TimberStalker Posts - Answer Overflow

TimberStalker

•Created by TimberStalker on 6/4/2024 in #help

WinUI: Creating a DataTemplate through Code doesent resolve all bindings.

I have a binding attachment that lets me add items to a MenuBarItem dynamically. It adds an ItemSource and ItemTemplate.

<MenuFlyoutSubItem Text="{Binding Name}" ctrl:BindableMenuBarItem.ItemsSource="{Binding Operations}" ctrl:PrintAttachment.Print="{Binding Operations}">
    <ctrl:BindableMenuBarItem.ItemTemplate>
        <DataTemplate>
            <MenuFlyoutItem Text="{Binding Name}" CommandParameter="{Binding}" Command="{Binding AddOperationCommand,ElementName=vm}"/>
        </DataTemplate>
    </ctrl:BindableMenuBarItem.ItemTemplate>
</MenuFlyoutSubItem>

<MenuFlyoutSubItem Text="{Binding Name}" ctrl:BindableMenuBarItem.ItemsSource="{Binding Operations}" ctrl:PrintAttachment.Print="{Binding Operations}">
    <ctrl:BindableMenuBarItem.ItemTemplate>
        <DataTemplate>
            <MenuFlyoutItem Text="{Binding Name}" CommandParameter="{Binding}" Command="{Binding AddOperationCommand,ElementName=vm}"/>
        </DataTemplate>
    </ctrl:BindableMenuBarItem.ItemTemplate>
</MenuFlyoutSubItem>

The Name and CommandParameter bindings both get set, but the command binding doesent run at all, presumably due to the ElementName. I even created a special print attachment property and if I had ElementName, it didnt print anything, but it did correctly print the other things. This might be because i have to create the DataTemplates in the code behind that it doesent let things with relative bindings get set. This is what I do.

    static async void BuildArguments(MenuFlyoutSubItem m, IEnumerable source, DataTemplate template)
    {
        try
        {
            Action h = () =>
            {
                m.Items.Clear();
                foreach (var item in source)
                {
                    var content = (MenuFlyoutItemBase)template.LoadContent();
                    content.DataContext = item;
                    m.Items.Add(content);
                }
            };
            await m.DispatcherQueue.EnqueueAsync(h, DispatcherQueuePriority.Normal);
        }
        catch (Exception ex)
        {
            Debug.WriteLine($"error creating menu bar sub items: '{ex.Message}'");
        }
    }

    static async void BuildArguments(MenuFlyoutSubItem m, IEnumerable source, DataTemplate template)
    {
        try
        {
            Action h = () =>
            {
                m.Items.Clear();
                foreach (var item in source)
                {
                    var content = (MenuFlyoutItemBase)template.LoadContent();
                    content.DataContext = item;
                    m.Items.Add(content);
                }
            };
            await m.DispatcherQueue.EnqueueAsync(h, DispatcherQueuePriority.Normal);
        }
        catch (Exception ex)
        {
            Debug.WriteLine($"error creating menu bar sub items: '{ex.Message}'");
        }
    }

Is my problem the way I create the child contents, and if so what can I do to fix it.

1 replies

CC#

•Created by TimberStalker on 5/3/2023 in #help

❔ Fire and forget

Is there a recommended way to call an async void, or to run an async task as fire and forget? I havent been able to find any that doesent cause a warning, and i would rather not supress it.

10 replies

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