在ef核心中使用OR条件基于所有可选参数的动态查询

using Microsoft.EntityFrameworkCore;
using System;
using System.Linq;
using System.Linq.Expressions;

public class MyEntity
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int Age { get; set; }
    // 其他属性...
}

public class MyDbContext : DbContext
{
    public DbSet<MyEntity> MyEntities { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer("your_connection_string");
    }
}

public class MyRepository
{
    private readonly MyDbContext _dbContext;

    public MyRepository(MyDbContext dbContext)
    {
        _dbContext = dbContext;
    }

    public IQueryable<MyEntity> GetEntities(string name, int? age)
    {
        IQueryable<MyEntity> query = _dbContext.MyEntities;

        if (!string.IsNullOrEmpty(name))
        {
            query = query.Where(e => e.Name.Contains(name));
        }

        if (age.HasValue)
        {
            query = query.Where(e => e.Age == age.Value);
        }

        return query;
    }
}

public class Program
{
    public static void Main()
    {
        using (var dbContext = new MyDbContext())
        {
            var repository = new MyRepository(dbContext);

            // 示例查询
            var entities = repository.GetEntities("John", 25).ToList();
            // 根据参数动态构建查询条件，查询名字包含"John"且年龄为25的实体

            foreach (var entity in entities)
            {
                Console.WriteLine($"Id: {entity.Id}, Name: {entity.Name}, Age: {entity.Age}");
            }
        }
    }
}