Inside a XAML Page I'm trying to use an IValueConverter, it's throwing an error.
The IValueConverter is in another assembly, I have added a reference
There are no design-time errors
I have assigned the StaticResource with a ResourceKey
At the top of my page I have this:
xmlns:converters="clr-namespace:Converters;assembly=Converters"
<Page.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Styles/DialogStyles.xaml" />
</ResourceDictionary.MergedDictionaries>
<converters:NoWhiteSpaceConverter x:Key="NoWhiteSpaceConverter" />
</ResourceDictionary>
</Page.Resources>
Then I try to use it later on like this:
<TextBox Text="{Binding SomeText, Converter={StaticResource NoWhiteSpaceConverter}}" />
Can anyone see what the problem is?
Make sure that the resources are defined before the usage (in Xaml parsing order). The easiest way is to place it into App.xaml
See also here for a similar issue: https://paulkiddie.com/the-importance-of-the-position-of-window-resources-element-in-wpf-xaml-markup/
In my case the resource was correctly defined before it is used but there was a wrong reference to a converter.
The problematic line was
...{Binding MyProperty, Converter={StaticResource local:MyConverter}}
and it should be without the namespace alias
...{Binding MyProperty, Converter={StaticResource MyConverter}}
where local is a namespace alias containig the converter class and MyConverter is the key defined in a resource in the XAML.
Related
Is there a way to reference a local ResourceDictionary from within the same FrameworkElement's property?
I tried the following
<TextBlock Text="{StaticResource txt}">
<TextBlock.Resources>
<x:String x:Key="txt">asdf</x:String>
</TextBlock.Resources>
</TextBlock>
but get the error
The resource "txt" could not be resolved.
Moving the txt resource from the TextBlock to the Page resources would work but that seems messy and i was hoping that it's possible to reference a FrameworkElements local ResourceDictionary.
Using CustomResource instead of StaticResource at least allows to auto complete to txt, but it doesn't work because then invoking Initializecomponent throws an exception: "No custom resource loader set" and i'm not sure if implementing and setting a custom loader would solve that at all.
Is there a way to do this using the local resource dictionary?
UWP FrameworkElement resource lookup looks for parent control resources, not child control resources.
This document details how Resources works.
Edit
It is recommended to use Resource Dictionary file.
Right click on your project
Choose Add
Choose Resource Dictionary.
You can put your all your resource in this file.
Then add a resource file reference in App.xaml.
Dictionary1.xaml
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Style x:Key="txt" TargetType="TextBlock">
<Setter Property="Text" Value="asdf"/>
</Style>
</ResourceDictionary>
App.xaml
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Dictionary1.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
Page.xaml
<TextBlock Style="{StaticResource txt}" ></TextBlock>
I have a grid that I am trying to hook up a visibility converter to. I have a class set up in the HelperObjects namespace, but for some reason the xaml is not picking up the reference. The error message is "The resource BoolToVisConverter could not be resolved" Why won't the xaml pull in this resource? I am sure I am doing something ridiculous here...
Here is the xaml:
xmlns:HelperObjects="clr-namespace:foo.HelperObjects"
...
<Grid Visibility="{Binding isZoneTwoVisible, Converter={StaticResource BoolToVisConverter}}">
The error message is indicating that the resource identified by the key BoolToVisConverter, to which you're trying to bind, cannot be found.
The most likely explanation is that you haven't declared that resource within a scope that can be accessed by your xaml. You'll want to create a StaticResource with a key matching the name you're referencing, within a Resources section of your xaml, the exact location may vary depending on your needs/structure.
Assuming you're doing this within a Window, you could do something like:
<Window>
<Window.Resources>
<BooleanToVisibilityConverter x:Key="BoolToVis"/>
</Window.Resources>
<Grid Visibility="{Binding isZoneTwoVisible, Converter={StaticResource BoolToVis}}">
<--...Content...-->
</Grid>
</Window>
Note: I haven't included your namespace in front of the BooleanToVisibilityConverter because this is a class which already exists within the framework.
