学习 C# 中的建造者模式
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使用简单的电视建造者在 C# 中解释建造者模式
引言
设计模式非常有用，可以帮助解决许多实时问题。在本文中，我们将尝试通过一个 C# 示例程序来理解建造者模式。
背景
建造者模式属于创建型模式，因为它处理的是对象创建。这种模式在 .NET Framework 中被多次使用。一个例子是 ConnectionStringBuilder。当我们需要使用一系列复杂的流程来创建一个产品，而每个流程都可以分离时，建造者模式就派上了用场。这意味着我们可以分离对象创建的每个步骤，并且可以使用相同的对象机制来创建类似的产品或对象。
GoF 将建造者模式描述为将复杂对象的构建与其表示分离，以便相同的构建过程可以创建不同的表示。建造者模式包含以下项目
Director:Director负责使用Builder接口或基类创建对象。Builder: 基类或接口，其中提到了创建Product的不同步骤。ConcreteBuilder: 定义了具体的建造者，它是上述Builder的实现。具体的Builder将帮助我们使用Builder中提到的一系列步骤来创建和获取下面的Product。Product: 最终的Product，它将通过许多复杂的步骤来创建。
Using the Code
为了开始示例程序，我创建了一个 Television (Product) 类，如下所示。这个 Product 将由 Builder 构建。我添加了不同的属性来显示产品的不同部分。
/// <summary>
/// Television - Product
/// </summary>
class Television
{
public string Code { get; set; }
public string DisplayTechnology { get; set; }
public string HDFormat { get; set; }
public string ScreenType { get; set; }
public string Size { get; set; }
public string Feature { get; set; }
}
现在，我们将创建 TelevisionBuilder (Builder)，它将定义创建 Product 的复杂步骤。我们可以将 Builder 创建为接口或基类。如果您查看下面的类定义，您可以看到创建 Product 的步骤以及访问已创建 Product 的属性或方法。
/// <summary>
/// TelevisionBuilder - Builder
/// </summary>
abstract class TelevisionBuilder
{
protected Television television;
public abstract void SetCode(); // ProductCode
public abstract void SetDisplayTechnology(); // LCD, LED, OLED, Plasma, CRT
public abstract void SetHDFormat(); // Full HD, HD Ready, Ultra HD, None
public abstract void SetScreenType(); // Curved, Flat, Standard
public abstract void SetSize(); // 22, 32, 40, 42, 54
public abstract void SetFeature(); // 3D, Smart, Standard , HDMI Ports,
// USB Ports, Built in WIFI, Ethernet, Remote
//GetProduct
public Television Television
{
get { return television; }
}
}
定义 FullHD40TVBuilder (ConcreteBuilder1) 及其相应的实现。
/// <summary>
/// FullHD40TVBuilder - ConcreteBuilder1
/// </summary>
class FullHD40TVBuilder : TelevisionBuilder
{
public FullHD40TVBuilder()
{
television = new Television();
}
public override void SetCode()
{
television.Code = "FullHD40TV";
}
public override void SetDisplayTechnology()
{
television.DisplayTechnology = "LCD";
}
public override void SetHDFormat()
{
television.HDFormat = "FullHD";
}
public override void SetScreenType()
{
television.ScreenType="Flat";
}
public override void SetSize()
{
television.Size="40";
}
public override void SetFeature()
{
television.Feature = "1 HDMI Ports, 1 USB Ports, Remote";
}
}
定义 SMARTLED54TVBuilder (ConcreteBuilder2) 及其相应的实现。
/// <summary>
/// SMARTLED54TVBuilder - ConcreteBuilder2
/// </summary>
class SMARTLED54TVBuilder : TelevisionBuilder
{
public SMARTLED54TVBuilder()
{
television = new Television();
}
public override void SetCode()
{
television.Code = "SMARTLED54TV";
}
public override void SetDisplayTechnology()
{
television.DisplayTechnology = "LED";
}
public override void SetHDFormat()
{
television.HDFormat = "FullHD";
}
public override void SetScreenType()
{
television.ScreenType="Flat";
}
public override void SetSize()
{
television.Size="54";
}
public override void SetFeature()
{
television.Feature="2 HDMI Ports, 2 USB Ports, Built in WIFI, Ethernet, Remote";
}
}
定义 Curved4K65LEDTVBuilder (ConcreteBuilder3) 及其相应的实现。
/// <summary>
/// Curved4K65LEDTVBuilder - ConcreteBuilder3
/// </summary>
class Curved4K65LEDTVBuilder : TelevisionBuilder
