C#linq与表达式

我是c#新手，在理解给定的问题陈述时遇到问题。 问题陈述： 编写一个程序，查找特定年份之间发布的车辆

已提供车辆等级，供您参考

类程序包含一个硬编码列表，在“vehicleList”属性中包含车辆信息

a） 实现方法“getVehicleName”

public static void getVehicleName（int fromYear，int toYear）//方法签名

此方法必须显示fromYear和toYear（包括这些年份）之间发布的车辆名称（来自给定列表）。使用LINQ概念

b） 实现方法“Main”

从用户处获取from year和to year。将其传递给“getVehicleName”方法

注意：不需要在Main中调用“getMyExpression”方法

c） 实现方法“getMyExpression”

公共静态表达式getMyExpression（int fromYear，int toYear）

已经为您提供了此方法片段。此方法用于测试LINQ查询表达式或LINQ方法扩展。因此，请在提供的空格中填写查询表达式或方法扩展名。仅查询表达式或方法扩展名。在这个类中不需要实现更多的东西

可能继承列表 将方法

getVehicleName

实现为linq查询

public string getVehicleName => this.FirstOrDefault(o => ...

---

看来你就快到了：

from v in vehicle 
where v.ReleaseYear >= fromYear && v.ReleaseYear <= toYear 
select v.VehicleName

来自车辆中的v
其中v.ReleaseYear>=fromYear&&v.ReleaseYear v.ReleaseYear>=fromYear&&v.ReleaseYear n.VehicleName）

来自车辆列表中的v，其中v.ReleaseYear>=来自年份和&v.ReleaseYear在实现getVehicleName时使用：

from v in Vehicle列出其中v.ReleaseYear>=fromYear和v.ReleaseYear s.ReleaseYear>=fromYear和s.ReleaseYearVehicle.cs

public class Vehicle          
{
    public String VehicleId{get; set; }
    public String VehicleName{ get; set; }
    public String Brand { get; set; }
    public int ReleaseYear { get; set; }

    public Vehicle(String vehicleId, String vehicleName, String brand,int releaseYear)
    {
        this.VehicleId = vehicleId;
        this.VehicleName = vehicleName;
        this.Brand = brand;
        this.ReleaseYear = releaseYear;
    }
    
}

    static void Main(string[] args)   
    {
        
        
        Console.WriteLine("Enter From Year :");
        int fromYear = int.Parse(Console.ReadLine());
        Console.WriteLine("Enter To Year :");
        int toYear = int.Parse(Console.ReadLine());
        GetVehicleName(fromYear,toYear);
     
        
        
    }
    public static void GetVehicleName(int fromYear , int toYear){
        var resultQuery = from v in VehicleList where v.ReleaseYear >= fromYear && v.ReleaseYear <= toYear orderby v.ReleaseYear select v;
        Console.WriteLine($"Vehicle Name Released Between {fromYear} And {toYear} :");
        foreach (Vehicle s in resultQuery)
        {
            Console.WriteLine(s.VehicleName);

        }
        Console.ReadKey();
        
        
    }
    public static ParameterExpression variableExpr = Expression.Variable(typeof(IEnumerable<Vehicle>), "sampleVar");
    
    public static Expression GetMyExpression(int fromYear, int toYear)
    {  
        
        Expression assignExpr = Expression.Assign(variableExpr, Expression.Constant(from v in VehicleList where v.ReleaseYear >= fromYear && v.ReleaseYear <= toYear orderby v.ReleaseYear select v));
        return assignExpr;
    }

Program.cs

public class Vehicle          
{
    public String VehicleId{get; set; }
    public String VehicleName{ get; set; }
    public String Brand { get; set; }
    public int ReleaseYear { get; set; }

    public Vehicle(String vehicleId, String vehicleName, String brand,int releaseYear)
    {
        this.VehicleId = vehicleId;
        this.VehicleName = vehicleName;
        this.Brand = brand;
        this.ReleaseYear = releaseYear;
    }
    
