演示在 LINQ 中将方法用作条件的 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，我们将以员工数据中的员工姓名包含少于四个字符的员工数据为例，演示如何使用该方法作为条件。所以对于这个任务，我们使用 Where()函数。此函数根据给定条件过滤给定数组。或者我们可以说 Where() 方法根据指定的条件从序列中返回值。

例子：

Input  : [("m"), ("srav"), ("a"), ("gopi"), ("bai")("sai")]
Output : [("m"), ("a"), ("bai"), ("sai")]
 
Input  : [("bobby"), ("ramya"), ("sairam")]
Output : No Output

方法

To print the list of employees whose name contains less than 4 characters follow the following steps:

1. Create a function named “checkstring” which check the length of the string is less than 4 characters.i.e.,  str.Length < 4.
2. Create a list(i.e., XEmployee) that will contain the name of the employees.
3. Add the employee names to the list.
4. Now find the employee names whose length is less than 4 characters by using “data.Where(employee => checkstring(employee))”.
5. Display the employee names.

例子：

C#

// C# program to illustrate the use of
// the method as a condition in the
// LINQ where() method of the list collection
using System;
using System.Collections.Generic;
using System.Linq;
 
class GFG{
 
// Function to check the given string is less than 4
static bool checkstring(string str)
{
    if (str.Length < 4)
        return true;
    else
        return false;
}
 
static void Main(string[] args)
{
     
    // Define a list
    List XEmployee = new List();
     
    // Add names into the list
    XEmployee.Add("m");
    XEmployee.Add("srav");
    XEmployee.Add("a");
    XEmployee.Add("gopi");
    XEmployee.Add("bai");
    XEmployee.Add("sai");
 
    // Choose the employee whose name length is
    // less than 4 letters
    IEnumerable result = XEmployee.Where(
                                 employee => checkstring(employee));
 
    Console.WriteLine("Name of the Employees are: ");
     
    // Display employee names
    foreach (string stname in result)
    {
        Console.WriteLine(stname);
    }
}
}

输出：

Name of the Employees are: 
m
a
bai
sai