Reference custom resource defined in another xaml file

Question

I am trying to create a new resource in one xaml file and reference it in another xaml file. i.e I define

<Window.Resources>
    <ImageBrush x:Key="TileBrush" TileMode="Tile" ViewportUnits="Absolute" Viewport="0 0 32 32" ImageSource="MyImageButton.png" Opacity="0.3">
    </ImageBrush>
</Window.Resources>

And attempt to use it in another xaml file by

<Grid>
    <Button Background="{StaticResource TileBrush}" Margin="5" Padding="5" FontWeight="Bold" FontSize="14">
        A Tiled Button
    </Button>
</Grid>

However I get the error "StaticResource reference 'TileBrush' was not found." I can reference the resource from the same xaml file but don't know how to do so from another file.

Answer 1

In WPF, the resource references works as a tree. Each control have resource, and children control can access parent's resources. The global application resource dictionary is in the App.xaml file. In this file you can include several resource dictionaries as a Merged Dictionary. See this code sample:

<?xml version="1.0" encoding="utf-8"?>
<Application ...>
    <Application.Resources>
        <ResourceDictionary>
            <vm:ViewModelLocator x:Key="Locator" d:IsDataSource="True" />
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="View\SomeFileDictionary.xaml"/>
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>

The SomeFileDictionary.xaml is located in the View folder of my project structure. And has looks like this:

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                xmlns:ViewModel="clr-namespace:Cepha.ViewModel"
                xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
                ... >

<DataTemplate DataType="{x:Type ViewModel:SomeType}">
    <TextBox .../>
</DataTemplate>...

And each dictionary key or data template defined in this file (or App.xaml), can be referenced in any place of your project. Hope this helps...