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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
#nullable disable warnings
using System.Collections.Concurrent;
using System.Diagnostics.CodeAnalysis;
using System.Reflection;
using Microsoft.AspNetCore.Components.HotReload;
using Microsoft.AspNetCore.Components.Rendering;
namespace Microsoft.AspNetCore.Components;
/// <summary>
/// Displays the specified page component, rendering it inside its layout
/// and any further nested layouts.
/// </summary>
public class RouteView : IComponent
{
private RenderHandle _renderHandle;
private static readonly ConcurrentDictionary<Type, Type?> _layoutAttributeCache = new();
static RouteView()
{
if (HotReloadManager.Default.MetadataUpdateSupported)
{
HotReloadManager.Default.OnDeltaApplied += _layoutAttributeCache.Clear;
}
}
[Inject]
private NavigationManager NavigationManager { get; set; }
/// <summary>
/// Gets or sets the route data. This determines the page that will be
/// displayed and the parameter values that will be supplied to the page.
/// </summary>
[Parameter]
[EditorRequired]
public RouteData RouteData { get; set; }
/// <summary>
/// Gets or sets the type of a layout to be used if the page does not
/// declare any layout. If specified, the type must implement <see cref="IComponent"/>
/// and accept a parameter named <see cref="LayoutComponentBase.Body"/>.
/// </summary>
[Parameter]
public Type DefaultLayout { get; set; }
/// <inheritdoc />
public void Attach(RenderHandle renderHandle)
{
_renderHandle = renderHandle;
}
/// <inheritdoc />
public Task SetParametersAsync(ParameterView parameters)
{
parameters.SetParameterProperties(this);
if (RouteData == null)
{
throw new InvalidOperationException($"The {nameof(RouteView)} component requires a non-null value for the parameter {nameof(RouteData)}.");
}
_renderHandle.Render(Render);
return Task.CompletedTask;
}
/// <summary>
/// Renders the component.
/// </summary>
/// <param name="builder">The <see cref="RenderTreeBuilder"/>.</param>
[UnconditionalSuppressMessage("Trimming", "IL2111", Justification = "Layout components are preserved because the LayoutAttribute constructor parameter is correctly annotated.")]
[UnconditionalSuppressMessage("Trimming", "IL2118", Justification = "Layout components are preserved because the LayoutAttribute constructor parameter is correctly annotated.")]
protected virtual void Render(RenderTreeBuilder builder)
{
var pageLayoutType = _layoutAttributeCache
.GetOrAdd(RouteData.PageType, static type => type.GetCustomAttribute<LayoutAttribute>()?.LayoutType)
?? DefaultLayout;
builder.OpenComponent<LayoutView>(0);
builder.AddComponentParameter(1, nameof(LayoutView.Layout), pageLayoutType);
builder.AddComponentParameter(2, nameof(LayoutView.ChildContent), (RenderFragment)RenderPageWithParameters);
builder.CloseComponent();
}
private void RenderPageWithParameters(RenderTreeBuilder builder)
{
builder.OpenComponent(0, RouteData.PageType);
foreach (var kvp in RouteData.RouteValues)
{
builder.AddComponentParameter(1, kvp.Key, kvp.Value);
}
builder.CloseComponent();
}
}
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