How to add converter in codebehind

Question

How do you programatically in code behind use a converter on the display member path or use a itemtemplate with the converter?

     var listView = new ListView
         {
             ItemsSource = SomeObject,
             HorizontalAlignment = HorizontalAlignment.Right,
             SelectionMode=ListViewSelectionMode.Single,
             DisplayMemberPath=<---use converter here
         };
         var stackPanel = new StackPanel();
         stackPanel.Children.Add(listView);

Equivalent xaml example for reference:

    <ListView ItemsSource="{x:Bind Object, Mode=OneWay}">
                  <ListView.ItemTemplate>
                      <DataTemplate>
                          <TextBlock Text="{Binding Converter={StaticResource Converter}}"/>
                      </DataTemplate>
                  </ListView.ItemTemplate>
                </ListView>

Answer 1

You can create an ItemTemplate in code-behind using the XamlReader. This should be the closest thing to your XAML.

string xamlString =
    """
    <DataTemplate
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="using:WinUIDemoApp">
        <Grid>
            <Grid.Resources>
                <local:Converter x:Key="Converter" />
            </Grid.Resources>
            <TextBlock Text="{Binding Name, Converter={StaticResource Converter}}" />
        </Grid>
    </DataTemplate>
    """;

var listView = new ListView();
listView.ItemTemplate = XamlReader.Load(xamlString) as DataTemplate;

Just make sure to replace using:WinUIDemoApp with the correct namespace for your converter.

If you want to dynamically set the converter's namespace, you can:

string converterNamespace = typeof(Converter).Namespace;
string xamlString =
$$$"""
<DataTemplate
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:{{{converterNamespace}}}">
    <Grid>
        <Grid.Resources>
            <local:Converter x:Key="Converter" />
        </Grid.Resources>
        <TextBlock Text="{Binding Name, Converter={StaticResource Converter}}" />
    </Grid>
</DataTemplate>
""";

and this is a known issue but you also need to explicitly declare? the converter in XAML so the converter gets registered as resources. One of the following to be specific:

A. On your page

<Page.Resources>
    <local:Converter x:Key="Converter" />
</Page.Resources>

B. On App.xaml

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" />
            <!--  Other merged dictionaries here  -->
        </ResourceDictionary.MergedDictionaries>
        <!--  Other app resources here  -->
        <local:Converter x:Key="Converter" />
    </ResourceDictionary>
</Application.Resources>

C. On a ResourceDictionary

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:WinUIDemoApp">

    <local:Converter x:Key="Converter" />

</ResourceDictionary>