Accessing a resource via codebehind in WPF

Question

I have a custom collection defined in my window resources as follows (in a Sketchflow app so the window is actually a UserControl):

<UserControl.Resources>
    <ds:MyCollection x:Key="myKey" x:Name="myName" />
</UserControl.Resources>

I want to be able to refer to this collection in the codebehind, which I expected would be by the x:Name, but I can't seem to access it.

I can get a reference to it using

myRef = (MyCollection) this.FindName("myKey");

but this seems hackish. Is this bad practice, and what would be better? Thanks :)

Alexander Abakumov · Accepted Answer · 2016-11-03 22:41:58Z

106

You should use System.Windows.Controls.UserControl's FindResource() or TryFindResource() methods.

Also, a good practice is to create a string constant which maps the name of your key in the resource dictionary (so that you can change it at only one place).

edited Nov 3, 2016 at 22:41

Alexander Abakumov

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answered Jan 22, 2010 at 14:33

japf

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4 Comments

Tal Segal Over a year ago

You can use: Application.Current.FindResource(errorColorResourceName) as MyCollection or this.FindResource("RainbowBrush") as MyCollection. It depends on the context.

Mike Christiansen Over a year ago

Can you elaborate on "Also, a good practice is to create a string constant which maps the name of your key in the resource dictionary (so that you can change it at only one place)." ? Where would such a string constant go that would change the XAML key as well as the C# code behind?

tolache Over a year ago

+1 for > Can you elaborate on "Also, a good practice is to create a string constant which maps the name of your key in the resource dictionary (so that you can change it at only one place)." ? Where would such a string constant go that would change the XAML key as well as the C# code behind?

Poulpynator Over a year ago

@MikeChristiansen AdonisUI is a good exemple of that, if you look in src/AdonisUI/Brushes.cs you have a bunch of keys that are used in the templates, for example in Buttons.cs where you have a {DynamicResource {x:Static adonisUi:Brushes.ForegroundBrush}}.

Jakob Christensen · Accepted Answer · 2010-01-22 14:34:23Z

31

You may also use this.Resources["mykey"]. I guess that is not much better than your own suggestion.

answered Jan 22, 2010 at 14:34

Jakob Christensen

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3 Comments

cederlof Over a year ago

This is for Windows 8 Store Apps.

user5000935 Over a year ago

@cederlof, you can use this with WPF too.

John C Over a year ago

This will not work if the resource is in another file, for instance a theme color. FindResource is the way to go.

Nicke Manarin · Accepted Answer · 2014-10-28 13:32:42Z

24

Not exactly direct answer, but strongly related:

In case the resources are in a different file - for example ResourceDictionary.xaml

You can simply add x:Class to it:

<ResourceDictionary x:Class="Namespace.NewClassName"
                    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" >
    <ds:MyCollection x:Key="myKey" x:Name="myName" />
</ResourceDictionary>

And then use it in code behind:

var res = new Namespace.NewClassName();
var col = res["myKey"];

edited Oct 28, 2014 at 13:32

Nicke Manarin

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answered Jun 18, 2014 at 12:49

itsho

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3 Comments

Stephen Ross Over a year ago

+1, but to be able to find resources using it's key I had to call res.InitializeComponent() before attempting to access the key otherwise the object would show no keys and the call to res["myKey"] would return null.

sfaust Over a year ago

Wow that's awesome... I never knew you could do that and it just solved a problem for me quick and easy! I did need to call InitializeComponent() like @StephenRoss said but other than that works like a charm.

Brains Over a year ago

A perfect solution to use from Converters

Raman Sinclair · Accepted Answer · 2018-07-27 20:26:23Z

11

If you want to access a resource from some other class (i.g. not a xaml codebehind), you can use

Application.Current.Resources["resourceName"];

from System.Windows namespace.

answered Jul 27, 2018 at 20:26

Raman Sinclair

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1 Comment

Steven Rands Over a year ago

This is useful if you need to access the resource from a static constructor or method, and therefore don't have the ability to call FindResource or TryFindResource.

Johan Larsson · Accepted Answer · 2015-10-21 23:00:37Z

9

You can use a resource key like this:

<UserControl.Resources>
    <SolidColorBrush x:Key="{x:Static local:Foo.MyKey}">Blue</SolidColorBrush>
</UserControl.Resources>
<Grid Background="{StaticResource {x:Static local:Foo.MyKey}}" />

public partial class Foo : UserControl
{
    public Foo()
    {
        InitializeComponent();
        var brush = (SolidColorBrush)FindResource(MyKey);
    }

    public static ResourceKey MyKey { get; } = CreateResourceKey();

    private static ComponentResourceKey CreateResourceKey([CallerMemberName] string caller = null)
    {
        return new ComponentResourceKey(typeof(Foo), caller); ;
    }
}

answered Oct 21, 2015 at 23:00

Johan Larsson

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1 Comment

Mike de Klerk Over a year ago

Note that this depends on the type of key. E.g. a key in a DataTemplate is of type DataTemplateKey.

Ranier Jardim · Accepted Answer · 2019-11-24 02:24:21Z

1

I got the resources on C# (Desktop WPF W/ .NET Framework 4.8) using the code below

{DefaultNamespace}.Properties.Resources.{ResourceName}

answered Nov 24, 2019 at 2:24

Ranier Jardim

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Comments

Miyamoto Musashi · Accepted Answer · 2022-01-24 21:39:58Z

1

A nice clean example from Microsoft documents makes it simple:

private void myButton_Click(object sender, RoutedEventArgs e)
{
  Button button = (Button)sender;
  button.Background = (Brush)this.FindResource("RainbowBrush");
}

answered Jan 24, 2022 at 21:39

Miyamoto Musashi

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1 Comment

Honza Pačuta Over a year ago

This has already been answered.

Paul G Wichtendahl · Accepted Answer · 2025-07-08 19:21:56Z

I know this has been answered but with a more complex form. In this case it is a form with several grids and each one has its own styling resources I discovered the most efficient way to handle this involved two steps (mostly due to the fact that I forgot the adage "Scope matters"):

for accessibility give a name to the control holding the resources
Use the FindResource function of the control to set the child control

From the XAML

   <Grid x:Name="grdJIT">
        <Grid.Resources>
            <ResourceDictionary>
                <LinearGradientBrush x:Key="buttonStyleGradient"  EndPoint="0.5,1" StartPoint="0.5,0">
                    <GradientStop Color="White" Offset="0" />
                    <GradientStop Color="#FFACC3F5" Offset="1" />
                </LinearGradientBrush>
                <LinearGradientBrush x:Key="buttonStyleAlert"  EndPoint="0.5,1" StartPoint="0.5,0">
                    <GradientStop Color="Yellow" Offset="0" />
                    <GradientStop Color="#FFDD2375" Offset="1" />
                </LinearGradientBrush>
            </ResourceDictionary>
        </Grid.Resources>

then in the Code behind (to set the background of a button called "btnGetRG")

          LinearGradientBrush _r = (LinearGradientBrush)grdJIT.FindResource("buttonStyleAlert");
                            btnGetRG.Background = _r;

Like I said, the users question is answered previously and this is just a variant of that answer. I thought it worthwhile as my more specific search through Bing brought me here. Therefore, it seemed worth the post.

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