It may be the case you require slightly different behaviour, or don't have access to that class, in which case you may need to add your namespace when defining the resource, e.g. <HelperObjects:BooleanToVisibilityConverter x:Key="BoolToVis"/>
Potentially useful further info about static resources: https://learn.microsoft.com/en-us/dotnet/framework/wpf/advanced/staticresource-markup-extension
Try to specify the converter in UserControlResources or even parent level Grid Resources. Assuming you are using a UserControl.
And your code is unclear as of where you are defining the StaticResource BoolToVisConverter. But generally heres the process.
Look at this sample code below to define your StaticResorce in the UserControl Resources section. Make sure you set the DataContext where isZoneTwoVisible is residing. I am hoping you implemented ImplementINotifyPropertyChanged and said PropertyChanged on your isZoneTwoVisible or isZoneTwoVisible is a DependencyProperty. Note: BooleanToVisibilityConverter is a class that implements an IValueConverter or if your property is a bool you don't even need that class.
<UserControl.Resources>
<BooleanToVisibilityConverter
x:Key="boolToVisibility"></BooleanToVisibilityConverter>
</UserControl.Resources>
You did all the things said above and it still dosen't work, sometimes I specify the relative Source hoping its residing in a UserControl.
Visibility="{Binding isZoneTwoVisible,Converter={StaticResource boolToVisibility},RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=UserControl}}">
I'm having trouble resolving a component resource key in my WPF app for a DLL I was trying to use.
DLL source I'm trying to use:
https://www.codeproject.com/Articles/42227/Automatic-WPF-Toolkit-DataGrid-Filtering
Error message:
The resource "{ComponentResourceKey ResourceId=DataGridHeaderFilterControlStyle, TypeInTargetAssembly={x:Type ScoreBoardClientTest:DataGridHeaderFilterControl}}" could not be resolved.
I've compiled the DLL and added it as a reference to my project.
I've added the appropriate xmlns filter to my XAML see below:
xmlns:filter="clr-namespace:DataGridFilterLibrary;assembly=DataGridFilterLibrary"
When I try to use a columnheaderstyle in my data grid is when the error above is thrown
ColumnHeaderStyle="{StaticResource {ComponentResourceKey
TypeInTargetAssembly={x:Type filter:DataGridHeaderFilterControl},
ResourceId=DataGridHeaderFilterControlStyle}}"
any help determining what I'm doing wrong here would be great. Thought it was straight forward.
I run into the same problem, when I using the filter in a UserControl. In a Window it works as expected.
Fixed this problem with adding the Ressource in the UserControl:
<UserControl.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="pack://application:,,,/DataGridFilterLibrary;component/Themes/Generic.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</UserControl.Resources>
I have a binding to a parent-element. How can I provide the data type for the DataContext in the binding, so intellisense can resolve the bound Properties?
The binding works fine at runtime. So, I have the following XAML structure:
<TabControl Name="TabDynamic"
ItemsSource="{Binding TabItems, Mode=OneWay}" ...>
<TabControl.Resources>
<DataTemplate x:Key="TabHeader" DataType="TabItem">
<DockPanel>
<TextBlock Text="{Binding RelativeSource={RelativeSource AncestorType={x:Type TabItem}}, Path=Header}" />
<Button Command="{Binding ElementName=TabDynamic, Path=DataContext.DeleteTabCommand}"
CommandParameter="{Binding ElementName=TabDynamic, Path=DataContext.TabItems/}">
<Image Source="{DynamicResource DeleteImg}" Height="11" Width="11"></Image>
</Button>
</DockPanel>
</DataTemplate>
<DataTemplate x:Key="TabContent" DataType="viewModels:ConnectionInfoVM">
<views:BufferViewerControl/>
</DataTemplate>
</TabControl.Resources>
</TabControl>
The data type of the DataContext is "viewModels:ConnectionInfoVM".
Intellisense will now underline both Properties on the DataContext (so DeleteTabCommand and TabItems are underlined).
I already tried to use the design-time data-context definition "d:DataContext" within the Button element like so:
d:DataContext="{d:DesignInstance viewModels:ConnectionInfosVM}"
But this does not change the intellisense warnings.