{
public Curved4K65LEDTVBuilder()
{
television = new Television();
}
public override void SetCode()
{
television.Code = "Curved4K65LEDTV";
}
public override void SetDisplayTechnology()
{
television.DisplayTechnology = "LED";
}
public override void SetHDFormat()
{
television.HDFormat = "4K Ultra HD";
}
public override void SetScreenType()
{
television.ScreenType="Curved";
}
public override void SetSize()
{
television.Size="65";
}
public override void SetFeature()
{
television.Feature="3 HDMI Ports, 2 USB Ports,
Built in WIFI, Ethernet, Smart Remote";
}
}
定义 LCD22TVBuilder (ConcreteBuilder4) 及其相应的实现。
/// <summary>
/// LCD22TVBuilder - ConcreteBuilder4
/// </summary>
class LCD22TVBuilder : TelevisionBuilder
{
public LCD22TVBuilder()
{
television = new Television();
}
public override void SetCode()
{
television.Code = "LCD22TV";
}
public override void SetDisplayTechnology()
{
television.DisplayTechnology = "LCD";
}
public override void SetHDFormat()
{
television.HDFormat = "None";
}
public override void SetScreenType()
{
television.ScreenType = "Flat";
}
public override void SetSize()
{
television.Size = "22";
}
public override void SetFeature()
{
television.Feature = "Remote";
}
}
到目前为止，我们已经定义了 Product、Builder 和 ConcreteBuilder。现在让我们创建 TelevisionManufacturer 作为 Director，这里的参数是 Builder，并且 Director 负责根据需求调用这些步骤。
/// <summary>
/// TelevisionManufacturer - Director
/// </summary>
class TelevisionManufacturer
{
//Constructing Product
public void Construct(TelevisionBuilder televisionBuilder)
{
//Series of Complex Process
televisionBuilder.SetCode();
televisionBuilder.SetDisplayTechnology();
televisionBuilder.SetHDFormat();
televisionBuilder.SetScreenType();
televisionBuilder.SetSize();
televisionBuilder.SetFeature();
}
}
我创建了一个控制台 Program 来测试建造者模式示例，这里的最终客户端根本不用担心复杂的对象创建。
/// <summary>
/// Program class which demonstrates the builder usage
/// </summary>
class Program
{
/// <summary>
/// Main method of Program.cs
/// </summary>
/// <param name="args"></param>
static void Main(string[] args)
{
TelevisionBuilder builder;
TelevisionManufacturer director = new TelevisionManufacturer();
builder = new FullHD40TVBuilder();
director.Construct(builder);
Television product1 = builder.Television;
Console.WriteLine("Code:{0}", product1.Code);
builder = new SMARTLED54TVBuilder();
director.Construct(builder);
Television product2 = builder.Television;
Console.WriteLine("Code:{0}", product2.Code);
builder = new Curved4K65LEDTVBuilder();
director.Construct(builder);
Television product3 = builder.Television;
Console.WriteLine("Code:{0}", product3.Code);
builder = new LCD22TVBuilder();
director.Construct(builder);
Television product4 = builder.Television;
Console.WriteLine("Code:{0}", product4.Code);
//Wait for UserInteraction
Console.ReadKey();
}
}
输出
为了使代码看起来简单，已从上面的 Console.Writeline 中删除了一些代码。您可以参考附加项目中的 *Program.cs* 文件以查看最终版本。
要自己探索此示例，您可以下载附加的代码或创建一个名为“BuilderPatternSample”的控制台项目，并将 *Program.cs* 的内容替换为以下代码块。
Program.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace BuilderPatternSample
{
/// <summary>
/// Program class which demonstrates the builder usage
/// </summary>
class Program
{
/// <summary>
/// Main method of Program.cs
/// </summary>
/// <param name="args"></param>
static void Main(string[] args)
{
TelevisionBuilder builder;
TelevisionManufacturer director = new TelevisionManufacturer();
