WPF Call an animation in ViewModel - c#

I have made an animation in a xaml.cs file:
((Storyboard)FindResource("animate")).Begin(CurrentMatchLBLProgress);
But if I copy this and take it to the ViewModel, I get an error:
The name 'FindResource' does not exist in the current context.
How do I make this line of code work from the ViewModel?

You can access resources like below,
<Application
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
StartupUri="MainWindow.xaml"
>
<Application.Resources>
<Image x:Key="ApplicationResource" Source="ApplicationResource.bmp" />
</Application.Resources>
</Application>
object resource = Application.Current.TryFindResource("ApplicationResource");

Related

WinUI 3 "XAML parsing failed." when adding MenuBar

I'm experimenting with WinUI 3 and trying to create a basic user interface.
As soon as I add a MenuBar control, I get a Microsoft.UI.Xaml.Markup.XamlParseException: 'XAML parsing failed.' at the InitializeComponent() line of that view's code-behind when trying to start the app.
I can add other controls without issues, but MenuBar always seems to break the app. What am I missing?
Check your App.xaml to include the <XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" /> resource dictionary like this:
<Application
x:Class="Your.Project.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<!-- the following line is important -->
<XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
</Application>

VisualStudios ERROR MainViewModel doesnt exist

Hy Guys i installed VS three times and everytime the same Error
I installed MVVM Light in the NUGET Manager for the MVVM
After installing i set the DataContext in the Main.Window on MainViewModel
That works now. But in my App.xaml is it not possible to get the Resource Dictonary in it. In attachment screenshots of my problem.
appxaml ( <= Full size image)
and...
Try to declare 'vm' namespace before usage, put it in Application tag.
Replace <vm: with <local: as the "local" namespace is aleady mapped at the root element in App.xaml:
<Application x:Class="testapp.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:testapp.ViewModel"
StartupUri="MainWindow.xaml">
<Application.Resources>
<local:ViewModelLocator x:Key="Locator" />
</Application.Resources>
</Application>

Using (merged) Resource Dictionary in C# Class Library Project

How can I use a (merged) WPF Resource Dictionary in a C# class library project?
Here is what I did:
In my C# class library project I have a file Dictionary1.xaml like that:
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
>
<Style x:Key="PluginFrameBorderStyle">
...
</Style>
</ResourceDictionary>
Then, I have a UserControl file UserControl1.xaml where I try to use the Dictionary like that:
<UserControl x:Class="EditorPackageA.BackboneMemberB1Editor.BackboneMemberB1Editor"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
xmlns:local="clr-namespace:EditorPackageA.EditorBase"
xmlns:prism="http://www.codeplex.com/prism" d:DesignWidth="690.4" d:DesignHeight="460.12">
<UserControl.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/Dictionary1.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</UserControl.Resources>
...
</UserControl>
The project compiles but at runtime I get the error:
with the exception detail:
The same approach works when applied within a WPF project rather than a Class Library project.
What might be the solution here?
Important Addendum:
During design-time I see the effect of the used style that is embedded via the ResourceDictionary, hence the URI of the style and the dictionary must be correct!?
Try to use so called pack URI. I think that you have to explicitly specify where the resource dictionary is located.
<ResourceDictionary Source="pack://application:,,,/TheNameOfClassLibrary;component/Dictionary1.xaml"/>
In the case of a WPF project your approach works because WPF engine by default looks for resource in the assembly being executed (in exe).
You should refer/link the ResourceDictionary xml file to the Source attribute with assembly and component name.
Use relative path as follows:
<ResourceDictionary Source="../Dictionary1.xaml" />
If it is not working, then try PACK URL
<ResourceDictionary Source="pack://application:,,,/Your.Base.AssemblyName;component/DictionaryFolder/Dictionary1.xaml" />
Hope it helps you
You probably need to merge your library's resource dictionary in your application resources. You need to edit your App.xaml file and add something like:
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="pack://application:,,,/YourAssembly;component/Dictionary1.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>

ResourceReferenceKeyNotFoundException declared on Dictionary.xaml

I have an ObjectDataProvider declared on a dictionary:
<ObjectDataProvider x:Key="Resources"
ObjectType="{x:Type const:CultureResources}"
MethodName="GetResourceInstance"/>
And I have a class that wants to find it like this:
m_provider = (ObjectDataProvider) App.Current.FindResource("Resources");
But when it tries to find the Resource, it launches the error
ResourceReferenceKeyNotFoundException
And can't find my resource... Here you have an image on how my project is divided:
The Default.xaml is my default dictionary.
So, why I can't find my Resources element defined on my dictionary?
I need to answer my question, because it was such a weird thing...
At first, I need to say that I had to add my Dictionary.xaml to my App.xaml:
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="../themes/Default.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
For some reason, it wasn't enough to call it on my MainWindow.xaml. So I erased it from my MainWindow.xaml and added it to App.xaml, but I couldn't have them inserted in both sides. That was the part that I couldn't see clearly...

wpf image resources and changing image in wpf control at runtime

I would like to know exactly how to dynamically use a Dictionary Resource in the C# code behind - ie.. I would like to load images at runtime from an image resource within a dictionary
I have a program that has 3 images in a WPF Dictionary - these are images set as image resources.
Then in the code behind of my WPF Window I want to load any one of the three images based on user initiated events.
There is no real code I have to show as nothing that I have done works.
Ideas?
First, make sure you've defined your image resources like this:
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ImageSource x:Key="image1">images/image1.jpg</ImageSource>
<ImageSource x:Key="image2">images/image2.jpg</ImageSource>
</ResourceDictionary>
Secondly, I'm assuming that your WPF dictionary is in its own file. Now you have to make sure you've merged your dictionary into your main window's XAML (skip this step if your resource dictionary is defined inside of the window's XAML). In your window's XAML file, make sure you have something like this:
<Window.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="myDictionary.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Window.Resources>
Now, in your code-behind, you can use the FindResource() method to locate your image resource by it's key name (the value of the x:Key attribute on the ImageSource in the resource dictionary) like so:
imageControl.Source = (ImageSource)FindResource("image1");
Hope this helps!
This is an addition to the accepted answer:
When working within a ViewModel from MVVM, make sure to use the FindResource from the view where the resource directory is added.
<Window x:Class="My.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ViewModels="clr-namespace:My.ViewModels"
Title="USA Hockey Player Evaluation tool"
Icon="/USAHockeyPlayerEval;component/View/Images/HET.ico"
SizeToContent="WidthAndHeight"
MinHeight="500px" MinWidth="800px">
<Window.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Images.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Window.Resources>
<Window.DataContext>
<ViewModels:MainWindowMV/>
</Window.DataContext>
<StackPanel>
<Menu>
<MenuItem Header="File">
<MenuItem Header="Save"></MenuItem>
My view in this case is a window (I know not correct MVVM ;-) )
Image img = new Image();
img.Source = (ImageSource)WindowReference.FindResource("Pluse");
Here the WindowReference is a reference to My.MainWindow.

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