通过Blazor使用C#开发SPA单页面应用程序(4) - Ant Design Button - 好文

前面学习了Blazor的特点、环境搭建及基础知识，现在我们尝试的做个实际的组件。

Ant Design <https://ant.design/index-cn>是蚂蚁金服是基于Ant Design设计体系的 UI
组件库，主要用于研发企业级中后台产品。目前官方是基于React和Angular实现的，今年也推出了Vue的实现。其组件涵盖面较广，其组件风格及交互效果还是比较惊艳的，后面准备利用Ant
Design的样式文件利用Blazor模仿几个组件的实现。

由于也是新学的Blazor开发，可能实现的方式有些笨拙，希望高手提出宝贵意见，先看看实现的Button 按钮、Grid 栅格、导航栏的效果。

先来看看Button按钮，它支持多种风格，是否只显示图标，loading状态等。实现步骤及主要代码且听我娓娓道来，

1、引用样式文件

首先去antd.css cdn <https://www.bootcdn.cn/antd/> 下载稳定版的css文件，放到 wwwroot 文件夹下。再
_Host.cshtml 引用该文件。

2、建立 AButtonBase 类

AButtonBase类定义了按钮的属性参数；注册了class名称（例如：class="ant-btn
ant-btn-primary"）的计算表达式，class内容是根据属性参数的设置情况计算出来的。

属性set 的 ClassMapper.Dirty() 是通知样式名生成方法属性改变了需要重新生成样式名称。

而ClassMapper是用于注册组件需要用到的样式构建类，PrefixCls（）是添加样式共用的前缀，Add有多个重载，可以是直接的样式名称；也可以是根据第一个参数的bool表达式来确定，第二个参数的样式是否启用。

using BlazorAntDesign.Core; using Microsoft.AspNetCore.Components; using
Microsoft.AspNetCore.Components.RenderTree;using System; using
System.Collections.Generic;using System.Linq; using System.Threading.Tasks;
namespace BlazorAntDesign.General { public class AButtonBase : BaseComponent {
#region Properties /// <summary> /// 设置按钮大小，可选值为 Small、Large 或者不设 /// </summary>
[Parameter]protected AButtonSizes ButtonSize { get => buttonSize; set {
buttonSize= value; ClassMapper.Dirty(); } } private AButtonSizes buttonSize =
AButtonSizes.Default;/// <summary> /// 设置按钮类型，可选值为 Primary、Dashed、Danger 或者不设
/// </summary> [Parameter] protected AButtonTypes ButtonType { get =>
buttonType;set { buttonType = value; ClassMapper.Dirty(); } } private
AButtonTypes buttonType = AButtonTypes.Default; /// <summary> /// 设置按钮形状，可选值为
Circle、 Round 或者不设/// </summary> [Parameter] protected AButtonShapes
ButtonShape {get => buttonShape; set { buttonShape = value;
ClassMapper.Dirty(); } }private AButtonShapes buttonShape =
AButtonShapes.Default;/// <summary> /// 设置 button 原生的 type 值，可选值请参考 HTML 标准 ///
</summary> [Parameter] protected AButtonHTMLTypes HtmlType { get; set; } =
AButtonHTMLTypes.Button;/// <summary> /// 按钮标题 /// </summary> [Parameter]
protected string Title { get => title; set { title = value;
ClassMapper.Dirty(); } }private string title; /// <summary> /// 设置按钮的图标名称 ///
</summary> [Parameter] protected string IconName { get; set; } /// <summary>
/// 将按钮宽度调整为其父宽度的选项 /// </summary> [Parameter] protected bool Block { get =>
block;set { block = value; ClassMapper.Dirty(); } } private bool block; ///
<summary> /// 幽灵属性，使按钮背景透明。幽灵按钮将按钮的内容反色，背景变为透明，常用在有色背景上。 /// </summary>
[Parameter]protected bool Ghost { get => ghost; set { ghost = value;
ClassMapper.Dirty(); } }private bool ghost; /// <summary> /// 设置按钮载入状态 ///
</summary> [Parameter] protected bool Loading { get => loading; set { loading =
value; ClassMapper.Dirty(); } }private bool loading; /// <summary> /// 按钮失效状态
/// </summary> [Parameter] protected bool Disabled { get; set; } [Parameter]
protected RenderFragment ChildContent { get; set; } /// <summary> /// 点击按钮时的回调
/// </summary> [Parameter] public EventCallback<UIMouseEventArgs> OnClick { get
;set; } //protected System.Action Clicked { get; set; } protected bool
click_animating {get; set; } #endregion protected override void
RegisterClasses() { ClassMapper.PrefixCls("ant-btn") .Add(() =>
ClassMapper.GetEnumName(buttonSize)) .Add(()=>
ClassMapper.GetEnumName(buttonType)) .Add(()=>
ClassMapper.GetEnumName(buttonShape)) .Add(()=> Block, () => "block") .Add(()
=> Ghost, () =>"background-ghost") .Add(() => Loading, () => "loading") .Add(()
=>string.IsNullOrEmpty(title) && ChildContent == null, () => "icon-only"); base
.RegisterClasses(); }protected void buttonDown() { click_animating = false; }
protected void buttonUp() { click_animating = true; } } }
AButtonSizes、AButtonTypes、AButtonShapes、AButtonHTMLTypes 属性参数是定义的枚举，例如：
namespace BlazorAntDesign.General { /// <summary> /// 按钮尺寸选项 /// </summary>
public enum AButtonSizes { /// <summary> /// 缺省，中 /// </summary> [ClassNamePart(
"")] Default, /// <summary> /// 大 /// </summary> [ClassNamePart("lg")] Large,
/// <summary> /// 小 /// </summary> [ClassNamePart("sm")] Small } }

