My project uses a ProjectTheme.xaml file for all WPF windows through out the project.
The ProjectTheme.xaml file references a style theme as follows
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ResourceDictionary.MergedDictionaries>
<!-- In order to modify the project's theme, change this line -->
<ResourceDictionary Source="/MyProject;component/Themes/WPFThemes/Customized.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
All WPF Windows references WindowBase.xaml
<Window.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/MyProject;component/View/WindowBase.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Window.Resources>
WindowBase.xaml references customized titlebar Bar1.xaml
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/MyProject;component/Themes/WPFThemes/Bar1.xaml" />
</ResourceDictionary.MergedDictionaries>
Bar1.xaml references ProjectTheme.xaml
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/MyProject;component/ProjectTheme.xaml"/>
</ResourceDictionary.MergedDictionaries>
So the heriarchy is
Window1 references WindowBase.xaml
WindowBase references Bar1.xaml
Bar1 references ProjectTheme.xaml
ProjectTheme.xaml reference the real theme resource file.
This works fine.
Now I want to dynamically change the project theme at run time without quitting the app.
Assuming that I have several theme style files
Customized.xaml
Customized1.xaml
Customized2.xaml
My question is
if it possible to dynamically update ProjectTheme.xaml file at run time to change the line
from
<ResourceDictionary Source="/MyProject;component/Themes/WPFThemes/Customized.xaml" />
to
<ResourceDictionary Source="/MyProject;component/Themes/WPFThemes/Customized1.xaml" />
to achieve my objective?
If yes, how do I do it?
If no, what is the reason and what is the best (other) way to achieve my purpose?
I have tried the following but none of them work: the style does not change.
way 1
Application.Current.Resources.MergedDictionaries.Clear();
Uri NewTheme = new Uri(#"/MyProject;component/Themes/WPFThemes/Customized2.xaml", UriKind.Relative);
ResourceDictionary dictionary = (ResourceDictionary)Application.LoadComponent(NewTheme);
Application.Current.Resources.MergedDictionaries.Add(dictionary);
way 2
Application.Current.Resources.MergedDictionaries.RemoveAt(0);
Uri NewTheme = new Uri(#"/MyProject;component/Themes/WPFThemes/Customized2.xaml", UriKind.Relative);
ResourceDictionary dictionary = (ResourceDictionary)Application.LoadComponent(NewTheme);
Application.Current.Resources.MergedDictionaries.Insert(0, dictionary);
Note:
In my real theme style files (Customized.xaml...) I used a combination of dynamic resource and static resource. Does that matters?
Thanks in advance.
There are a few things to consider here.
First, anything defined with StaticResource will not get updated on a change. If you want a control to support changing the theme at runtime, you need to use DynamicResource so it knows to look for changes.
Your overall approach to changing the theme is correct. The easiest way to accomplish this is using Application-scoped resource dictionaries, making sure your ResourceDictionary is defined in your App.xaml. For adding a new resource, I've used snippets similar to the following:
ResourceDictionary dict = new ResourceDictionary();
dict.Source = new Uri("MyResourceDictionary.xaml", UriKind.Relative);
Application.Current.Resources.MergedDictionaries.Add(dict);
The part you may be confusing yourself over is when using resources within base classes. When you define a resource in a class, the resource will be local to an instance of that type. Think of the XAML compiling into it's own InitializeComponent() method on classes, meaning you can't change the original XAML and expect the changes to go to all instances. On the same note, changing the resources on a class instance doesn't effect other instances.
Since your question really contains two separate concerns (application theming and changing control resources), I would focus on ensuring your application resources are updating properly and using DynamicResource, and hopefully the information I've provided would be sufficient for understanding why certain other resources may not be updating yet.
Related
I have a class library I am creating for an AutoCAD plugin that includes WPF control elements. I would like to add a theme to these elements, so I added the WPFThemes.DarkBlend package from Nuget.
To property utilize the theme, you are supposed to add the style reference to your App.xaml file like so:
<Application
...
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Themes\Styles.xaml” />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
Now unfortunately, because this is only a class library, I do not have an App.xaml file in which to add this code. I am able to use my Window.Resources, but in doing so, I am afraid that the styles in the reference are not exposed to the Window element. Is this because the Window is not within the scope of its own resources? Below is an image that shows my current situation:
Thank you!
After creating an x:Key in the style called "DarkWindow", I found that I was able to apply the style directly in the PluginWindow.xaml window properties like this:
<Window Style="{DynamicResource DarkWindow}" />
In my project I am trying to embed source code from Avalon Wizard but there is something strange happening and I am not able to successful integrate it.
