No equivalent of WPF's IsItemsHost ?

[cboittin]

When creating an ItemsControl, WPF allows to give its ItemsPanel a full XAML structure and define where to put the elements by setting the IsItemsHost property on any Panel of that structure.
In Avalonia, that property exists but cannot be set by the user, and i don't know if it's even used. It automatically uses the first Panel set in the ItemsPanelTemplate.

It's not critical, since we can instead redefine the ControlTemplate of the ItemsControl (and that one is pretty simple), but that requires knowing the template and some copy-pasting. In WPF, we can just define the part we're trying to customize.

So, this would work in WPF-style, but in Avalonia it adds the items as children of Grid:

<Style Selector="ItemsControl">
  <Setter Property="ItemsPanel">
    <ItemsPanelTemplate>
      <Grid>
        <Grid.ColumnDefinitions>
          <ColumnDefinition Width="*" MaxWidth="600"/>
        </Grid.ColumnDefinitions>
        
        <StackPanel IsItemsHost="True"/>
      </Grid>
    </ItemsPanelTemplate>
  </Setter>
</Style>

In Avalonia, we have to redo the entire template:

<Style Selector="ItemsControl">
  <Setter Property="Template">
    <ControlTemplate>
      <Border Background="{TemplateBinding Background}"
              BorderBrush="{TemplateBinding BorderBrush}"
              BorderThickness="{TemplateBinding BorderThickness}"
              CornerRadius="{TemplateBinding CornerRadius}"
              Padding="{TemplateBinding Padding}">
        <Grid>
          <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" MaxWidth="600"/>
          </Grid.ColumnDefinitions>
          <ItemsPresenter Name="PART_ItemsPresenter" ItemsPanel="{TemplateBinding ItemsPanel}"/>
        </Grid>
      </Border>
    </ControlTemplate>
  </Setter>
</Style>

I couldn't find mention to this in the differences with WPF. Any plan to implement it at some point ? It could be interesting to know how Avalonia XPF handles that.
I also found this SO comment which explains in detail how it works in WPF.

[rabbitism]

It is internal property in avalonia