DannyRoastBeef㊙ Posts - Answer Overflow

DannyRoastBeef㊙

•Created by DannyRoastBeef㊙ on 4/10/2024 in #help

(Blazor) I'm having trouble accessing a variable inside a parent component.

I'm trying to access a simple bool in a parent component that shows when my side bar has been collapsed. I'm using the Blazor Fluent UI components by the way. Okay so I've got this FluentNavMenu:

<FluentNavMenu Id="main-menu" Collapsible="true" Width="250" Title="Navigation menu" @bind-Expanded="SideBarExpanded">
...
</FluentNavMenu>

@code {

    [Parameter]
    public bool SideBarExpanded {get; set;}= true;
}

<FluentNavMenu Id="main-menu" Collapsible="true" Width="250" Title="Navigation menu" @bind-Expanded="SideBarExpanded">
...
</FluentNavMenu>

@code {

    [Parameter]
    public bool SideBarExpanded {get; set;}= true;
}

Then I've got a parent component:

<FluentStack>
...
<NavMenu  (I've tried different bindings here but nothing has worked)/>
...
</FluentStack>

<FluentStack>
...
<NavMenu  (I've tried different bindings here but nothing has worked)/>
...
</FluentStack>

That binding sets the SideBarExpanded every time I open or close it. I need to access it in a parent component to hide something else. What's the best way to detect that this variable has changed in the parent? There is also a component attribute I can add to the FluentNavMenu called ExpandedChanged which takes in an EventCallback, but I have no idea how to use it in the context of this particular component. I've watched this video around 10 times and I still can't wrap my head around it as this particular scenario seems different. Thanks!

4 replies

CC#

•Created by DannyRoastBeef㊙ on 4/3/2024 in #help

Using ref for large data types.

Hi, just looking for a little clarification on the ref keyword when passing data into a function. I've hot an API endpoint which takes in files which passes them though to a function which checks them and sorts them into an appropriate destination directory. I've got a function in another class which checks the data type is supported, among other things. Would I be right to pass the incoming multipart File data to it using a ref value to avoid making a copy of it? Some of the files can run up to 200mb in size. Thanks for any help.

10 replies

CC#

•Created by DannyRoastBeef㊙ on 7/9/2023 in #help

❔ How do I get event arguments and other data into my view model when using MVVM?

I'm using the Command interface in my XAML code on a TapGestureRecognizer ->

Command="{Binding Source={RelativeSource AncestorType={x:Type viewmodel:CataloguePageViewModel}},Path=TappedCommand}"

Command="{Binding Source={RelativeSource AncestorType={x:Type viewmodel:CataloguePageViewModel}},Path=TappedCommand}"

I'm binding it to a method in my view model which allows me to change page when I select an item from a CollectionView ->

async Task Tapped(object obj)
        {
            await Shell.Current.GoToAsync(nameof(Views.CatalogueDetails));
        }

async Task Tapped(object obj)
        {
            await Shell.Current.GoToAsync(nameof(Views.CatalogueDetails));
        }

I know i can use a query parameter in the URL to pass that through to the new page but how do I send my currently selected item from the CollectionView in the View xaml to my View Model so I can populate the following details page with the correct information? My current assumption is that I bind to SelectedItem in the collection view in the view xaml but I'm not sure if this is the best approach. Thanks!

8 replies

CC#

•Created by DannyRoastBeef㊙ on 7/3/2023 in #help

❔ Can anyone break down this one-line code for me?

builder.Services.AddHttpClient<CatalogueService>(catalogueClient => { catalogueClient.BaseAddress = new Uri(""); });

builder.Services.AddHttpClient<CatalogueService>(catalogueClient => { catalogueClient.BaseAddress = new Uri(""); });

I'm following a tutorial surrounding using HttpClient properly. When adding as a service I noticed a syntax I don't think I've used before and I can't quite make sense of it. I think I understand that I'm setting the base address on the injected

catalogueClient

catalogueClient

but how is it doing it? What is

catalogueClient => { catalogueClient.BaseAddress = new Uri(""); }

catalogueClient => { catalogueClient.BaseAddress = new Uri(""); }

actually doing here? The parameter is

Action<HttpClient> configureClient

Action<HttpClient> configureClient

Thanks.

11 replies

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