I have the following structure in my Custom control library
Wizard
Themes
Aero.NormalColor.xaml
Aero2.NormalColor.xaml
AeroWizardHeader.xaml
Generic.xaml
Wizard97.xaml
WizardAero.xaml
Generic.xaml
Themes
Generic.xaml
Inside my Generic.xaml I have the following delcaration
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="CuratioCMS.Client.UI;Component/Wizard/Themes/Generic.xaml" />
</ResourceDictionary.MergedDictionaries>
and inside Wizard/Themes/Generic.xaml here is how I have my MergedDictionaries defined
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="CuratioCMS.Client.UI;Component/Wizard/Themes/Wizard97.xaml" />
<ResourceDictionary Source="CuratioCMS.Client.UI;Component/Wizard/Themes/WizardAero.xaml" />
<ResourceDictionary Source="CuratioCMS.Client.UI;Component/Wizard/Themes/AeroWizardHeader.xaml" />
</ResourceDictionary.MergedDictionaries>
According to Avalon implementation there is one more MergedDictionary provided inside Aero.NormalColor.xaml which looks like this
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="CuratioCMS.Client.UI;Component/Wizard/Themes/AeroWizardHeader.xaml" />
</ResourceDictionary.MergedDictionaries>
My problem is that I am not able to use my own class library in my project as designer throws exception which is: Cannot locate resource 'wizard/themes/curatiocms.client.ui;component/wizard/themes/wizard97.xaml'.
If I change Path inside Wizard/Theme/Generic.xaml then error goes away but Wizard is not able to provide Aero functionality and even designer does not work ex expected.
Let me also say, that I decided to have this kind of architecture because according to extended WPF toolkit this is very clean way .
can anyone help me with this?
Have you tried using the full pack URI syntax?
Have you tried changing 'Component' to 'component'? Also make sure the dictionary has it's build action set to Resource and you are correctly referencing your CuratioCMS.Client.UI assembly.
For my application themes, I created a separate class library MyApp.Themes.dll.
In the root folder of this library I have Standard.xaml:
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary
Source="pack://application:,,,/MyApp.Themes;component/Standard/Accordion.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
In Standard folder I have Accordion.xaml:
<ResourceDictionary xmlns:layoutPrimitivesToolkit="..."
xmlns:layoutToolkit="..."
...>
<!-- layoutPrimitivesToolkit:AccordionButton -->
<Style TargetType="layoutPrimitivesToolkit:AccordionButton">
...
</Style>
...
</ResourceDictionary>
which are default styles for WPF Toolkit Accordion control, except that style for
AccordionItem is modified to set background to transparent (instead of blue, which is a known bug).
For both xaml files Build Action is set to "Resource".
Now, after referencing MyApp.Themes library in MyApp WPF project, in App.xaml I wrote the following:
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary
Source="pack://application:,,,/MyApp.Themes;component/Standard.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
It doesn't work (no error; just style not applied). If I copy&paste Accordion.xaml styles directly in App.xaml, then it works.
Some people suggested adding dummy resource dictionary, so I added the following in App.xaml after MergedDictionaries ending tag:
<Style TargetType="{x:Type layoutToolkit:AccordionItem}" />
Again, it doesn't work. Can someone help me solve this? By the way, I didn't try an approach
suggested by some others - using basedOn. If I must do that, I'd like to do in MyApp.Themes,
because it makes using themes nicer in App.xaml. Thank you in advance.
UPDATE1: It works if I directly copy&paste Accordion.xaml content to Standard.xaml
UPDATE2: I tried local assembly resource file URI (http://msdn.microsoft.com/en-us/library/aa970069.aspx) in Standard.xaml:
<ResourceDictionary Source="pack://application:,,,/Standard/Accordion.xaml"/>
It throws an error, saying standard/accordion.xaml not found.
It seems there's a bug in .NET. See the thread below:
Trouble referencing a Resource Dictionary that contains a Merged Dictionary
Also, there's a connect page on Microsoft site:
https://connect.microsoft.com/VisualStudio/feedback/details/609601/merge-dictionaries-does-not-work-when-we-merge-merged-dictionaries#tabs
I have Windows Phone App and I want to have a different themed resources based on whether the user has a dark or light theme and which accent color they have chosen.
In my app initialize code I detect the users theme and accent color then load the appropriate Resource Dictionary, Dark, Light etc. I add the Resource Dictionary to the App.Current.Resources.MergedDictionaries collection.