builder = new FullHD40TVBuilder();
director.Construct(builder);
Television product1 = builder.Television;
Console.WriteLine(" ┌───────────────────────────────────Code:{0}───────────────────────────────┐",
product1.Code);
Console.WriteLine(" │ DisplayTechnology:{0} │",
product1.DisplayTechnology);
Console.WriteLine(" │ HDFormat:{0} │",
product1.HDFormat);
Console.WriteLine(" │ ScreenType:{0} │",
product1.ScreenType);
Console.WriteLine(" │ Size:{0} │",
product1.Size);
Console.WriteLine(" │ Feature:{0} │", product1.Feature);
Console.WriteLine(" └─────────────────────────────────────────────────────────────────────────────────┘");
builder = new SMARTLED54TVBuilder();
director.Construct(builder);
Television product2 = builder.Television;
Console.WriteLine(" ┌──────────────────────────────────Code:{0}──────────────────────────────┐",
product2.Code);
Console.WriteLine(" │ DisplayTechnology:{0} │",
product2.DisplayTechnology);
Console.WriteLine(" │ HDFormat:{0} │",
product2.HDFormat);
Console.WriteLine(" │ ScreenType:{0} │",
product2.ScreenType);
Console.WriteLine(" │ Size:{0} │",
product2.Size);
Console.WriteLine(" │ Feature:{0} │", product2.Feature);
Console.WriteLine(" └─────────────────────────────────────────────────────────────────────────────────┘");
builder = new Curved4K65LEDTVBuilder();
director.Construct(builder);
Television product3 = builder.Television;
Console.WriteLine(" ┌─────────────────────────────────Code:{0}────────────────────────────┐",
product3.Code);
Console.WriteLine(" │ DisplayTechnology:{0} │",
product3.DisplayTechnology);
Console.WriteLine(" │ HDFormat:{0} │",
product3.HDFormat);
Console.WriteLine(" │ ScreenType:{0} │",
product3.ScreenType);
Console.WriteLine(" │ Size:{0} │",
product3.Size);
Console.WriteLine(" │ Feature:{0} │", product3.Feature);
Console.WriteLine(" └─────────────────────────────────────────────────────────────────────────────────┘");
builder = new LCD22TVBuilder();
director.Construct(builder);
Television product4 = builder.Television;
Console.WriteLine(" ┌────────────────────────────────────Code:{0}─────────────────────────────────┐",
product4.Code);
Console.WriteLine(" │ DisplayTechnology:{0} │",
product4.DisplayTechnology);
Console.WriteLine(" │ HDFormat:{0} │",
product4.HDFormat);
Console.WriteLine(" │ ScreenType:{0} │",
product4.ScreenType);
Console.WriteLine(" │ Size:{0} │",
product4.Size);
Console.WriteLine(" │ Feature:{0} │",
product4.Feature);
Console.WriteLine(" └─────────────────────────────────────────────────────────────────────────────────┘");
//Wait for UserInteraction
Console.ReadKey();
}
}
/// <summary>
/// Television - Product
/// </summary>
class Television
{
public string Code { get; set; }
public string DisplayTechnology { get; set; }
public string HDFormat { get; set; }
public string ScreenType { get; set; }
public string Size { get; set; }
public string Feature { get; set; }
}
/// <summary>
/// TelevisionBuilder - Builder
/// </summary>
abstract class TelevisionBuilder
{
protected Television television;
public abstract void SetCode(); // ProductCode
public abstract void SetDisplayTechnology(); // LCD, LED, OLED, Plasma, CRT
public abstract void SetHDFormat(); // Full HD, HD Ready, Ultra HD, None
public abstract void SetScreenType(); // Curved, Flat, Standard
public abstract void SetSize(); // 22, 32, 40, 42, 54
