We Keep Coding

Can't use resources defined in Window.Resources

I have a WPF project with a Window. I've added a style to the resources for that window and I'm trying to use that style on a component, but the resource can't be found!
I believe the syntax is as basic as it can be, and also the same as numerous examples I've seen online:
<Window x:Class="MyView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Window.Resources>
<Style x:Name="ComponentsListItem" TargetType="{x:Type ListViewItem}">
<!-- Some styles -->
</Style>
</Window.Resources>
<Grid>
<ListView ItemContainerStyle="{StaticResource ComponentsListItem}" />
</Grid>
</Window>
When I'm compiling I get an error on {StaticResource ComponentsListItem} that says
The resource "ComponentsListItem" could not be resolved
I have also tried putting the style into a <ResourceDictionary> so that it looks like this:
<Window.Resources>
<ResourceDictionary>
<Style x:Name="ComponentsListItem" TargetType="{x:Type ListViewItem}">
<!-- Some styles -->
</Style>
</ResourceDictionary>
</Window.Resources>
But that gives exactly the same error message on the exact same place.
What is going on here? Why can't I use ComponentsListItem?

Why can't I use ComponentsListItem
That's because you are using x:Name but styles are defined by using x:Key.
Use this and it will work fine
<Style x:Key="ComponentsListItem" TargetType="{x:Type ListViewItem}">
<!-- Some styles -->
</Style>

"Ensure Event Failed" error occur

<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:CustomCalc">
<Style TargetType="{x:Type local:CustomControl1}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:CustomControl1}">
<TextBlock Text="welcome" Height="50" Width="150" MouseDown=""/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
In the above program, (in the program i workout in custom control library)
I am trying to change the control textblock => button.(textblock act as button functionality)
so i try to add a event to the textblock it gives a error message "ensure event failed",
And this file name is "Generic.xaml" so i add a class "Generic.xaml.cs" but same error is show on.
Please explain why it should occur and how to resolve it, thanks in advance.

You need to add a x:Class attribute to support event handlers in the XAML file. So your Generic.xaml should look like this:
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:CustomCalc"
x:Class="CustomCalc.Generic">
<Style TargetType="{x:Type local:CustomControl1}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:CustomControl1}">
<TextBlock Text="welcome" Height="50" Width="150" MouseDown="TextBlock_MouseDown"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
And as for the Generic.xaml.cs :
namespace CustomCalc
{
public partial class Generic : ResourceDictionary
{
private void TextBlock_MouseDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
{
}
}
}
Also don't forget to merge your ResourceDictionary in the App.Xaml file:
<Application.Resources>
<ResourceDictionary >
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="pack://application:,,,/CustomCalc;component/Generic.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>

In my case with Visual Studio 2015 and a WPF project, the error went away after the Visual Studio restart.

In my case the XAML file (App.xaml to be specific) was in a Shared Project at the time I tried to create the event and got stuck for a few minutes with the error subject of this thread.
My solution was to exclude the XAML file along with its XAML.cs file from the Shared Project then linking (not copying !) it in each dependent platform project.
See the following GIF for a graphic visualization of the linking process:
Linking files between projects
Source:
http://geertvanhorrik.com/2015/04/01/fix-for-wpf-images-and-shared-projects/

My issue was resolved by closing and reopening the xaml document causing the error (Visual Studio 2017). My xaml is also in a shared project.
If needed a restart to Visual Studio has helped me also.

Currently running Xamarin Forms in VS 2017 Enterprise and had this issue.
In my case it only occurred when I tried to add an Event Handler to a newly defined xaml Button. Cancelling debugging and trying again fixed this.

