aspnetcore/samples/StandaloneApp/Shared/MainLayout.cshtml

@implements ILayoutComponent

<div class="container-fluid">
    <div class="row">
        <div class="col-sm-3">
            <NavMenu />
        </div>
        <div class="col-sm-9">
            @Body
        </div>
    </div>
</div>

@functions
{
    public RenderFragment Body { get; set; }
}