public abstract void SetFeature(); // 3D, Smart, Standard , HDMI Ports,
// USB Ports, Built in WIFI, Ethernet, Remote
//GetProduct
public Television Television
{
get { return television; }
}
}
/// <summary>
/// FullHD40TVBuilder - ConcreteBuilder1
/// </summary>
class FullHD40TVBuilder : TelevisionBuilder
{
public FullHD40TVBuilder()
{
television = new Television();
}
public override void SetCode()
{
television.Code = "FullHD40TV";
}
public override void SetDisplayTechnology()
{
television.DisplayTechnology = "LCD";
}
public override void SetHDFormat()
{
television.HDFormat = "FullHD";
}
public override void SetScreenType()
{
television.ScreenType = "Flat";
}
public override void SetSize()
{
television.Size = "40";
}
public override void SetFeature()
{
television.Feature = "1 HDMI Ports, 1 USB Ports, Remote";
}
}
/// <summary>
/// SMARTLED54TVBuilder - ConcreteBuilder2
/// </summary>
class SMARTLED54TVBuilder : TelevisionBuilder
{
public SMARTLED54TVBuilder()
{
television = new Television();
}
public override void SetCode()
{
television.Code = "SMARTLED54TV";
}
public override void SetDisplayTechnology()
{
television.DisplayTechnology = "LED";
}
public override void SetHDFormat()
{
television.HDFormat = "FullHD";
}
public override void SetScreenType()
{
television.ScreenType = "Flat";
}
public override void SetSize()
{
television.Size = "54";
}
public override void SetFeature()
{
television.Feature = "2 HDMI Ports,
2 USB Ports, Built in WIFI, Ethernet, Remote";
}
}
/// <summary>
/// Curved4K65LEDTVBuilder - ConcreteBuilder3
/// </summary>
class Curved4K65LEDTVBuilder : TelevisionBuilder
{
public Curved4K65LEDTVBuilder()
{
television = new Television();
}
public override void SetCode()
{
television.Code = "Curved4K65LEDTV";
}
public override void SetDisplayTechnology()
{
television.DisplayTechnology = "LED";
}
public override void SetHDFormat()
{
television.HDFormat = "4K Ultra HD";
}
public override void SetScreenType()
{
television.ScreenType = "Curved";
}
public override void SetSize()
{
television.Size = "65";
}
public override void SetFeature()
{
television.Feature = "3 HDMI Ports, 2 USB Ports, Built in WIFI,
Ethernet, Smart Remote";
}
}
/// <summary>
/// LCD22TVBuilder - ConcreteBuilder4
/// </summary>
class LCD22TVBuilder : TelevisionBuilder
{
public LCD22TVBuilder()
{
television = new Television();
}
public override void SetCode()
{
television.Code = "LCD22TV";
}
public override void SetDisplayTechnology()
{
television.DisplayTechnology = "LCD";
}
public override void SetHDFormat()
{
television.HDFormat = "None";
}
public override void SetScreenType()
{
television.ScreenType = "Flat";
}
public override void SetSize()
{
television.Size = "22";
}
public override void SetFeature()
{
television.Feature = "Remote";
}
}
/// <summary>
/// TelevisionManufacturer - Director
/// </summary>
class TelevisionManufacturer
{
//Constructing Product
public void Construct(TelevisionBuilder televisionBuilder)
{
//Series of Complex Process
televisionBuilder.SetCode();
televisionBuilder.SetDisplayTechnology();
televisionBuilder.SetHDFormat();
televisionBuilder.SetScreenType();
televisionBuilder.SetSize();
televisionBuilder.SetFeature();
}
}
}
摘要
在本文中，我用一个简单的 C# 应用程序解释了建造者模式。我希望您喜欢这篇文章，并且您的知识得到了一些增值。请不要忘记标记您的投票、建议和反馈，以提高本文和即将发布的文章的质量。
历史
- 2016 年 2 月 29 日：初始版本