Continuing my saga in WPF to WinUI migration (part 1 can be viewed here). Because I’m already using the Community Toolkit for MVVM I’m using some of the other offerings there as well.
I tried, rather than my old approach of using a custom converter, using the ones found in CommunityToolkit.WinUI.Converters. The documentation says that it’s as simple as 1-2-3
- Add the namespace
xmlns:converters="using:CommunityToolkit.WinUI.Converters"
- Add the resource
<Page.Resources>
<converters:StringFormatConverter x:Key="StringFormatConverter"/>
</Page.Resources>
- Call it from your XAML
<TextBlock Text="{x:Bind viewModel.SelectedWorkbook.CountOfWorksheets, Mode=OneWay, Converter={StaticResource StringFormatConverter}, ConverterParameter='{}Count of worksheets: {0}'}"/>
But this fails at build time with an error like follows:
CS1503 Argument 1: cannot convert from 'Company.Dept.App.Views.MainWindow' to 'Microsoft.UI.Xaml.FrameworkElement'
This is a normal C# error like what you’d get when trying to do something assigning a variable of type string to a variable of type integer, but I don’t understand why it manifests itself here when using this converter in exactly the way that the documentation prescribes.
Is there a simple fix for this?
** EDIT **
I noticed the documentation has the namespace hanging off a Page element so I changed it to this, but it didn’t make a whit of a difference.
1
Unlike WPF, in WinUI you can’t use value converters in the Window class XAML.
So, the following code:
<Window
x:Class="WinUIDemoApp.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:local="using:WinUIDemoApp"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Grid x:Name="RootGrid">
<Grid.Resources>
<local:SomeValueConverter x:Key="SomeValueConverter" />
</Grid.Resources>
<Button Content="{x:Bind SomeText, Mode=OneWay, Converter={StaticResource SomeValueConverter}}" />
</Grid>
</Window>
will give you this error:
CS1503 Argument 1: cannot convert from 'WinUIDemoApp.MainWindow' to 'Microsoft.UI.Xaml.FrameworkElement'
There is an open issue in the WinUI GitHub repo about this.
So, I recommend using the Window as a wrapper and placing a Page with your contents in it.
<Window...>
<local:MainPage />
</Window>
3