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C# Pair 类（开发人员如何使用）
发布 2024年六月6日
简介
数据对是一种简单的数据结构，用于保存两个相关的值。它为将两个不同的数据捆绑在一起提供了一种方便的方法。当一个方法需要返回两个值或处理键值关联时，通常会使用数据对。
在 C# 中，开发人员经常使用元组 (元组<T1, T2>`) 来配对值。然而，元组是不可变的，其元素可通过 Item1 和 Item2 等属性进行访问，这可能导致大量使用时代码的可读性降低。这时，自定义 Pair 类就派上用场了。
如果你需要一个结构来容纳两个相关的对象，而数据隐藏又不是首要任务，那么你就可以在代码中使用 Pair 类。Pair 类并不封装其对象引用。相反，它将对象引用作为公共类字段直接暴露给所有调用代码。
这种设计选择允许直接访问所包含的对象，而不需要封装的开销。此外，在文章的最后，我们将探讨如何 IronPDF 从 铁软件 可用于生成 PDF 文档。
元组
C# 7.0 引入了对元组语法的改进，使元组更易于使用。下面介绍如何声明和初始化元组：
// Tuple declaration
var person = (name: "John", age: 30);
// Accessing tuple elements
Console.WriteLine($"Name: {person.name}, Age: {person.age}");
// Tuple deconstruction
var (name, age) = person;
Console.WriteLine($"Name: {name}, Age: {age}");// Tuple declaration
var person = (name: "John", age: 30);
// Accessing tuple elements
Console.WriteLine($"Name: {person.name}, Age: {person.age}");
// Tuple deconstruction
var (name, age) = person;
Console.WriteLine($"Name: {name}, Age: {age}");' Tuple declaration
Dim person = (name:= "John", age:= 30)
' Accessing tuple elements
Console.WriteLine($"Name: {person.name}, Age: {person.age}")
' Tuple deconstruction
'INSTANT VB TODO TASK: VB has no equivalent to C# deconstruction declarations:
var(name, age) = person
Console.WriteLine($"Name: {name}, Age: {age}")VB C#
效益元组
简明语法
元组允许您使用简洁的语法表达复杂的数据结构，而无需定义自定义类或结构体。
重量轻
元组是一种轻量级数据结构，适用于需要临时或中间存储数据的情况。
隐式命名
使用元组语法，您可以隐式命名元组元素，从而提高代码的可读性并减少注释的需要。
从方法中返回多个值
public (int, int) Divide(int dividend, int divisor)
{
int quotient = dividend / divisor;
int remainder = dividend % divisor;
return (quotient, remainder);
}
var result = Divide(10, 3);
Console.WriteLine($"Quotient: {result.Item1}, Remainder: {result.Item2}");public (int, int) Divide(int dividend, int divisor)
{
int quotient = dividend / divisor;
int remainder = dividend % divisor;
return (quotient, remainder);
}
var result = Divide(10, 3);
Console.WriteLine($"Quotient: {result.Item1}, Remainder: {result.Item2}");Public Function Divide(ByVal dividend As Integer, ByVal divisor As Integer) As (Integer, Integer)
Dim quotient As Integer = dividend \ divisor
Dim remainder As Integer = dividend Mod divisor
Return (quotient, remainder)
End Function
Private result = Divide(10, 3)
Console.WriteLine($"Quotient: {result.Item1}, Remainder: {result.Item2}")VB C#
简化方法签名
public (string, string) GetNameAndSurname()
{
// Retrieve name and surname from a data source
return ("John", "Doe");
}
var (name, surname) = GetNameAndSurname();
Console.WriteLine($"Name: {name}, Surname: {surname}");public (string, string) GetNameAndSurname()
{
// Retrieve name and surname from a data source
return ("John", "Doe");
}
var (name, surname) = GetNameAndSurname();
Console.WriteLine($"Name: {name}, Surname: {surname}");Public Function GetNameAndSurname() As (String, String)
