Multiple selection example lacks attribute

[Iamnvincible]

Description

The original code example to do multiple selection is

<InputSelect @bind-Value="Model!.SelectedClassification">

However, to do multiple section, the InputSelect should add multiple.
That is

<InputSelect @bind-Value="Model!.SelectedClassification" multiple>

Moreover, in the following razor code

@if (Model?.SelectedClassification?.Length > 0)
{
    <div>@string.Join(", ", Model.SelectedClassification)</div>
}

That won't make any change if the component is not set InteractiveServer rendermode.
So the redermode should be put at the top of code

@page "/starship-5"
@using System.ComponentModel.DataAnnotations
@inject ILogger<Starship5> Logger
@rendermode InteractiveServer

Page URL

https://learn.microsoft.com/en-us/aspnet/core/blazor/forms/input-components?view=aspnetcore-8.0

Content source URL

https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/blazor/forms/input-components.md

Document ID

52ee411b-69fe-c0bc-5305-846d9384ebbd

Platform Id

ebc8ed08-0e4e-884d-e47b-d27b203d1205

Article author

@guardrex

Metadata

• ID: 52ee411b-69fe-c0bc-5305-846d9384ebbd
• PlatformId: ebc8ed08-0e4e-884d-e47b-d27b203d1205
• Service: aspnet-core
• Sub-service: blazor

Related Issues

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[guardrex]

Hello @Iamnvincible ...

to do multiple section, the InputSelect should add multiple

The component adds it for you ...

Reference Source: https://github.com/dotnet/aspnetcore/blob/main/src/Components/Web/src/Forms/InputSelect.cs#L45

if the component is not set InteractiveServer rendermode

All sample code for BWAs requires an interactive render mode, and we assume that it's applied globally. We don't add them to every code sample because most of the time devs use a global interactive render mode and because Blazor WebAssembly apps don't have a render mode concept.

See the blue IMPORTANT note in ...

https://learn.microsoft.com/en-us/aspnet/core/blazor/fundamentals/?view=aspnetcore-8.0#static-and-interactive-rendering-concepts

... and the section on it in the Render Modes article ...

https://learn.microsoft.com/en-us/aspnet/core/blazor/components/render-modes?view=aspnetcore-8.0#blazor-documentation-examples-for-blazor-web-apps

I think the coverage on InputSelect should tell readers that multiple is added automatically, so I'll write that into the article now. I'll ping you on the PR in a few minutes.

[guardrex]

I probably don't really need to change it. The section already states ...

The value must be bound to an array type, and binding to an array type makes the multiple attribute optional on the InputSelect tag.

However, I can clarify that the attribute will be added automatically. I don't like the "optional" phrasing in spite of that being true.