namespace BlazorAntDesign.General { /// <summary> /// 按钮类型选项 /// </summary>
public enum AButtonTypes { /// <summary> /// 缺省，次按钮 /// </summary>
[ClassNamePart("")] Default, /// <summary> /// 主按钮 /// </summary> Primary, ///
<summary> /// /// </summary> Ghost, /// <summary> /// 虚线按钮 /// </summary>
Dashed,

Danger } }
   AButtonBase类继承自自定义的BaseComponent，BaseComponent继承自Blazor的ComponentBase类。

  BaseComponent主要定义了所有组件共用的属性，ElementId、Style、ClassMapper等，
using System; using System.Collections.Generic; using System.Linq; using
System.Threading.Tasks;using Microsoft.AspNetCore.Components; namespace
BlazorAntDesign.Core {public abstract class BaseComponent : ComponentBase,
IDisposable {#region Members private bool disposed; private ElementRef
elementRef;#endregion #region Constructors public BaseComponent() { ElementId =
Utils.IDGenerator.Instance.Generate; ClassMapper= new ClassMapper();
RegisterClasses(); }#endregion #region Methods protected virtual void
RegisterClasses() { ClassMapper.AddCustomClass(()=> customClass); } public void
Dispose() { Dispose(true); GC.SuppressFinalize(this); } protected virtual void
Dispose(bool disposing) { if (!disposed) { if (disposing) { if (ClassMapper !=
null) { //ClassMapper.Dispose(); ClassMapper = null; } } disposed = true; } }
#endregion #region Properties /// <summary> /// 定义用户自定义的 ClassName ///
</summary> [Parameter] protected string ClassName { get => customClass; set {
customClass= value; ClassMapper.Dirty(); } } private string customClass; ///
<summary> /// Gets the reference to the rendered element. /// </summary> public
ElementRef ElementRef {get => elementRef; protected set => elementRef = value; }
/// <summary> /// 获取 element 唯一 Id. /// </summary> public string ElementId { get
; } [Parameter]protected string Style { get; set; } /// <summary> /// 获取
ClassMapper./// </summary> protected ClassMapper ClassMapper { get; private set
; }#endregion } }