Unable to resolve resources using separate files

I feel like this is a common sense and trivial, but i don't understand what i'm doing to begin with. I don't have any other resource I can use for help either. Sometimes i wonder if I'm even googling the question right.
I have some custom styles & templates I've made, but now the file is rather large and difficult to work with. I want to put each style or template in there own XAML files (sorta like headers/implementation files) so that a friend could work on one and then we add it to the project. (Such as Dictionary1.xaml ... ). I started a blank project to keep it simple.
Dictionary1.XAML
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ResourceDictionary x:Key="SomeKey">
<Color x:Key="detailMark">Black</Color>
<SolidColorBrush x:Key="detailMarkBrush" Color="{StaticResource ResourceKey=detailMark}" />
<Style x:Key="flatTextBox" TargetType="{x:Type TextBox}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TextBox}">
<Grid>
<Rectangle Stroke="{StaticResource ResourceKey=detailMarkBrush}" StrokeThickness="1"/>
<TextBox Margin="1" Text="{TemplateBinding Text}" BorderThickness="0"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
App.XAML
<Application x:Class="WpfApplication1.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication1"
StartupUri="MainWindow.xaml">
<Application.Resources>
<local:MainWindow x:Key="SomeKey"/>
</Application.Resources>
</Application>
And MainWindow.XAML
<Window x:Class="WpfApplication1.MainWindow"
xmlns:local="clr-namespace:WpfApplication1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow"
Height="350" Width="525">
<Grid>
<TextBox Style="{DynamicResource flatTextBox}"> <!-- doesn't autocomplete/work -->
</TextBox>
</Grid>
</Window>
Edit:
<TextBox Style="{Binding Mode=OneWay, Source={StaticResource SomeKey}}">
<!-- Throws System.Windows.Markup.XamlParseException -->
</TextBox>

As Alex mentioned, the right way to do this is using Merged Dictionaries.
Therefore, you should structure your project correctly, otherwise it will end up in a mess.
Keeping your "blank project", it should look like this:
YourProject
App.xaml (.cs)
MainWindow.xaml (.cs)
SomeOtherWindow.xaml (.cs)
Resources folder
Dictionary1.xaml
Dictionary2.xaml
...
Then you have to decide:
Do you want the resources to be available application wide?
Or do you want the resources to vary between certain windows / user controls?
If you want #1, you have to merge the dictionaries in the App.xaml file:
<Application x:Class=...
...>
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Resources/Dictionary1.xaml"/>
<ResourceDictionary Source="Resources/Dictionary2.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
</Application>
If you want #2, you have to merge the dictionaries in the specific window / user control file:
<Window x:Class=...
...>
<Window.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Resources/Dictionary1.xaml"/>
<ResourceDictionary>
<!-- Window specific resources -->
</ResourceDictionary>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Window.Resources>
<!-- Content -->
</Window>

external xaml resource not found by designer when referenced from control template

I have external library libccc with its own resources defined like this:
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ccc="clr-namespace:libccc"
>
<ccc:BooleanToHiddenVisibilityConverter x:Key="BooleanToHiddenVisibilityConverter" />
</ResourceDictionary>
In my main project I include it using ResourceDictionary.MergedDictionaries in main app.xaml:
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="pack://application:,,,/libccc;component/Resources/Converters.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
Now my problem is that when I reference that resource from Control template only like this:
<window style="{StaticResource MyDialog}">
</window>
where style is defined in application like this:
<ResourceDictionary>
<Style x:Key="MyDialog" TargetType="{x:Type Window}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Window}">
<Grid>
<Label HorizontalAlignment="Center" Content="{Binding UpdateResultDescription}" Visibility="{Binding UpdateEnded, Converter={StaticResource BooleanToHiddenVisibilityConverter}, FallbackValue=Hidden}" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary
VisualStudio Designer throws exception:
Exception: Cannot find resource named 'BooleanToHiddenVisibilityConverter'. Resource names are case sensitive.
My application works as expected, but designer throws exception. When I reference my libccc in other windows that do not use control template then designer works fine.
Anyone can give me a hint what can I change to make designer work?