}

    static void Main(string[] args)   
    {
        
        
        Console.WriteLine("Enter From Year :");
        int fromYear = int.Parse(Console.ReadLine());
        Console.WriteLine("Enter To Year :");
        int toYear = int.Parse(Console.ReadLine());
        GetVehicleName(fromYear,toYear);
     
        
        
    }
    public static void GetVehicleName(int fromYear , int toYear){
        var resultQuery = from v in VehicleList where v.ReleaseYear >= fromYear && v.ReleaseYear <= toYear orderby v.ReleaseYear select v;
        Console.WriteLine($"Vehicle Name Released Between {fromYear} And {toYear} :");
        foreach (Vehicle s in resultQuery)
        {
            Console.WriteLine(s.VehicleName);

        }
        Console.ReadKey();
        
        
    }
    public static ParameterExpression variableExpr = Expression.Variable(typeof(IEnumerable<Vehicle>), "sampleVar");
    
    public static Expression GetMyExpression(int fromYear, int toYear)
    {  
        
        Expression assignExpr = Expression.Assign(variableExpr, Expression.Constant(from v in VehicleList where v.ReleaseYear >= fromYear && v.ReleaseYear <= toYear orderby v.ReleaseYear select v));
        return assignExpr;
    }

static void Main（字符串[]args）
{
Console.WriteLine（“输入起始年份：”）；
int fromYear=int.Parse（Console.ReadLine（））；
Console.WriteLine（“输入年份：”；
int toYear=int.Parse（Console.ReadLine（））；
GetVehicleName（fromYear，toYear）；
}
公共静态无效GetVehicleName（int fromYear，int toYear）{
var resultQuery=from v in vehicle列表，其中v.ReleaseYear>=fromYear&&v.ReleaseYear=fromYear&&v.ReleaseYear请以文本形式包含代码，而不是图像。并非所有内容都是如此，因此访问者将跟踪图像链接，有些人由于公司防火墙的原因无法跟踪。文本还允许人们复制/粘贴，以防他们需要进行自己的测试，并使其成为现实archable.Text降低了向您提供帮助的障碍。getMyExpression
的作用是什么？虽然此代码可能有助于回答问题，但最好包含一些上下文，解释它是如何工作的以及何时使用它。从长远来看，仅代码的答案往往不太有用。有关更多信息，请参阅。虽然此代码可以回答问题，但专业人士提供关于此代码为什么和/或如何回答此问题的其他上下文可提高其长期价值。
public class Vehicle          
{
    public String VehicleId{get; set; }
    public String VehicleName{ get; set; }
    public String Brand { get; set; }
    public int ReleaseYear { get; set; }

    public Vehicle(String vehicleId, String vehicleName, String brand,int releaseYear)
    {
        this.VehicleId = vehicleId;
        this.VehicleName = vehicleName;
        this.Brand = brand;
        this.ReleaseYear = releaseYear;
    }
    
}

    static void Main(string[] args)   
    {
        
        
        Console.WriteLine("Enter From Year :");
        int fromYear = int.Parse(Console.ReadLine());
        Console.WriteLine("Enter To Year :");
        int toYear = int.Parse(Console.ReadLine());
        GetVehicleName(fromYear,toYear);
     
        
        
    }
    public static void GetVehicleName(int fromYear , int toYear){
        var resultQuery = from v in VehicleList where v.ReleaseYear >= fromYear && v.ReleaseYear <= toYear orderby v.ReleaseYear select v;
        Console.WriteLine($"Vehicle Name Released Between {fromYear} And {toYear} :");
        foreach (Vehicle s in resultQuery)
        {
            Console.WriteLine(s.VehicleName);

        }
        Console.ReadKey();
        
        
    }
    public static ParameterExpression variableExpr = Expression.Variable(typeof(IEnumerable<Vehicle>), "sampleVar");
    
    public static Expression GetMyExpression(int fromYear, int toYear)
    {  
        
        Expression assignExpr = Expression.Assign(variableExpr, Expression.Constant(from v in VehicleList where v.ReleaseYear >= fromYear && v.ReleaseYear <= toYear orderby v.ReleaseYear select v));
        return assignExpr;
    }