使用 Select Clause LINQ 显示学生详细信息的 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，我们将学习如何使用 LINQ 中的 select 子句打印学生列表及其详细信息。当我们想从给定的集合中选择一些特定的值时，使用 Select 子句。

句法：

 IEnumerable Query = from student in stu select student;

例子：

Input :
{ stu_id = 101, stu_name = "bobby", 
  stu_dept = "cse", stu_salary = 8900 },
{ stu_id = 102, stu_name = "sravan", 
  stu_dept = "ece", stu_salary = 8900 },
{ stu_id = 103, stu_name = "deepu", 
  stu_dept = "mba", stu_salary = 8900 }};
Output :
{ stu_id = 101, stu_name = "bobby", 
  stu_dept = "cse", stu_salary = 8900 },
{ stu_id = 102, stu_name = "sravan", 
  stu_dept = "ece", stu_salary = 8900 },
{ stu_id = 103, stu_name = "deepu", 
  stu_dept = "mba", stu_salary = 8900 }};
  
Input :
{ stu_id = 101, stu_name = "bobby", 
  stu_dept = "cse", stu_salary = 8900 }
Output:
{ stu_id = 101, stu_name = "bobby", 
  stu_dept = "cse", stu_salary = 8900 }
                        

方法

To display the list of students follow the following steps:

1. Create a list of students with four variables(Id, name department and semester).
2. Iterate through the student details by using for loop and get the student details by using select clause
3. Display the student details.

例子 ：

C#

// C# program to print the list of students
// details using select clause
  
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
  
class Student{
      
// Declare 4 variables - id, age, department and semester
int stu_id; 
string stu_dept;
string stu_name;
int stu_semester;
  
// Get the to string method that returns
// id, age, department and semester
public override string ToString()
{
    return stu_id + " " + stu_name + " " + 
           stu_dept + " " + stu_semester;
}
  
// Driver code
static void Main(string[] args)
{
      
    // Declare a list variable 
    List stu = new List()
    {
          
        // Create 3 Student details
        new Student{ stu_id = 101, stu_name = "bobby", 
                     stu_dept = "CSE", stu_semester = 2 },
        new Student{ stu_id = 102, stu_name = "sravan", 
                     stu_dept = "ECE", stu_semester = 1 },
        new Student{ stu_id = 103, stu_name = "deepu", 
                     stu_dept = "EEE", stu_semester = 4},
    };
      
    // Iterate the Employee 
    // using select function
    IEnumerable Query = from student in stu select student;
      
    // Display student details
    Console.WriteLine("ID  Name  Department Semester");
    Console.WriteLine("+++++++++++++++++++++++++++");
    foreach (Student e in Query)
    {
          
        // Call the to string method
        Console.WriteLine(e.ToString());
    }
}
}

输出：

ID  Name  Department Semester
+++++++++++++++++++++++++++
101 bobby CSE 2
102 sravan ECE 1
103 deepu EEE 4