Develop Reference

Unable to Resolve Resources

I am using the MaterialDesign for XAML package in WPF. When I run my application, all styles and controls are rendered as expected. However in the XAML designer I have dozes of errors such as "The resource 'MaterialDesignFlatButton' could not be resolved." Example of a line that is throwing that error:
<Button Style="{StaticResource MaterialDesignFlatButton}" IsDefault="True" Margin="0 8 8 0" ...
My app.xaml contents is as follows:
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Light.xaml" />
<ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Defaults.xaml" />
<ResourceDictionary Source="pack://application:,,,/MaterialDesignColors;component/Themes/Recommended/Primary/MaterialDesignColor.Blue.xaml" />
<ResourceDictionary Source="pack://application:,,,/MaterialDesignColors;component/Themes/Recommended/Accent/MaterialDesignColor.LightBlue.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
I have attempted the top solution proposed on The resource "x" could not be resolved. but that causes the project to fail to run (I believe I am not using the correct pathing when attempting to use the proposed "absolute pack URI"). So I have two questions at this point:
Is there a reason the resources would fail to resolve in the XAML designer given the way I have defined them in App.xaml (per the developer guide: https://github.com/MaterialDesignInXAML/MaterialDesignInXamlToolkit/wiki/Getting-Started)?
How can I find out the "absolute pack URI" to use for the source for my resource dictionaries?

In the past, I had problems like this.
The error causes are as follow.
1. Setup and setting config
About this, please check the github and material design homepage.
2. Build and Compiler problem
About this, users may set the "Platform Target" as "x64".
That can invoke errors because material designer tool use "x32" compiler, so please use "any cpu" or "x32".

I had this problem with the flat accent button, while every other button style worked. I added the resource for buttons, then the error was gone. Then I removed the button resource... and the error was still gone.
https://github.com/MaterialDesignInXAML/MaterialDesignInXamlToolkit/wiki/FAQ
Exception: Cannot find resource named 'MaterialDesign...'
This error typically comes when you have a static resource referencing
one of the material design styles, and have not included the
appropriate resource dictionary that contains the style. Try the
following:
Ensure that you have loaded all of the default material design styles in your App.xaml. You can find directions for this in the
Getting Started guide.
Ensure you have referenced the control specific resource dictionary that contains the style. The path for this is resource dictionary
should be .xaml" />. For example, if you were trying to reference the
MaterialDesignFloatingActionMiniButton style for a button, the
resource dictionary source would be: . Typically these inclusions are done at root of your Window, User
Control, or Template. You can find the full list of the resource
dictionaries here

Window style not visible in designer

I created a Window style (WPF) and added it as a dll to my project
this style shows corretly when i run the program but doesn't show up in the designer.
I googled already but none of the solutions there are working
Test 1:
// Window //
Style="{DynamicResource HVE_Window}"
// Window.Resources //
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="pack://application:,,,/GlobalHive.Styles;component/HiveWindow.xaml"/>
</ResourceDictionary.MergedDictionaries>
Result:
Error: 'Window' TargetType doesn not match type of element 'WindowInstance'
-> But it runs and display correctly there
Test 2:
// Window //
Style="{DynamicResource MyWindow}"
// Window.Resources //
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="pack://application:,,,/GlobalHive.Styles;component/HiveWindow.xaml"/>
</ResourceDictionary.MergedDictionaries>
<Style x:Key="MyWindow" TargetType="{x:Type Window}" BasedOn="{StaticResource HVE_Window}" />
Result:
No Error:
Still doesn't display in the designer, still shows up if i run the program
Test 3:
Both versions but added to application resources
How it should look:
How it looks inside the designer:

You can sometimes find that resources from a control library are not loaded at design time, despite whatever you put in app.xaml to try and load the things.
MS created a mechanism for Blend which you can use in visual studio since it's the blend designer.
This uses a "special" resource dictionary called DesignTimeResources.xaml
This will only be used at design time.
Add one to the Properties of your problem exe project.
With exactly that name.
Put all your merges into that.
eg this is one of mine from my MapEditor project that uses numerous resources from UILib. UILib is a control library with all sorts of UI stuff in it.
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:MapEditor">
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="pack://application:,,,/UILib;component/Resources/Geometries.xaml"/>
<ResourceDictionary Source="pack://application:,,,/UILib;component/Resources/ControlTemplates.xaml"/>
<ResourceDictionary Source="pack://application:,,,/UILib;component/Resources/FontResources.xaml"/>
<ResourceDictionary Source="pack://application:,,,/UILib;component/Resources/UILibResources.xaml"/>
<ResourceDictionary Source="/Views/Drawing/Terrain/Resources/CityResources.xaml"/>
<ResourceDictionary Source="/Resources/MapEditorResources.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
Unload your csproj ( right click in solution explorer), edit it and find the node for that resource dictionary.
Change it to:
<Page Include="Properties\DesignTimeResources.xaml">
<SubType>Designer</SubType>
<Generator>MSBuild:Compile</Generator>
<ContainsDesignTimeResources>true</ContainsDesignTimeResources>
</Page>
Reload the project, close and re-open visual studio.
Your styles should now apply.

