使用 LINQ 实现 IEnumerable 接口的 C# 程序

LINQ 被称为语言集成查询，它是在 .NET 3.5 中引入的。它使 .NET 语言能够生成查询以从数据源中检索数据。它消除了编程语言和数据库之间的不匹配，并且无论使用哪种类型的数据源，用于创建查询的语法都是相同的。在本文中，我们将使用 LINQ 实现一个 IEnumerable 接口。此接口用于迭代列表、堆栈、队列等集合。或者我们可以说此接口是所有可以枚举的非泛型集合的基本接口。

句法：

IEnumerable

使用 IEnumerable，我们将显示名称以“D”开头的员工数据。

示例：

Input : List of Employees:
        {{id = 201, name = "Druva", age = 12},
         {id = 202, name = "Deepu", age = 15},
         {id = 203, name = "Manoja", age = 13},
         {id = 204, name = "Sathwik", age = 12},
         {id = 205, name = "Suraj", age = 15}}
Output : {{id = 201, name = "Druva", age = 12},
          {id = 202, name = "Deepu", age = 15}}
 
Input : List of Employees:
        {{id = 301, name = "Sathwik", age = 12},
         {id = 302, name = "Saran", age = 15}}
Output : No Output

方法：

To find the list of employees whose name starts with letter ‘D’ follow the following steps:

Create a list of employees with four variables(Id, name, department, and salary).
Iterate through the employee details by using Where() function and get the employee details by choosing employee whose name starts with ‘D’ using s => s.name[0] == ‘D’.
Now call the ToString() method.
Display the employee details.

编程需要懂一点英语

例子：

C#

// C# program to display the details of those 
// employees whose name starts with character "D"
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
  
class Employee{
      
// Declare 4 variables - id, name, 
// department, and salary
int id; 
int salary;
string name;
string department;
  
// Get the to string method that returns 
// id, name, department, and salary
public override string ToString()
{
    return id + " " + name + " " + 
       salary + " " + department;
}
  
// Driver code
static void Main(string[] args)
{
      
    // Declare a list variable 
    List emp = new List()
    {
          
        // Create 5 Employee details
        new Employee{ id = 201, name = "Druva", 
                      salary = 12000, department = "HR" },
        new Employee{ id = 202, name = "Deepu", 
                      salary = 15000, department = "Development" },
        new Employee{ id = 203, name = "Manoja", 
                      salary = 13000, department = "HR" },
        new Employee{ id = 204, name = "Sathwik", 
                      salary = 12000, department = "Designing" },
        new Employee{ id = 205, name = "Suraj", 
                      salary = 15000, department = "Development" }
    };
      
    // Iterate the Employee by selecting Employee 
    // name starts with D
    // Using IEnumerable interface
    IEnumerable result = emp.Where(x => x.name[0] == 'D');
      
    // Display employee details
    Console.WriteLine("ID  Name  Salary  Department");
    Console.WriteLine("++++++++++++++++++++++++++++");
    foreach (Employee e in result)
    {
          
        // Call the to string method
        Console.WriteLine(e.ToString());
    }    
}
}

输出：

ID  Name  Salary  Department
++++++++++++++++++++++++++++
201 Druva 12000 HR
202 Deepu 15000 Development