我之所以提出这个问题，是因为我们在实体框架6中有超过100个SqlQuery的无实体使用实例，所以按照微软建议的方式在我们的例子中并不容易工作。

此外，在从EF迁移到EFC的过程中，我们不得不维持一个EF(实体框架6)/ EFC(实体框架核心5)代码库好几个月。代码库相当大，根本不可能“一夜之间”迁移。

下面的答案是基于上面的答案，这只是一个小的扩展，使它们适用于更多的边缘情况。

首先，对于每个基于EF的项目，我们创建了一个基于EFC的项目(例如MyProject)。csproj ==> MyProject_EFC.csproj)，在所有这样的EFC项目中我们定义了常量EFCORE。如果你正在做一个快速的一次性迁移从EF到EFC，那么你不需要，你可以保持什么里面# If EFCORE…删除#else里面的内容# endif下面。

下面是主要的互操作扩展类。

using System;
using System.Collections.Generic;
using System.Threading;

#if EFCORE
using System.ComponentModel.DataAnnotations.Schema;
using System.Data;
using System.Data.Common;
using System.Linq;
using System.Reflection;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.ChangeTracking;
using Microsoft.EntityFrameworkCore.Storage;
using Database = Microsoft.EntityFrameworkCore.Infrastructure.DatabaseFacade;
using MoreLinq.Extensions;
#else
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
#endif

namespace YourNameSpace.EntityFrameworkCore
{
    /// <summary>
    /// Collection of extension methods to simplify migration from EF to EFC.
    /// </summary>
    public static class EntityFrameworkCoreInterop
    {
        /// <summary>
        /// https://stackoverflow.com/questions/6637679/reflection-get-attribute-name-and-value-on-property
        /// </summary>
        public static TAttribute? TryGetAttribute<TAttribute>(this PropertyInfo prop) where TAttribute : Attribute =>
            prop.GetCustomAttributes(true).TryGetAttribute<TAttribute>();

        public static TAttribute? TryGetAttribute<TAttribute>(this Type t) where TAttribute : Attribute =>
            t.GetCustomAttributes(true).TryGetAttribute<TAttribute>();

        public static TAttribute? TryGetAttribute<TAttribute>(this IEnumerable<object> attrs) where TAttribute : Attribute
        {
            foreach (object attr in attrs)
            {
                switch (attr)
                {
                    case TAttribute t:
                    {
                        return t;
                    }
                }
            }

            return null;
        }

        /// <summary>
        /// Returns true if the source string matches *any* of the passed-in strings (case insensitive)
        /// </summary>
        public static bool EqualsNoCase(this string? s, params string?[]? targets)
        {
            if (s == null && (targets == null || targets.Length == 0))
            {
                return true;
            }

            if (targets == null)
            {
                return false;
            }

            return targets.Any(t => string.Equals(s, t, StringComparison.OrdinalIgnoreCase));
        }

#if EFCORE
        public class EntityException : Exception
        {
            public EntityException(string message) : base(message)
            {
            }
        }

        public static TEntity GetEntity<TEntity>(this EntityEntry<TEntity> entityEntry)
            where TEntity : class => entityEntry.Entity;

        #region SqlQuery Interop

        /// <summary>
        /// kk:20210727 - This is a little bit ugly but given that this interop method is used just once,
        /// it is not worth spending more time on it.
        /// </summary>
        public static List<T> ToList<T>(this IOrderedAsyncEnumerable<T> e) =>
            Task.Run(() => e.ToListAsync().AsTask()).GetAwaiter().GetResult();

        private static string GetColumnName(this MemberInfo info) =>
            info.GetCustomAttributes().TryGetAttribute<ColumnAttribute>()?.Name ?? info.Name;

        /// <summary>
        /// See: https://stackoverflow.com/questions/35631903/raw-sql-query-without-dbset-entity-framework-core
        /// Executes raw query with parameters and maps returned values to column property names of Model provided.
        /// Not all properties are required to be present in the model. If not present then they will be set to nulls.
        /// </summary>
        private static async IAsyncEnumerable<T> ExecuteQuery<T>(this Database database, string query, params object[] parameters)
        {
            await using DbCommand command = database.GetDbConnection().CreateCommand();
            command.CommandText = query;
            command.CommandType = CommandType.Text;

            if (database.CurrentTransaction != null)
            {
                command.Transaction = database.CurrentTransaction.GetDbTransaction();
            }

            foreach (var parameter in parameters)
            {
                // They are supposed to be of SqlParameter type but are passed as objects.
                command.Parameters.Add(parameter);
            }

            await database.OpenConnectionAsync();
            await using DbDataReader reader = await command.ExecuteReaderAsync();
            var t = typeof(T);