The problem comes when I want to reference a value in the (dynamically loaded) from my App.Xaml. In the below example the key is "DefaultBackgroundImageOpacity". For some reason the values in the ResourceDictionary that I load into the MergedDictionaries collection never get found when the App.Xaml parsing happens. I've played with loading the resources before I call InitializeComponent() and after. Neither seem to resolve the issue.
Any ideas?
// Simplified version of adding some xaml...
// Note I'm loading the key "DefaultBackgroundImageOpacity"
this.Resources.MergedDictionaries.Clear();
var myTestXaml = "<ResourceDictionary xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml' xmlns:System='clr-namespace:System;assembly=mscorlib'> <System:Double x:Key='DefaultBackgroundImageOpacity'>0.2</System:Double></ResourceDictionary>";
this.Resources.MergedDictionaries.Add((ResourceDictionary)XamlReader.Load(myTestXaml));
// This always fails saying that the key "DefaultBackgroundImageOpacity"
// can not be foudnd - even though it was loaded just above
InitializeComponent();
// Phone-specific initialization
InitializePhoneApplication();
I suspect your App.Xaml contains something like this:-
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/somedictionary.xaml" />
...
</ResourceDictionary.MergedDictionaries>
...
</ResourceDictionary>
</Application.Resources>
If that is so then InitializeComponent will replace the default ResourceDictionary which you have manipulated in your code hence your changes to MergeDictionaries will not be present since that instance of a ResourceDictionary is no longer referenced.
If you are not setting up any MergedDictionaries in the App.Xaml then make sure you add resources directly to Applicaiton.Resources and are not creating an new instance of ResourceDictionary in the xaml.
I'm currently working on having dictionaries of styles and templates that I can dynamically apply to my application. Before this "new wanted" dynamical behavior, I had several resource dictionaries, one for each styled control, that I merged in the App.xaml:
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="ColorsDictionary.xaml"/>
<ResourceDictionary Source="ControlsTemplatesDictionary.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
Now, I'd like my application to be styled, so I decided to merge all my previous resources into a new one called "MyFirstTemplates" and to add only this dictionary to the App.xaml.
New dictionary "MyFirstTemplates.xaml":
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">"
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="ColorsDictionary.xaml"/>
<ResourceDictionary Source="ControlsTemplatesDictionary.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
New App.xaml:
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="MyFirstTemplates.xaml"/>
</ResourceDictionary.MergedDictionaries>
<Style TargetType="{x:Type Window}"/>
</ResourceDictionary>
</Application.Resources>
Note: The default style for the Window is to correct a bug of WPF 4, see Adding a Merged Dictionary to a Merged Dictionary
Now that I have made this change, I cannot use a color resource from "ColorsDictionary.xaml" as a StaticResource in "ControlsTemplateDictionary.xaml" anymore. If I change back to merging these files in the app.xaml, everything works. To make it work, I have to change these StaticResource for DynamicResource. Do you have any idea why this doesn't work anymore?
Thank you :-)
By moving the dictionaries out of App.xaml the resources from each dictionary aren't in the other's resource tree during loading of MyFirstTemplates.xaml. Your original setup first loaded ColorsDictionary which was then available through App resources to ControlsTemplatesDictionary while it loaded. In your new setup, in order for the color resource to be available in App resources it needs to be loaded through MyFirstTemplates, which in turn requires loading of both dictionaries, which in turn requires access to the color resource... so it's sort of an infinite loop of references that can't be resolved statically. DynamicResource can wait until everything is loaded and then access the color without issue.
To fix either use Dynamic or merge ColorsDictionary directly into ControlsTemplatesDictionary.
Great answer by John explaining why this is happening.
So the problem is that when using merged dictionaries within a merged dictionary, the inner dictionaries can't "use" each other as StaticResource.
Basic solutions:
Use DynamicResource
Use just a single level of hierarchy from App.xaml when using StaticResource
Both of these solutions have problems. DynamicResource has a performance problem. The 2nd solution limits you on how you organize your XAML resources.
Alternative solution:
I created a small simple program (provided below in GitHub) that will run as a pre-build event and merge XAML files from a folder into one long .XAML file. Well, they need to be with a different extension (.txaml), otherwise they will be compiled.
This allows to structure resources folders and files however you want, without WPF’s limitations. StaticResource and the designer will work always.
The code in GitHub contains a simple solution that contains the merging program. It merges 2 folders into 2 files. One for App.xaml resources and the other for Generic.xaml resources. The .xaml files in a "Controls" project (There's also "Main" project).
Blog post explaining this