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

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 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），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：