' Retrieve name and surname from a data source
Return ("John", "Doe")
End Function
'INSTANT VB TODO TASK: VB has no equivalent to C# deconstruction declarations:
var(name, surname) = GetNameAndSurname()
Console.WriteLine($"Name: {name}, Surname: {surname}")VB C#
分组相关数据
var point = (x: 10, y: 20);
var color = (r: 255, g: 0, b: 0);
var person = (name: "Alice", age: 25);var point = (x: 10, y: 20);
var color = (r: 255, g: 0, b: 0);
var person = (name: "Alice", age: 25);Dim point = (x:= 10, y:= 20)
Dim color = (r:= 255, g:= 0, b:= 0)
Dim person = (name:= "Alice", age:= 25)VB C#
限制和考虑因素
虽然 C# 7.0 元组具有显著的优势，但也有一些限制和注意事项需要牢记：
- 与自定义类或结构体相比，元组的表达能力有限。
- 如果不提供明确的名称，则使用 Item1、Item2 等来访问元组元素，这会降低代码的可读性。
配对自定义类
public class Pair<T1, T2>
{
public T1 First { get; set; }
public T2 Second { get; set; }
public Pair(T1 first, T2 second)
{
First = first;
Second = second;
}
}public class Pair<T1, T2>
{
public T1 First { get; set; }
public T2 Second { get; set; }
public Pair(T1 first, T2 second)
{
First = first;
Second = second;
}
}Public Class Pair(Of T1, T2)
Public Property First() As T1
Public Property Second() As T2
Public Sub New(ByVal first As T1, ByVal second As T2)
Me.First = first
Me.Second = second
End Sub
End ClassVB C#
这里的类型是在使用时定义的，两个属性是作为公共痛苦属性公开的
使用配对类
现在，让我们在下面的示例中探讨一下 Pair 类的一些常见用例：
1.存储坐标
Pair<int, int> coordinates = new Pair<int, int>(10, 20); // new instance
Console.WriteLine($"X: {coordinates.First}, Y: {coordinates.Second}");Pair<int, int> coordinates = new Pair<int, int>(10, 20); // new instance
Console.WriteLine($"X: {coordinates.First}, Y: {coordinates.Second}");Dim coordinates As New Pair(Of Integer, Integer)(10, 20) ' new instance
Console.WriteLine($"X: {coordinates.First}, Y: {coordinates.Second}")VB C#
2.从方法中返回多个值
public Pair<int, int> Divide(int dividend, int divisor)
{
int quotient = dividend / divisor;
int remainder = dividend % divisor;
return new Pair<int, int>(quotient, remainder);
}
Pair<int, int> result = Divide(10, 3);
Console.WriteLine($"Quotient: {result.First}, Remainder: {result.Second}");public Pair<int, int> Divide(int dividend, int divisor)
{
int quotient = dividend / divisor;
int remainder = dividend % divisor;
return new Pair<int, int>(quotient, remainder);
}
Pair<int, int> result = Divide(10, 3);
Console.WriteLine($"Quotient: {result.First}, Remainder: {result.Second}");Public Function Divide(ByVal dividend As Integer, ByVal divisor As Integer) As Pair(Of Integer, Integer)
Dim quotient As Integer = dividend \ divisor
Dim remainder As Integer = dividend Mod divisor
Return New Pair(Of Integer, Integer)(quotient, remainder)
End Function
Private result As Pair(Of Integer, Integer) = Divide(10, 3)
Console.WriteLine($"Quotient: {result.First}, Remainder: {result.Second}")VB C#
3.存储键值对
Pair<string, int> keyValue = new Pair<string, int>("Age", 30);
