WPF compile error "IDictionary must have a Key attribute"

Question

I've created control styles I want to use among multiple xaml pages in my WPF app. To do this I created a Resources.xaml and added the styles there.

Then in my pages I add this code

<Grid.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="pack://application:,,,/SampleEventTask;component/Resources.xaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Grid.Resources>

On two pages this works fine, but on the 3rd page I get a compile error that says:

All objects added to an IDictionary must have a Key attribute or some other type of key associated with them.

If I add a key to this, as such ResourceDictionary x:Key="x", then the compile error goes but on running the app it errors finding the style.

I can make the compile error go away and have the app run by just moving original (no key specified) "ResourceDictionary" xaml from the top level Grid into a contained Grid on that page.

But I don't understand what is going on here. Any suggestions as to what the problem is, I'm just missing something or doing something incorrectly. Is there a better way to share styles?

thanks

possible duplicate of [Can you define a ResourceDictionary.MergedDictionary together with other (local) resources in ?](http://stackoverflow.com/questions/2695849/can-you-define-a-resourcedictionary-mergeddictionary-together-with-other-local) — Dzyann, Jun 03 '15 at 13:59

score 8 · Answer 1 · answered May 28 '10 at 19:25

Are there any other resources defined other than the merged ResourceDictionary in that Page?

For example, here's a snippet from a Window I created.

<Window x:Class="SelectionPagePrototype.SelectionPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:SelectionPagePrototype"
    Title="SelectionPage" MinHeight="600" MinWidth="800" Loaded="OnLoaded">
    <Window.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="ImageResourceDictionary.xaml" />
            </ResourceDictionary.MergedDictionaries>
            <local:QuickPickCheckedConverter x:Key="quickPickConverter" />
            <local:BoolToCaptionConverter x:Key="captionConverter" />
            <local:ProductAndImageTypeConverter x:Key="imageConverter" />
        </ResourceDictionary>
    </Window.Resources>
    <Grid> ...

The merged dictionary did not require a key, but the other resources for that Window do.

Thanks for pointing out `x:Key`. I was getting that error by using `x:Name`. — thehelix, Nov 29 '17 at 01:27

score 0 · Answer 2 · answered Aug 23 '23 at 12:47

In my case, the issue was that the was not the first item in the <Grid.Resources>, so even if all of the other items had a Key defined, the error was popping up at compile time. By moving the Resource Dictionary as the first item in the resources, the project compiles successfully.

WPF compile error "IDictionary must have a Key attribute"

2 Answers2

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