Load control style from separate file in wpf

I have the following style added to my Windows.Resources
<Window.Resources>
...
<!--A Style that extends the previous TextBlock Style-->
<!--This is a "named style" with an x:Key of TitleText-->
<Style BasedOn="{StaticResource {x:Type TextBlock}}"
TargetType="TextBlock"
x:Key="TitleText">
<Setter Property="FontSize" Value="26"/>
<Setter Property="Foreground">
<Setter.Value>
<LinearGradientBrush StartPoint="0.5,0" EndPoint="0.5,1">
<LinearGradientBrush.GradientStops>
<GradientStop Offset="0.0" Color="#90DDDD" />
<GradientStop Offset="1.0" Color="#5BFFFF" />
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>
</Setter.Value>
</Setter>
</Style>
...
</Window.Resources>
I have a lot of those styles in my xaml code and I would like to save each component style to an extra file (not an external file).. for example all the styles related to TextBlocks should be in a file called TextBlockStyles.xaml
How would I do this in wpf?
How do I link the style in my project ?
Thanks in advance

You use merged resource dictionaries
In you app.xaml you would use
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary
Source="/Your.Assembly.Name;component/TextBlockStyles.xaml"/>
... other dictionaries here
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
or directly into a UserControl would be
<UserControl.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary
Source="/Your.Assembly.Name;component/TextBlockStyles.xaml"/>
... other dictionaries here
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</UserControl.Resources>
You can shorten Source="..." to just Source="TextBlockStyles.xaml" if the file is in the same assembly and in the root of the project, or alternatively Source="Styles\TextBlockStyles.xaml" if you put the resource dictionary into the folder Styles.

Use case: you have a user control called MyView.xaml with a button. You want to style the button with an external XAML file.
In MyView.xaml:
<User Control ...namespaces...>
<UserControl.Resources>
<ResourceDictionary>
...converters...
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="MyButton.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</UserControl.Resources>
...the rest of the control...
</UserControl>
In MyButton.xaml:
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:MSDNSample">
<Style x:Key="FooButton" TargetType="{x:Type Button}">
<Setter Property="Background" Value="Pink" />
</Style>
</ResourceDictionary>
Back to MyView.xaml ("the rest of the control"):
<Button Style="{StaticResource FooButton}">
Hello World
</Button>

In Solution Explorer Right Click on your Project Select Add After that click on Resource Dictionary...
Choose name and add to your project.
Open App.xaml
Add This Code in Application Tag
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="YourStyle.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
In YourStyle.xaml :
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:APPNAME">
<Style x:Key="ButtonStyle" TargetType="{x:Type Button}">
<Setter Property="Background" Value="Pink" />
</Style>
</ResourceDictionary>

you are looking for the dynamic resources. well the best way is to load and marge the dictionary in the resources. application or either on control page.
here is a good sample for it.
http://blogs.msdn.com/b/wpfsdk/archive/2007/06/08/defining-and-using-shared-resources-in-a-custom-control-library.aspx
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Dictionary1.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
this.Resources.MergedDictionaries.Add(Smyresourcedictionary);

Simply, go to your Window (example: MaindWindow.xaml) where you want to include the resource from the outer file and use MergedDictionaries principle to refer to that file:
<Window x:Class="UseMergedResource.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Title="MainWindow"
Height="600"
Width="600">
<Window.Resources>
<!-- DECLARING MERGED DICTIONARY -->
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source='Merged/BrushResources.xaml' />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
<!---------------------------------->
</Window.Resources>
<StackPanel>
<Rectangle Width='200'
Height='100'
Fill='{StaticResource PrimaryBrush}' /> <!-- USAGE HERE -->
</StackPanel>
</Window>
From above Merged/BrushResources.xaml is the location of the resource file, which is located under the folder called Merged.
Now if you are wondering what should be the declaration syntax in the outer file, check this:
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<!-- Location for application brushes -->
<SolidColorBrush x:Key='BorderBrush'
Color='Orange' />
<SolidColorBrush x:Key='HighLightBrush'
Color='LightBlue' />
<SolidColorBrush x:Key='PrimaryBrush'
Color='Pink' />
<SolidColorBrush x:Key='AccentBrush'
Color='Yellow' />
</ResourceDictionary>
If you want to make the resource available through all application (visible in all your windows) then declare in the App.xaml resources section.