WPF Context Menu Doesn't Display on First Load

14 February 2008 00:00 AEST

C# .NET WPF

The problem

When using WPF OnContextMenuOpening, ContextMenu doesn’t display on first load.

The reason

The OnContextMenuOpening routed event is used for dynamically creating a ContextMenu object for a particular UIElement.

Each UIElement has a ContextMenu property which dictates what gets displayed when a user right-clicks on it. If the property is null, nothing will be displayed. If the property is not null, the context menu that it references will be displayed.

The catch? The ContextMenu property must not be null before the event handler first fires, or the menu won’t load. This appears to be a WPF bug.

The solution

Create an empty ContextMenu object and assign it to each UIElement that’s going to have any context menu displayed. In the OnContextMenuOpening event, either Clear() the existing context menu or just create a new one and assign the property to the object reference. Either will work.

Work

I'm at Octopus Deploy, helping to ship software that helps people ship software. Other interesting places I've been before Octopus include ThoughtWorks, Readify, Zap BI, Realex Payments and TRL.

I'm also a co-founder at Stack Mechanics, one of the organisers of the DDD Brisbane conference and, in my spare time (ha!), I also run my own photography business, Ivory Digital.

I'm a fan of high-quality code, domain-driven design, event-driven architecture, continuous delivery and, most importantly, shipping code that works and that solves people's problems.

I have a number of small open-source creations, including Nimbus, ConfigInjector and NotDeadYet, and am an occasional contributor to several more.

I'm a regular speaker and presenter at conferences and training events. My mother wrote COBOL on punch cards and I've been coding in one form or another since I was five years old.

Play

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