            // TODO kk:20210825 - I do know that the code below works as we use it in some other place where it does work.
            // However, I am not 100% sure that R# proposed version does. Check and refactor when time permits.
            //
            // ReSharper disable once CheckForReferenceEqualityInstead.1
            if (t.IsGenericType && t.GetGenericTypeDefinition().Equals(typeof(Nullable<>)))
            {
                t = Nullable.GetUnderlyingType(t)!;
            }

            var lstColumns = t
                .GetProperties(BindingFlags.DeclaredOnly | BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
                .ToList();

            while (await reader.ReadAsync())
            {
                if (t.IsPrimitive || t == typeof(string) || t == typeof(DateTime) || t == typeof(Guid) || t == typeof(decimal))
                {
                    var val = await reader.IsDBNullAsync(0) ? null : reader[0];
                    yield return (T) val!;
                }
                else
                {
                    var newObject = Activator.CreateInstance<T>();

                    for (var i = 0; i < reader.FieldCount; i++)
                    {
                        var name = reader.GetName(i);
                        var val = await reader.IsDBNullAsync(i) ? null : reader[i];
                        var prop = lstColumns.FirstOrDefault(a => a.GetColumnName().EqualsNoCase(name));

                        if (prop == null)
                        {
                            continue;
                        }

                        prop.SetValue(newObject, val, null);
                    }

                    yield return newObject;
                }
            }
        }

        #endregion

        public static DbRawSqlQuery<TElement> SqlQuery<TElement>(this Database database, string sql, params object[] parameters) =>
            new(database, sql, parameters);

        public class DbRawSqlQuery<TElement> : IAsyncEnumerable<TElement>
        {
            private readonly IAsyncEnumerable<TElement> _elements;

            internal DbRawSqlQuery(Database database, string sql, params object[] parameters) =>
                _elements = ExecuteQuery<TElement>(database, sql, parameters);

            public IAsyncEnumerator<TElement> GetAsyncEnumerator(CancellationToken cancellationToken = new ()) =>
                _elements.GetAsyncEnumerator(cancellationToken);

            public async Task<TElement> SingleAsync() => await _elements.SingleAsync();
            public TElement Single() => Task.Run(SingleAsync).GetAwaiter().GetResult();
            public async Task<TElement> FirstAsync() => await _elements.FirstAsync();
            public TElement First() => Task.Run(FirstAsync).GetAwaiter().GetResult();
            public async Task<TElement?> SingleOrDefaultAsync() => await _elements.SingleOrDefaultAsync();
            public async Task<int> CountAsync() => await _elements.CountAsync();
            public async Task<List<TElement>> ToListAsync() => await _elements.ToListAsync();
            public List<TElement> ToList() => Task.Run(ToListAsync).GetAwaiter().GetResult();

        }
#endif
    }
}

用法与以前的EF用法没有区别:

public async Task<List<int>> GetMyResults()
{
    using var ctx = GetMyDbContext();
    const string sql = "select 1 as Result";
    return await ctx.GetDatabase().SqlQuery<int>(sql).ToListAsync();
}

其中GetMyDbContext是一个获取数据库上下文的方法，GetDatabase是一个返回((DbContext)上下文的一行互操作。给定IMyDbContext的数据库:DbContext。这是为了简化同时进行的EF / EFC操作。

这适用于基本类型(上面的例子)、实体、本地类(但不包括匿名类)。通过GetColumnName支持列重命名，但是，…上面已经做过了。

我更新了扩展方法从@AminRostami返回IAsyncEnumerable(这样LINQ过滤可以应用)，它的映射模型列名的记录从DB返回到模型(EF Core 5测试):

扩展本身:

public static class QueryHelper
{
    private static string GetColumnName(this MemberInfo info)
    {
        List<ColumnAttribute> list = info.GetCustomAttributes<ColumnAttribute>().ToList();
        return list.Count > 0 ? list.Single().Name : info.Name;
    }
    /// <summary>
    /// Executes raw query with parameters and maps returned values to column property names of Model provided.
    /// Not all properties are required to be present in model (if not present - null)
    /// </summary>
    public static async IAsyncEnumerable<T> ExecuteQuery<T>(
        [NotNull] this DbContext db,
        [NotNull] string query,
        [NotNull] params SqlParameter[] parameters)
        where T : class, new()
    {
        await using DbCommand command = db.Database.GetDbConnection().CreateCommand();
        command.CommandText = query;
        command.CommandType = CommandType.Text;
        if (parameters != null)
        {
            foreach (SqlParameter parameter in parameters)
            {
                command.Parameters.Add(parameter);
            }
        }
        await db.Database.OpenConnectionAsync();
        await using DbDataReader reader = await command.ExecuteReaderAsync();
        List<PropertyInfo> lstColumns = new T().GetType()
            .GetProperties(BindingFlags.DeclaredOnly | BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic).ToList();
        while (await reader.ReadAsync())
        {
            T newObject = new();
            for (int i = 0; i < reader.FieldCount; i++)
            {
                string name = reader.GetName(i);
                PropertyInfo prop = lstColumns.FirstOrDefault(a => a.GetColumnName().Equals(name));
                if (prop == null)
                {
                    continue;
                }
                object val = await reader.IsDBNullAsync(i) ? null : reader[i];
                prop.SetValue(newObject, val, null);
            }
            yield return newObject;
        }
    }
}

