aspnetcore/src/Microsoft.Blazor.Browser/Rendering/BrowserRendererEventDispatc...

64 lines
2.7 KiB
C#

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using Microsoft.Blazor.Browser.Interop;
using Microsoft.Blazor.RenderTree;
using System;
namespace Microsoft.Blazor.Browser.Rendering
{
/// <summary>
/// Provides mechanisms for dispatching events to components in a <see cref="BrowserRenderer"/>.
/// This is marked 'internal' because it only gets invoked from JS code.
/// </summary>
internal static class BrowserRendererEventDispatcher
{
// We receive the information as JSON strings because of current interop limitations:
// - Can't pass unboxed value types from JS to .NET (yet all the IDs are ints)
// - Can't pass more than 4 args from JS to .NET
// This can be simplified in the future when the Mono WASM runtime is enhanced.
public static void DispatchEvent(string eventDescriptorJson, string eventArgsJson)
{
var eventDescriptor = Json.Deserialize<BrowserEventDescriptor>(eventDescriptorJson);
var eventArgs = ParseEventArgsJson(eventDescriptor.EventArgsType, eventArgsJson);
var browserRenderer = BrowserRendererRegistry.Find(eventDescriptor.BrowserRendererId);
browserRenderer.DispatchBrowserEvent(
eventDescriptor.ComponentId,
eventDescriptor.RenderTreeNodeIndex,
eventArgs);
}
// Again, the params are received as strings for the same reason as above and
// can be simplified once runtime support improves.
public static void RenderChildComponent(
string browserRendererId,
string componentId)
{
var browserRenderer = BrowserRendererRegistry.Find(int.Parse(browserRendererId));
browserRenderer.RenderComponentInternal(
int.Parse(componentId));
}
private static UIEventArgs ParseEventArgsJson(string eventArgsType, string eventArgsJson)
{
switch (eventArgsType)
{
case "mouse":
return Json.Deserialize<UIMouseEventArgs>(eventArgsJson);
case "keyboard":
return Json.Deserialize<UIKeyboardEventArgs>(eventArgsJson);
default:
throw new ArgumentException($"Unsupported value '{eventArgsType}'.", nameof(eventArgsType));
}
}
private class BrowserEventDescriptor
{
public int BrowserRendererId { get; set; }
public int ComponentId { get; set; }
public int RenderTreeNodeIndex { get; set; }
public string EventArgsType { get; set; }
}
}
}