I also tried to define the DataType on the DataTemplate to be "viewModels:ConnectionInfosVM", as I do for the content-template, but that too does not change the intellisense warnings (and I guess would be wrong, as the data type of the element really is a TabItem).
Another try was to define the DataContext by adding the following to the Button element definition:
<Button.DataContext>
<viewModels:ConnectionInfosVM/>
</Button.DataContext>
But this too, does not get rid of the warnings.
I found a solution at least for the above described problem. I was setting the DataContext of the window in question in the code-behind. The TabControl in my example just inherits that DataContext, which is a ConnectionInfosVM.
In order to fix those warnings (and of course for the gained flexibility in providing a DataContext by a Locator), I defined the DataContext in XAML like so:
<UserControl ...
DataContext="{Binding Source={StaticResource mainViewModelLocator}, Path=ConnectionInfosVM}">
It seems that intellisense is now able to resolve those references. But on the other side, I also changed the TextBlock contained within the DataTemplate to the following:
<TextBlock Text="{Binding RelativeSource={RelativeSource AncestorType={x:Type TabItem}}, Path=DataContext.Address}" />
Now the DataContext of such a TabItem is actually a different type, as it is the type of the backing object for the TabItem. So in this case, the Property Address cannot be found by intellisense.
So, the question kind of remains, is there a possibility to define the type of the DataContext within a binding defined in a DataTemplate?
I needed to add the mc:Ignorable="d" attribute to the Window tag. Essentially I learned something new. The d: namespace prefix that Expression Blend/Visual Studio designer acknowledges is actually ignored/"commented out" by the real compiler/xaml parser!
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
The following was taken from
Nathan, Adam (2010-06-04). WPF 4 Unleashed (Kindle Locations 1799-1811). Sams. Kindle Edition.
Markup Compatibility
The markup compatibility XML namespace (http://schemas.openxmlformats.org/markup-compatibility/2006, typically used with an mc prefix) contains an Ignorable attribute that instructs XAML processors to ignore all elements/attributes in specified namespaces if they can’t be resolved to their .NET types/members. (The namespace also has a ProcessContent attribute that overrides Ignorable for specific types inside the ignored namespaces.)
Expression Blend takes advantage of this feature to do things like add design-time properties to XAML content that can be ignored at runtime.
mc:Ignorable can be given a space-delimited list of namespaces, and mc:ProcessContent can be given a space-delimited list of elements. When XamlXmlReader encounters ignorable content that can’t be resolved, it doesn’t report any nodes for it. If the ignorable content can be resolved, it will be reported normally. So consumers don’t need to do anything special to handle markup compatibility correctly.
I am a beginner of MVVM. I wanted to bind selected treeview item to a textblock. I found a solution here. So I implemented the same in my project...:
<TextBox Text="{Binding SelectedItem, Converter={StaticResource GetTextFromItemConverter}, ElementName=tvMain, Mode=OneWay}"
Also created the GetTextFromItemConverter class in my viewmodel(same as in the solution).
But in xaml I got error saying
The resource GetTextFromItemConverter could not be resolved.
How to resolve this issue??
I suppose the class GetTextFromItemConverter is defined in some namespace called TestDemo. You first have to create some instance of that class as some resource in XAML. As an example, you can add it as some resource of Window.Resources, we need to import the namespace of that class so that we can create an instance of that class, something like this:
<Window ...
xmlns:local="clr-namespace:TestDemo">
<Window.Resources>
<local:GetTextFromItemConverter x:Key="textConverter"/>
</Window.Resources>
<!-- ... -->
<TextBox Text="{Binding SelectedItem,
Converter={StaticResource textConverter},
ElementName=tvMain, Mode=OneWay}"/>
<!-- ... -->
</Window>
Note about the added part xmlns:local="clr-namespace:TestDemo" is to import the TestDemo namespace and aliased as local prefix. The ... is a placeholder for what you have in your Window (auto-generated by designer).
Check whether the view model that you have mapped is properly referenced, if so its perfect check for the path reference to the converter that you have used.
For example:
xmlns:converter="using your namespace path"-location where the converter is placed in the resource dictionary.