使用的模型(注意列名与实际的属性名不同):

public class School
{
    [Key] [Column("SCHOOL_ID")] public int SchoolId { get; set; }

    [Column("CLOSE_DATE", TypeName = "datetime")]
    public DateTime? CloseDate { get; set; }

    [Column("SCHOOL_ACTIVE")] public bool? SchoolActive { get; set; }
}

实际的用法:

public async Task<School> ActivateSchool(int schoolId)
{
    // note that we're intentionally not returning "SCHOOL_ACTIVE" with select statement
    // this might be because of certain IF condition where we return some other data
    return await _context.ExecuteQuery<School>(
        "UPDATE SCHOOL SET SCHOOL_ACTIVE = 1 WHERE SCHOOL_ID = @SchoolId; SELECT SCHOOL_ID, CLOSE_DATE FROM SCHOOL",
        new SqlParameter("@SchoolId", schoolId)
    ).SingleAsync();
}

实际上，您可以创建一个通用的存储库并做类似的事情

public class GenericRepository<TEntity> : IGenericRepository<TEntity> where TEntity : BaseEntity
{
    private readonly DataContext context;
    private readonly DbSet<TEntity> dbSet;

    public GenericRepository(DataContext context)
    {
        this.context = context;
        this.dbSet = context.Set<TEntity>();
    }

   
    public IEnumerable<TEntity> ExecuteCommandQuery(string command)
        => dbSet.FromSqlRaw(command);

}

你也可以使用QueryFirst。和Dapper一样，这完全不在EF的范围内。与Dapper(或EF)不同的是，您不需要维护POCO，只需在真实环境中编辑sql sql，并根据DB不断对其进行重新验证。免责声明:我是QueryFirst的作者。

在其他答案的基础上，我写了这个助手来完成这个任务，包括示例用法:

public static class Helper
{
    public static List<T> RawSqlQuery<T>(string query, Func<DbDataReader, T> map)
    {
        using (var context = new DbContext())
        {
            using (var command = context.Database.GetDbConnection().CreateCommand())
            {
                command.CommandText = query;
                command.CommandType = CommandType.Text;

                context.Database.OpenConnection();

                using (var result = command.ExecuteReader())
                {
                    var entities = new List<T>();

                    while (result.Read())
                    {
                        entities.Add(map(result));
                    }

                    return entities;
                }
            }
        }
    }

用法:

public class TopUser
{
    public string Name { get; set; }

    public int Count { get; set; }
}

var result = Helper.RawSqlQuery(
    "SELECT TOP 10 Name, COUNT(*) FROM Users U"
    + " INNER JOIN Signups S ON U.UserId = S.UserId"
    + " GROUP BY U.Name ORDER BY COUNT(*) DESC",
    x => new TopUser { Name = (string)x[0], Count = (int)x[1] });

result.ForEach(x => Console.WriteLine($"{x.Name,-25}{x.Count}"));

我计划在添加内置支持后尽快摆脱它。根据EF核心团队的Arthur Vickers的声明，这是2.0后的优先级。这个问题正在被追踪。

如果您使用EF Core 3.0或更新版本

你需要使用无键实体类型，以前称为查询类型:

该特性是在EF Core 2.1中以查询类型的名称添加的。 在EF Core 3.0中，这个概念被重命名为无键实体类型。的 [无键]数据注释在EFCore 5.0中可用。

要使用它们，你需要首先用[Keyless]数据注释标记你的类SomeModel，或者通过.HasNoKey()方法调用进行流畅配置，如下所示:

public DbSet<SomeModel> SomeModels { get; set; }

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<SomeModel>().HasNoKey();
}

配置完成后，可以使用这里解释的方法之一来执行SQL查询。例如，你可以用这个:

var result = context.SomeModels.FromSqlRaw("SQL SCRIPT").ToList();
var result = await context.SomeModels.FromSql("SQL_SCRIPT").ToListAsync();

如果您正在使用EF Core 2.1

如果您正在使用2018年5月7日发布的EF Core 2.1候选版本1，您可以利用提议的新功能，即查询类型:

除了实体类型，EF Core模型还可以包含查询类型， 哪些可以用于对数据进行数据库查询 没有映射到实体类型。

什么时候使用查询类型?

作为临时FromSql()查询的返回类型。 映射到数据库视图。 映射到没有定义主键的表。 映射到模型中定义的查询。

所以你不再需要做所有的黑客或变通方法来回答你的问题。只需遵循以下步骤:

首先，您定义了一个DbQuery<T>类型的新属性，其中T是将携带SQL查询列值的类的类型。在你的DbContext中，你会有这个:

public DbQuery<SomeModel> SomeModels { get; set; }

其次，使用FromSql方法，就像使用DbSet<T>一样:

var result = context.SomeModels.FromSql("SQL_SCRIPT").ToList();
var result = await context.SomeModels.FromSql("SQL_SCRIPT").ToListAsync();

还要注意dbcontext是部分类，所以你可以创建一个或多个单独的文件来组织最适合你的“原始SQL DbQuery”定义。