WPF中绑定StaticResource的MenuItem图标显示为截断文本"pac.."

Hey there! Let's sort out that frustrating icon issue with your WPF MenuItem. I've run into this exact problem before, so I know what's going on here.

The Root Cause #

The Icon property of a MenuItem expects a UIElement (like an Image control) to display visually. But right now, you're binding directly to a BitmapImage—which is an ImageSource, not a visual element. WPF doesn't know how to render that as an icon, so it falls back to converting the BitmapImage to a string, which is why you see the truncated "pac.." (the start of your pack URI).

Simple Fixes to Try #

1. Wrap the BitmapResource in an Image Control

Keep your existing BitmapImage resource in App.xaml, but update your MenuItem to use an Image element as the Icon:

<MenuItem Header="_Tools">
    <MenuItem Header="_Settings" Click="MenuItem_Click">
        <MenuItem.Icon>
            <Image Source="{StaticResource Cog}" />
        </MenuItem.Icon>
    </MenuItem>
</MenuItem>

This tells WPF to render the image source properly as a visual icon.

2. Define an Image as Your Resource Instead

Alternatively, you can define the Image control directly in your resources, so you can bind it directly later:
First, update App.xaml:

<Application.Resources>
    <Image x:Key="CogIcon" Source="pack://application:,,,/Assets/Icons/cog.png" />
</Application.Resources>

Then use it in your MenuItem like this:

<MenuItem Header="_Tools">
    <MenuItem Header="_Settings" Click="MenuItem_Click" Icon="{StaticResource CogIcon}" />
</MenuItem>

Quick Check to Avoid Future Issues #

Make sure your image file's Build Action is set to Resource:

• Right-click the cog.png file in your project
• Go to Properties
• Under "Build Action", select "Resource"

This ensures the pack URI you're using can correctly access the image embedded in your application.

内容的提问来源于stack exchange，提问作者stigzler