70 lines
2.6 KiB
C#
70 lines
2.6 KiB
C#
// Copyright (c) .NET Foundation. All rights reserved.
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// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
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using System;
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using Microsoft.AspNetCore.Blazor.Components;
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using Microsoft.AspNetCore.Blazor.RenderTree;
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namespace BasicTestApp
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{
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public class RenderBlockComponent : IComponent, IHandleEvent
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{
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private RenderHandle _renderHandle;
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private bool _showRegion;
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// Important: Notice that the sequence numbers inside the fragment are higher
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// that the sequence numbers outside it. Without the region delimiter, the
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// differencer would think the following nodes had been removed, then the
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// region was inserted, followed by a new copy of the following nodes. That's
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// not as efficient and wouldn't preserve focus etc.
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private RenderFragment _exampleContent = builder =>
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{
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builder.OpenElement(100, "p");
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builder.AddAttribute(101, "name", "region-element");
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builder.AddAttribute(102, "style", "color: red");
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builder.AddContent(103, "This is from the region");
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builder.CloseElement();
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};
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public void Init(RenderHandle renderHandle)
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=> _renderHandle = renderHandle;
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public void SetParameters(ParameterCollection parameters)
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=> Render();
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public void HandleEvent(UIEventHandler handler, UIEventArgs args)
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{
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// TODO: Remove the necessity to implement IHandleEvent if you just want
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// the event handler to be called. Then call Render from inside the handler.
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handler(args);
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Render();
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}
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private void Render() => _renderHandle.Render(builder =>
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{
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builder.OpenElement(0, "div"); // Container so we can see that passing through regions is OK
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builder.OpenRegion(1);
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builder.AddContent(2, "Region will be toggled below ");
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if (_showRegion)
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{
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builder.AddContent(3, _exampleContent);
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}
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builder.OpenElement(4, "button");
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builder.AddAttribute(5, "onclick", ToggleRegion);
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builder.AddContent(6, "Toggle");
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builder.CloseElement();
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builder.CloseRegion();
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builder.OpenElement(7, "p");
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builder.AddContent(8, "The end");
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builder.CloseElement();
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builder.CloseElement();
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});
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private void ToggleRegion(UIEventArgs eventArgs)
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=> _showRegion = !_showRegion;
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}
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}
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