Console.WriteLine($"Key: {keyValue.First}, Value: {keyValue.Second}");Pair<string, int> keyValue = new Pair<string, int>("Age", 30);
Console.WriteLine($"Key: {keyValue.First}, Value: {keyValue.Second}");Dim keyValue As New Pair(Of String, Integer)("Age", 30)
Console.WriteLine($"Key: {keyValue.First}, Value: {keyValue.Second}")VB C#
键值对
键值对提供了一种简单高效的数据关联方式。在 C# 中，处理键值对的主要工具是 Dictionary<TKey, TValue> 类，它是一种用途广泛、功能强大的集合类型
了解键值对
键值对是一种将唯一的键与值关联起来的数据结构。这种关联允许根据数据的唯一标识符对数据进行有效检索和操作。在 C# 中，键值对通常用于缓存、配置管理和数据存储等任务。
Dictionary<TKey, TValue> in C&num；
C# 中的 Dictionary<TKey, TValue> 类是存储键值对的通用集合。它提供基于键的快速查找，广泛用于管理关联数据。
创建和填充字典
Dictionary<string, int> ages = new Dictionary<string, int>();
ages["Alice"] = 30;
ages["Bob"] = 35;
ages["Charlie"] = 25;Dictionary<string, int> ages = new Dictionary<string, int>();
ages["Alice"] = 30;
ages["Bob"] = 35;
ages["Charlie"] = 25;Dim ages As New Dictionary(Of String, Integer)()
ages("Alice") = 30
ages("Bob") = 35
ages("Charlie") = 25VB C#
按键访问值
Console.WriteLine($"Alice's age: {ages["Alice"]}");Console.WriteLine($"Alice's age: {ages["Alice"]}");Console.WriteLine($"Alice's age: {ages("Alice")}")VB C#
键值对迭代
foreach (var pair in ages)
{
Console.WriteLine($"Name: {pair.Key}, Age: {pair.Value}");
}foreach (var pair in ages)
{
Console.WriteLine($"Name: {pair.Key}, Age: {pair.Value}");
}For Each pair In ages
Console.WriteLine($"Name: {pair.Key}, Age: {pair.Value}")
Next pairVB C#
高级场景
处理丢失的密钥
if (ages.TryGetValue("David", out int age))
{
Console.WriteLine($"David's age: {age}");
}
else
{
Console.WriteLine("David's age is not available.");
}if (ages.TryGetValue("David", out int age))
{
Console.WriteLine($"David's age: {age}");
}
else
{
Console.WriteLine("David's age is not available.");
}Dim age As Integer
If ages.TryGetValue("David", age) Then
Console.WriteLine($"David's age: {age}")
Else
Console.WriteLine("David's age is not available.")
End IfVB C#
删除条目
ages.Remove("Charlie");ages.Remove("Charlie");ages.Remove("Charlie")VB C#
字典初始化
var colors = new Dictionary<string, string>
{
{ "red", "#FF0000" },
{ "green", "#00FF00" },
{ "blue", "#0000FF" }
};var colors = new Dictionary<string, string>
{
{ "red", "#FF0000" },
{ "green", "#00FF00" },
{ "blue", "#0000FF" }
};Dim colors = New Dictionary(Of String, String) From {
{"red", "#FF0000"},
{"green", "#00FF00"},
{"blue", "#0000FF"}
}VB C#
词典之外：替代方案和考虑因素
虽然 "Dictionary<TKey, TValue>"是一个功能强大的工具，但其他方法和考虑因素取决于应用程序的具体要求：
- ConcurrentDictionary<TKey,TValue>:`如果您的应用程序需要多个线程对字典进行线程安全访问，请考虑使用 ConcurrentDictionary<TKey,TValue>。
ImmutableDictionary<TKey,TValue>:
对于需要不可变性的场景，System.Collections.Immutable命名空间中的ImmutableDictionary<TKey, TValue>` 提供了不可变的键值集合。- 自定义键值对类：在需要额外功能或特定行为的情况下，可考虑根据自己的要求创建自定义键值对类。
IronPDF 图书馆
IronPDF 从 铁软件 是一个用于生成 PDF 文档的优秀库。其易用性和高效性首屈一指。
IronPDF 可通过 NuGet 软件包管理器安装：
Install-Package IronPdf
或者从 Visual Studio 这样做：
要生成带有元组示例的文档，我们可以使用以下代码：
namespace IronPatterns;
