{"id":1638,"date":"2023-04-22T14:43:04","date_gmt":"2023-04-22T07:43:04","guid":{"rendered":"https:\/\/csharptutorial.net\/?page_id=1638"},"modified":"2024-12-14T23:12:14","modified_gmt":"2024-12-14T16:12:14","slug":"csharp-builder-pattern","status":"publish","type":"page","link":"https:\/\/www.csharptutorial.net\/csharp-design-patterns\/csharp-builder-pattern\/","title":{"rendered":"C# Builder Pattern"},"content":{"rendered":"\n<p><strong>Summary<\/strong>: in this tutorial, you will learn how to use the C# builder pattern to create a complex object step by step.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Introduction to the C# builder pattern<\/h2>\n\n\n\n<p>The Builder is a creational design pattern that separates the construction of a complex object from its representation so that you can use the same construction process to create different representations of an object.<\/p>\n\n\n\n<p>In practice, you use the Builder pattern to create objects requiring multiple steps, complex initialization, or configurations.<\/p>\n\n\n\n<p>The following UML diagram illustrates the Builder pattern:<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/csharptutorial.net\/wp-content\/uploads\/2023\/04\/CSharp-Builder-Pattern.svg\" alt=\"C# Builder Pattern\" class=\"wp-image-1644\"\/><\/figure>\n\n\n\n<p>The Builder pattern has four main participants:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>Product<\/code>: This is a class of complex objects with multiple parts.<\/li>\n\n\n\n<li><code>Builder<\/code>: This is an <a href=\"https:\/\/csharptutorial.net\/csharp-tutorial\/csharp-interface\/\">interface <\/a>or <a href=\"https:\/\/csharptutorial.net\/csharp-tutorial\/csharp-abstract-class\/\">abstract class<\/a> that defines the steps for building the <code>Product<\/code>. The <code>Builder<\/code> interface has a set of methods for setting each property of the product.<\/li>\n\n\n\n<li><code>ConcreteBuilder<\/code>: This is a concrete class that implements the <code>IBuilder<\/code> interface. The <code>ConcreteBuilder<\/code> class has specific implementations for each of the methods.<\/li>\n\n\n\n<li><code>Director<\/code>: This is an optional class that controls the order in which the builder&#8217;s methods are called to build the <code>Product<\/code>. The <code>Director<\/code> class may also have additional logic for constructing the <code>Product<\/code>.<\/li>\n<\/ul>\n\n\n\n<p>The following program demonstrates how to implement the Builder pattern in C#:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-1\" data-shcb-language-name=\"C#\" data-shcb-language-slug=\"cs\"><span><code class=\"hljs language-cs\"><span class=\"hljs-keyword\">using<\/span> <span class=\"hljs-keyword\">static<\/span> System.Console;\n\n<span class=\"hljs-keyword\">namespace<\/span> <span class=\"hljs-title\">BuilderPattern<\/span>;\n\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title\">Product<\/span>\n{\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">string<\/span> PartA {   <span class=\"hljs-keyword\">get<\/span>; <span class=\"hljs-keyword\">set<\/span>; }\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">string<\/span> PartB {   <span class=\"hljs-keyword\">get<\/span>; <span class=\"hljs-keyword\">set<\/span>; }\n}\n\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">interface<\/span> <span class=\"hljs-title\">IBuilder<\/span>\n{\n    <span class=\"hljs-function\">IBuilder <span class=\"hljs-title\">BuildPartA<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>;\n    <span class=\"hljs-function\">IBuilder <span class=\"hljs-title\">BuildPartB<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>;\n    <span class=\"hljs-function\">Product <span class=\"hljs-title\">GetProduct<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>;\n}\n\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title\">ConcreteBuilder<\/span> : <span class=\"hljs-title\">IBuilder<\/span>\n{\n    <span class=\"hljs-keyword\">public<\/span> Product _product = <span class=\"hljs-keyword\">new<\/span>();\n\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> IBuilder <span class=\"hljs-title\">BuildPartA<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>\n    {\n        _product.PartA = <span class=\"hljs-string\">\"Part A\"<\/span>;\n        <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-keyword\">this<\/span>;\n    }\n\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> IBuilder <span class=\"hljs-title\">BuildPartB<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>\n    {\n        _product.PartB = <span class=\"hljs-string\">\"Part B\"<\/span>;\n        <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-keyword\">this<\/span>;\n    }\n\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> Product <span class=\"hljs-title\">GetProduct<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>\n    {\n        <span class=\"hljs-keyword\">return<\/span> _product;\n    }\n}\n\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title\">Director<\/span>\n{\n    <span class=\"hljs-keyword\">private<\/span> <span class=\"hljs-keyword\">readonly<\/span> IBuilder _builder;\n\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-title\">Director<\/span>(<span class=\"hljs-params\">IBuilder builder<\/span>)<\/span>\n    {\n        _builder = builder;\n    }\n\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">void<\/span> <span class=\"hljs-title\">Construct<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>\n    {\n        _builder.BuildPartA();\n        _builder.BuildPartB();\n    }\n}\n\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title\">Client<\/span>\n{\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">static<\/span> <span class=\"hljs-keyword\">void<\/span> <span class=\"hljs-title\">Main<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>\n    {\n        <span class=\"hljs-keyword\">var<\/span> builder = <span class=\"hljs-keyword\">new<\/span> ConcreteBuilder();\n        \n        <span class=\"hljs-keyword\">var<\/span> director = <span class=\"hljs-keyword\">new<\/span> Director(builder);\n        director.Construct();\n\n        <span class=\"hljs-keyword\">var<\/span> product = builder.GetProduct();\n        WriteLine(<span class=\"hljs-string\">$\"Product Parts: <span class=\"hljs-subst\">{product.PartA}<\/span>, <span class=\"hljs-subst\">{product.PartB}<\/span>\"<\/span>);\n    }\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">C#<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">cs<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-2\" data-shcb-language-name=\"C#\" data-shcb-language-slug=\"cs\"><span><code class=\"hljs language-cs\">Product Parts: Part A, Part B<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-2\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">C#<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">cs<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>How it works.