3、建立 AButton.razor
@inherits BlazorAntDesign.General.AButtonBase <button class
="@ClassMapper.Class" type="@(Enum.GetName(typeof(AButtonHTMLTypes),
HtmlType).ToLower())" ant-click-animating-without-extra-node="@(click_animating
? "true" : "")" disabled="@Disabled" @onkeydown="@buttonDown" @onmousedown
="@buttonDown" @onkeyup="@buttonUp" @onmouseup="@buttonUp" @onclick="@OnClick">
@*图标*@ @if (Loading) {<AIcon IconName="loading"></AIcon>} else { if
(!string.IsNullOrEmpty(IconName)) {<AIcon IconName="@IconName"></AIcon>} }
@*标题*@ @if (!string.IsNullOrEmpty(Title)) {<span>@Title</span>} @*子内容*@
@ChildContent</button>
其中 @inherits BlazorAntDesign.General.AButtonBase
是代码隐藏方式，指定后台代码继承自AButtonBase类，button class="@ClassMapper.Class"
，将采用的样式根据指定的属性值计算出来赋值给button的class属性。下面根据属性设置判断是否显示图标、标题、子内容。

4、使用 AButton

建立DemoButton.razor文件，样例代码如下：

@page "/DemoButton" @using BlazorAntDesign.General; <div style="border:1px
solid beige;padding:10px"> <AButton Title="Default"></AButton> <AButton Title
="Primary" ButtonType="AButtonTypes.Primary"></AButton> <AButton Title="Danger"
ButtonType="AButtonTypes.Danger"></AButton> <AButton Title="Dashed" ButtonType
="AButtonTypes.Dashed"></AButton> <AButton Title="Disabled" Disabled="true"></
AButton> <AButton ButtonType="AButtonTypes.Primary" IconName="download"
ButtonShape="AButtonShapes.Circle"></AButton> <AButton Title="下载" ButtonType
="AButtonTypes.Primary" IconName="download" ButtonShape="AButtonShapes.Round"></
AButton> <AButton Title="下载" ButtonType="AButtonTypes.Primary" IconName
="download"></AButton> <AButtonGroup><AButton ButtonType="AButtonTypes.Primary"
IconName="left">Backward</AButton><AButton ButtonType="AButtonTypes.Primary">
Forward<AIcon IconName="right" /></AButton></AButtonGroup> <AButton Title
="Loading" ButtonType="AButtonTypes.Primary" Loading="true"></AButton> <AButton
Title="Click me!" ButtonType="AButtonTypes.Primary" Loading="@isLoading" OnClick
="@(()=> { isLoading = true; })"></AButton> </div> <div style="border:1px solid
beige;padding:10px;margin-top:5px"> <AButton IconName="search" ButtonType
="AButtonTypes.Primary" ButtonShape="AButtonShapes.Circle"></AButton> <AButton
IconName="search" ButtonType="AButtonTypes.Primary">按钮</AButton> <AButton
IconName="search" ButtonShape="AButtonShapes.Circle"></AButton> <AButton
IconName="search">按钮</AButton> <AButton IconName="search" ButtonType
="AButtonTypes.Dashed" ButtonShape="AButtonShapes.Circle"></AButton> <AButton
IconName="search" ButtonType="AButtonTypes.Primary">按钮</AButton> </div> @code{
private bool isLoading = false; private void LoadingClick() { isLoading = true;
} }

@page "/DemoButton" 为组件路由

@using BlazorAntDesign.General; 为应用组件命名空间

   好了Button的实现思路今天就学习到这了，希望有兴趣的同仁共同学习探讨，让Blazor真正走向SPA开发的舞台，让.net
core七龙珠面向全栈开发，更好的拥抱社区，刷新业界对.net体系的认知。

   番外篇

   Blazor 在发展：

微软已将 Blazor 移出了实验阶段，进入了官方预览版。使用组件模型进行服务器端渲染的 Blazor 版本将与.NET Core 3
的最终版本一起发布（请参阅.NET Core 路线图
<https://github.com/dotnet/core/blob/master/roadmap.md>
），客户端版本将在随后不久发布。还有工作要完成：调试体验极其有限，必须改进；有机会通过提前编译生成本机 Wasm
来优化代码性能；在将未使用的代码库发送到浏览器之前，需要从库中删除未使用的代码，从而降低总体大小（这个过程称为树抖动）。对 WebAsssembly
的兴趣和采用与日俱增，借助 Blazor，编写可以在任何地方运行的 C#和.NET 代码的梦想终于实现了。

.net core将踏上新的征程：

<https://devblogs.microsoft.com/dotnet/introducing-net-5/>

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