Cannot find ResourceDictionary when editing copy of template

please forgive me in advance. First question.
I am working on a WPF project where I have defined a simple resource dictionary at the application level.
<Application x:Class="Game.UI.Modals.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
StartupUri="MainWindow.xaml">
<Application.Resources>
<ResourceDictionary Source="GameResources.xaml"></ResourceDictionary>
</Application.Resources>
The reference to the ResourceDictionary is working fine; I am able to utilize it in XAML with no issues.
The problem I am having is in trying to add templates to the dictionary using the Create ControlTemplate Resource tool (right click => edit template => create empty). The Resource dictionary radio button in the define in panel is grayed out.
I have tried creating dictionaries in different namespaces, I made sure the dictionary is named and that the build action is set to resource.
Any idea how to get the Create ControlTemplate Resource dialog to recognize my application level ResourceDictionary?
Thanks!

Include your GameResources.xaml like this instead:
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="GameResources.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
The create template dialog lists the merged dictionaries. When you include your resources as in my example, the radiobutton should become enabled and your merged dictionary should appear in the list.

WPF Designer Failing to Load Generic.xaml

I have written a WPF Class Library. It has a Generic.xaml file under a themes folder in the project and also a ThemeInfo attribute in the AssemblyInfo.cs file:
[assembly: ThemeInfo(
ResourceDictionaryLocation.None,
ResourceDictionaryLocation.SourceAssembly)]
All works well, except in the designer. I get blue squigly lines anywhere I am using StaticResource to reference my brushes, styles and other resources saying:
The resource '[Resource Name]' cannot be found.
I really want the designer to pick up my Generic.xaml file and show the controls as I have styled them. How can I achieve this?
UPDATE
I have marked Yogesh's answer as correct but here is some more information. I was adding the resource dictionary in the constructor of the App.xaml file, instead of in the xaml. The XAML designer does not seem to execute the code behind for the App.xaml file.

Just add a new page named App.xaml with Application as the root element in the class library with Build Action set to Page. Now add the generic.xaml file as a resource dictionary. Something like this...
<Application x:Class="[YourNamespace].App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="[AbsoluteOrRelativePath]/Generic.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
</Application>
After you do this, rebuild your project, close all xaml views and reopen them again. This should fix your issue in VS2012/2013 and Blend 2012.

Have default string resource file and override it with custom ones

So the title is perhaps not completly clear.
I have a Strings.xaml file which contains several strings which are used in the application.
Strings.xaml
<!-- GENERAL FOR ALL TESTS -->
<my:String x:Key="AppTitle">AppName</my:String>
<my:String x:Key="TestName1">test_1</my:String>
<my:String x:Key="TestName2">test_2</my:String>
<!-- DEFAULT MESSAGES -->
<my:String x:Key="TestMessage">This is a default message</my:String>
<my:String x:Key="TestDescription">This is a default description</my:String>
<my:String x:Key="OnlyCustomInTest2">This string is used as a default message if not overridden by custom resource file</my:String>
</ResourceDictionary>
This resource file works great. What I'm wondering is if there is any built in way that I can use Strings.xaml as a default resource file and then override specific strings that are custom for different program modes? Like having Strings.xaml default and use Test_1_Strings.xaml and Test_2_Strings.xaml to override some strings for custom messages.
Test_1_Strings.xaml
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:my="clr-namespace:System;assembly=mscorlib">
<!-- CUSTOM FOR TEST 1 -->
<my:String x:Key="TestMessage">This is a message for test 1</my:String>
<my:String x:Key="TestDescription">This is a description for test 2</my:String>
</ResourceDictionary>
Test_2_Strings.xaml
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:my="clr-namespace:System;assembly=mscorlib">
<!-- CUSTOM FOR TEST 2 -->
<my:String x:Key="TestMessage">This is a message for test 2</my:String>
<my:String x:Key="TestDescription">This is a description for test 2</my:String>
<my:String x:Key="OnlyCustomInTest2">This is the overridden message for test 2</my:String>
</ResourceDictionary>
The reason I want to do this is because I have many different program modes where most of the resources are the same but some are custom. Instead of having to change a shared entry in 8 different resource files I could do it in only one place.

Resource lookup in WPF traverses from bottom to top i.e. any resource usage will first look for resource in its parent container which can be Grid, StackPanel etc. If not found in parent container will look for resource in parent's parent container and so on to UserControl, Window till it reach App resources.
Also, any resource later defined under resources section overrides the resource added previously with same key. This is true for resources defined under different resource dictionaries but not within the same XAML file. If you try to declare two items with same key, it will fail with key already exists exception.
You can take advantage of above stated features to your use.
Assuming you are merging the resources under App resources, what you can do is add Strings.xaml at top and then add other resource dictionaries Test_1_Strings.xaml and Test_2_Strings.xaml. This way resources with same name will be overridden and resource defined at last will always be resolved.
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Strings.xaml"/>
<ResourceDictionary Source="Test_1_Strings.xaml"/>
<ResourceDictionary Source="Test_2_Strings.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
So when you declare TextBlock to refer to StaticResource TestMessage.
<TextBlock Text="{StaticResource TestMessage}"/>
it will print This is a message for test 2.
If you change the order and add Test_1 after Test_2, textBlock Text will be - This is a message for test 1.