<\/p>\n\n\n\n<p>First, define a <code>Product<\/code> that has two parts <code>A<\/code> and <code>B<\/code>:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-3\" data-shcb-language-name=\"C#\" data-shcb-language-slug=\"cs\"><span><code class=\"hljs language-cs\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title\">Product<\/span>\n{\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">string<\/span> PartA {   <span class=\"hljs-keyword\">get<\/span>; <span class=\"hljs-keyword\">set<\/span>; }\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">string<\/span> PartB {   <span class=\"hljs-keyword\">get<\/span>; <span class=\"hljs-keyword\">set<\/span>; }\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-3\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">C#<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">cs<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Next, define an <code>IBuilder<\/code> interface that has methods for constructing the <code>Product<\/code> object from parts:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-4\" data-shcb-language-name=\"C#\" data-shcb-language-slug=\"cs\"><span><code class=\"hljs language-cs\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">interface<\/span> <span class=\"hljs-title\">IBuilder<\/span>\n{\n    <span class=\"hljs-function\">IBuilder <span class=\"hljs-title\">BuildPartA<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>;\n    <span class=\"hljs-function\">IBuilder <span class=\"hljs-title\">BuildPartB<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>;\n    <span class=\"hljs-function\">Product <span class=\"hljs-title\">GetProduct<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>;\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-4\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">C#<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">cs<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Then, define a <code>ConcreteBuilder<\/code> class that implements the <code>IBuilder<\/code> interface:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-5\" data-shcb-language-name=\"C#\" data-shcb-language-slug=\"cs\"><span><code class=\"hljs language-cs\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title\">ConcreteBuilder<\/span> : <span class=\"hljs-title\">IBuilder<\/span>\n{\n    <span class=\"hljs-keyword\">public<\/span> Product _product = <span class=\"hljs-keyword\">new<\/span>();\n\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> IBuilder <span class=\"hljs-title\">BuildPartA<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>\n    {\n        _product.PartA = <span class=\"hljs-string\">\"Part A\"<\/span>;\n        <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-keyword\">this<\/span>;\n    }\n\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> IBuilder <span class=\"hljs-title\">BuildPartB<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>\n    {\n        _product.PartB = <span class=\"hljs-string\">\"Part B\"<\/span>;\n        <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-keyword\">this<\/span>;\n    }\n\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> Product <span class=\"hljs-title\">GetProduct<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>\n    {\n        <span class=\"hljs-keyword\">return<\/span> _product;\n    }\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-5\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">C#<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">cs<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>After that, define the <code>Director<\/code> class that constructs the <code>Product<\/code> using an instance of the <code>IBuilder<\/code> interface. The <code>Construct()<\/code> method uses the <code>IBuilder<\/code> instance to construct the <code>Product<\/code>.<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-6\" data-shcb-language-name=\"C#\" data-shcb-language-slug=\"cs\"><span><code class=\"hljs language-cs\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title\">Director<\/span>\n{\n    <span class=\"hljs-keyword\">private<\/span> <span class=\"hljs-keyword\">readonly<\/span> IBuilder _builder;\n\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-title\">Director<\/span>(<span class=\"hljs-params\">IBuilder builder<\/span>)<\/span>\n    {\n        _builder = builder;\n    }\n\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">void<\/span> <span class=\"hljs-title\">Construct<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>\n    {\n        _builder.BuildPartA();\n        _builder.BuildPartB();\n    }\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-6\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">C#<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">cs<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Finally, the <code>Client<\/code> class creates a <code>ConcreteBuilder<\/code> instance, injects it into the constructor of the <code>Director<\/code> object, and then uses the <code>Director<\/code> to construct the <code>Product<\/code>. It gets the <code>Product<\/code> from the <code>GetProduct()<\/code> method of the builder and shows it to the console:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-7\" data-shcb-language-name=\"C#\" data-shcb-language-slug=\"cs\"><span><code class=\"hljs language-cs\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title\">Client<\/span>\n{\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">static<\/span> <span class=\"hljs-keyword\">void<\/span> <span class=\"hljs-title\">Main<\/span>(<span class=\"hljs-params\"><\/span>)<\/span>\n    {\n        <span class=\"hljs-keyword\">var<\/span> builder = <span class=\"hljs-keyword\">new<\/span> ConcreteBuilder();\n        \n        <span class=\"hljs-keyword\">var<\/span> director = <span class=\"hljs-keyword\">new<\/span> Director(builder);\n        director.Construct();\n\n        <span class=\"hljs-keyword\">var<\/span> product = builder.GetProduct();\n        WriteLine(<span class=\"hljs-string\">$\"Product Parts: <span class=\"hljs-subst\">{product.PartA}<\/span>, <span class=\"hljs-subst\">{product.PartB}<\/span>\"<\/span>);\n    }\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-7\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">C#<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">cs<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\">Summary<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Use the Builder pattern to simplify the construction of complex objects and makes the code more flexible and maintainable.<\/li>\n<\/ul>\n<div class=\"helpful-block-content\" data-title=\"\">\n\t<header>\n\t\t<div class=\"wth-question\">Was this tutorial helpful ?<\/div>\n\t\t<div 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