class Program
{
static void Main()
{
Console.WriteLine("-----------Iron Software-------------");
var renderer = new ChromePdfRenderer(); // var pattern
var content = " <h1> Iron Software is Awesome </h1> Made with IronPDF!";
content += "<h2>Demo C# Pair with Tuples</h2>";
var result = Divide(10, 3);
Console.WriteLine($"Quotient: {result.Item1}, Remainder: {result.Item2}");
content += $"<p>When we divide 10, 3 </p>";
content += $"<p>Quotient: {result.Item1}, Remainder: {result.Item2}</p>";
var pdf = renderer.RenderHtmlAsPdf(content);
pdf.SaveAs("output.pdf"); // Saves PDF
}
public static (int, int) Divide(int dividend, int divisor)
{
// var count;
int quotient = dividend / divisor;
int remainder = dividend % divisor;
return (quotient, remainder);
}
}namespace IronPatterns;
class Program
{
static void Main()
{
Console.WriteLine("-----------Iron Software-------------");
var renderer = new ChromePdfRenderer(); // var pattern
var content = " <h1> Iron Software is Awesome </h1> Made with IronPDF!";
content += "<h2>Demo C# Pair with Tuples</h2>";
var result = Divide(10, 3);
Console.WriteLine($"Quotient: {result.Item1}, Remainder: {result.Item2}");
content += $"<p>When we divide 10, 3 </p>";
content += $"<p>Quotient: {result.Item1}, Remainder: {result.Item2}</p>";
var pdf = renderer.RenderHtmlAsPdf(content);
pdf.SaveAs("output.pdf"); // Saves PDF
}
public static (int, int) Divide(int dividend, int divisor)
{
// var count;
int quotient = dividend / divisor;
int remainder = dividend % divisor;
return (quotient, remainder);
}
}Namespace IronPatterns
Friend Class Program
Shared Sub Main()
Console.WriteLine("-----------Iron Software-------------")
Dim renderer = New ChromePdfRenderer() ' var pattern
Dim content = " <h1> Iron Software is Awesome </h1> Made with IronPDF!"
content &= "<h2>Demo C# Pair with Tuples</h2>"
Dim result = Divide(10, 3)
Console.WriteLine($"Quotient: {result.Item1}, Remainder: {result.Item2}")
content &= $"<p>When we divide 10, 3 </p>"
content &= $"<p>Quotient: {result.Item1}, Remainder: {result.Item2}</p>"
Dim pdf = renderer.RenderHtmlAsPdf(content)
pdf.SaveAs("output.pdf") ' Saves PDF
End Sub
Public Shared Function Divide(ByVal dividend As Integer, ByVal divisor As Integer) As (Integer, Integer)
' var count;
Dim quotient As Integer = dividend \ divisor
Dim remainder As Integer = dividend Mod divisor
Return (quotient, remainder)
End Function
End Class
End NamespaceVB C#
输出
IronPDF 试用许可证
IronPDF.将许可证放入 appsettings.json 中。
"IronPDF.LicenseKey": "<Your Key>""IronPDF.LicenseKey": "<Your Key>"'INSTANT VB TODO TASK: The following line uses invalid syntax:
'"IronPDF.LicenseKey": "<Your Key>"VB C#
结论
在本文中，我们探讨了成对的概念以及在 C# 中使用 Pair 类的重要性。我们提供了一个 Pair 自定义类的简单实现以及各种用例，展示了它在日常编程任务中的多功能性和实用性。
无论您是在处理坐标、从一个方法返回多个值，还是在存储键值关联，Pair 类都是您编程技能集的重要补充。
除此以外 IronPDF 该库是开发人员在应用程序中根据需要即时生成 PDF 文档的重要组合技能。
