reproduced on Windows 7 if target .NET Framework is 3.5 (including SP1) (please see the image from zip).

If I change the target framework to 4.0 it works fine also on Windows 7.

Is a solution to make context menu full visible in .NET Framework 3.5 on Windows 7 OS ?

Curious behavior... it really happens as you say. Curiously for me it happens the most if running inside Visual Studio. Still it happens SOMETIMES when VS is not running. For me this is a good candidate for Connect. — NestorArturo, Mar 16 '12 at 20:13
Unable to reproduce. Possibly because I have .Net 4.5 installed? — Phil, Mar 17 '12 at 10:17
Unable ? Please set .NET Framework 3.5 in project target framework and try again. Only in Windows 7. Not XP. — Snake Eyes, Mar 18 '12 at 08:10
Yes I had target framework set to 3.5, running on Windows 7. — Phil, Mar 19 '12 at 12:01
I cannot reproduce on my machine. Have you tried changing windows themes and checking what happens. Could be a problem with the template for the current theme. — NVM, Mar 19 '12 at 18:27
Yes, I changed to basic theme but same problem. But changing theme is not workaround. — Snake Eyes, Mar 20 '12 at 06:08
Yes its not a work around. The aim of the suggestion was to find the root cause of the problem. Once you know the problem finding a solution will be easy. — NVM, Mar 20 '12 at 07:19
Have you SP1 for VS2010 installed? It works perfectly on my Win7/x64 — asktomsk, Mar 21 '12 at 15:16
With maximized window ? Try with modified-size window ! There is the problem ! — Snake Eyes, Mar 21 '12 at 15:42

score 4 · Accepted Answer · answered Mar 17 '12 at 10:46

It seems that when the ContextMenu is loaded the ScrollContentPresenter for the menu isn't sized correctly, clipping the ItemPresenter of the MenuItems (Below is an abridged version of the visual tree showing the issue).

PopupRoot, Acutal Width: 219,027, Desired Width: 219,027
    Decorator, Acutal Width: 219,027, Desired Width: 219,027
        NonLogicalAdornerDecorator, Acutal Width: 219,027, Desired Width: 219,027
            ContextMenuProxy, Acutal Width: 219,027, Desired Width: 219,027
                SystemDropShadowChrome, Acutal Width: 214,027, Desired Width: 219,027
                    Border, Acutal Width: 214,027, Desired Width: 214,027
                        Grid, Acutal Width: 212,027, Desired Width: 212,027
                            Rectangle, Acutal Width: 28,000, Desired Width: 32,000
                            Rectangle, Acutal Width: 1,000, Desired Width: 31,000
                            Rectangle, Acutal Width: 1,000, Desired Width: 32,000
                            ScrollViewer, Acutal Width: 210,027, Desired Width: 212,027
                                Grid, Acutal Width: 210,027, Desired Width: 210,027
                                    Border, Acutal Width: 210,027, Desired Width: 210,027
                                        ScrollContentPresenter, Acutal Width: 210,027, Desired Width: 210,027
                                            ItemsPresenter, Acutal Width: 241,047, Desired Width: 245,047

Invalidating the measure of the of the ContextMenu's visual root (the PopupRoot) when the menu is loaded should cause the layout to be updated to display the correct bounds for the ItemsPresenter.

The handler for the menu's Load event:

private void mainMenu_Loaded(object sender, RoutedEventArgs e)
{
    if (sender != null)
    {
        ContextMenu menu = sender as ContextMenu;
        if (menu != null)
        {
           // get the visual root for the context menu
           var root = (FrameworkElement)GetVisualTreeRoot(menu);

           // invalidate the menu's layout
           root.InvalidateMeasure();
        }             
    }
}

GetVisualTreeRoot method:

private DependencyObject GetVisualTreeRoot(DependencyObject control)
{
    DependencyObject parent = VisualTreeHelper.GetParent(control);
    if (parent != null)
    {
        return GetVisualTreeRoot(parent);
    }
    else
    {
        return control;
    }
}

I awarded you because this is a good workaround. I will try in few days if something works. If yes, the answer will be marked as accepted. Thank you for patience. — Snake Eyes, Mar 23 '12 at 14:12

score 1 · Answer 2 · answered Mar 16 '12 at 20:17

1

A workaround:

<ContextMenu x:Name="mainMenu" Width="300" >

It seems to stop bothering when setting a fixed width. Still a good candidate for Connect.

answered Mar 16 '12 at 20:17

NestorArturo

2,476
1
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This is not a solution. What happens if I insert long words ? – Snake Eyes Mar 20 '12 at 06:07
Yes... it is not. It's a workaround. As it seems to be an incorrect behavior and need fixing from MS, all you might get are workarounds :o) – NestorArturo Mar 20 '12 at 13:53
1

Of course, you can also limit the size of menu items so they have to wrap the text inside. – NestorArturo Mar 20 '12 at 14:00

score 0 · Answer 3 · answered Jul 14 '14 at 05:32

I am able to reproduce this issue in .Net 4.5.1 also. Not able to solve using above marked solution as well. InvalidateMeasure still results in empty context menu sometimes and it starts appearing. When I snoop the context menu, found out that menu ItemsPanel size calculation is done fine, but ScrollContentPresenter size is 0.Anyone facing similar issues. My workaround is :

    private static void ContextMenuOnLoaded(object sender, RoutedEventArgs routedEventArgs)
    {
        var menu = (ContextMenu)sender;
        if (menu.HasItems)
        {
            menu.MinHeight = menu.Items.Count * 25;
        }

        menu.Loaded -= ContextMenuOnLoaded;
    }

Not sure if it is the best solution. But why does it happen is also surprising.

Context menu is cut in some situations in WPF

3 Answers3

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