- 优化 实体基类的属性位置，优先排在最前面； #164

- 整理 实体类 Ctor 有构造函数的映射处理；#164 [wiki](https://github.com/2881099/FreeSql/wiki/%e8%bf%94%e5%9b%9e%e6%95%b0%e6%8d%ae#dto-%E6%98%A0%E5%B0%84%E6%9F%A5%E8%AF%A2)
- 优化 实体属性，支持 protected set 属性；#164

FreeSql.DbContext/Extensions/DependencyInjection.cs

@@ -15,7 +15,7 @@ static IServiceCollection AddFreeDbContext(this IServiceCollection services, Typ
                 DbContext ctx = null;
                 try
                 {
-                    var ctor = dbContextType.GetConstructors().FirstOrDefault();
+                    var ctor = dbContextType. GetConstructors().FirstOrDefault();
                     var ctorParams = ctor.GetParameters().Select(a => sp.GetService(a.ParameterType)).ToArray();
                     ctx = Activator.CreateInstance(dbContextType, ctorParams) as DbContext;
                 }

FreeSql.Tests/FreeSql.Tests/MySql/Curd/MySqlSelectTest.cs

@@ -1056,6 +1056,23 @@ public void AsTable()
                     a.Id,
                     a.Clicks
                 });
+
+            Assert.Equal(@"SELECT a.`Id` as1, a.`Clicks` as2 
+FROM (SELECT  * from (SELECT a.`Id` Id, a.`Clicks` Clicks 
+FROM `tb_topic_1` a) ftb 
+
+UNION ALL
+
+SELECT  * from (SELECT a.`Id` Id, a.`Clicks` Clicks 
+FROM `tb_topic_2` a) ftb) a 
+limit 0,20", select
+                .AsTable((type, old) => type == typeof(Topic) ? $"({sqlsss})" : null)
+                .Page(1, 20)
+                .ToSql(a => new
+                {
+                    a.Id,
+                    a.Clicks
+                }));
         }
 
         public class TestInclude_OneToManyModel1

FreeSql.Tests/FreeSql.Tests/MySql/MySqlCodeFirstTest.cs

@@ -17,11 +17,7 @@ public class MySqlCodeFirstTest
             var sql = g.mysql.CodeFirst.GetComparisonDDLStatements<测试中文表2>();
             g.mysql.CodeFirst.SyncStructure<测试中文表2>();
 
-            var item = new 测试中文表2
-            {
-                标题 = "测试标题",
-                创建时间 = DateTime.Now
-            };
+            var item = 测试中文表2.Create("测试标题", DateTime.Now);
             Assert.Equal(1, g.mysql.Insert<测试中文表2>().AppendData(item).ExecuteAffrows());
             Assert.NotEqual(Guid.Empty, item.编号);
             var item2 = g.mysql.Select<测试中文表2>().Where(a => a.编号 == item.编号).First();
@@ -32,12 +28,17 @@ public class MySqlCodeFirstTest
         class 测试中文表2
         {
             [Column(IsPrimary = true)]
-            public Guid 编号 { get; set; }
+            public Guid 编号 { get; protected set; }
 
-            public string 标题 { get; set; }
+            public string 标题 { get; protected set; }
 
             [Column(ServerTime = DateTimeKind.Local)]
-            public DateTime 创建时间 { get; set; }
+            public DateTime 创建时间 { get; protected set; }
+
+            public static 测试中文表2 Create(string title, DateTime ctm)
+            {
+                return new 测试中文表2 { 标题 = title, 创建时间 = ctm };
+            }
         }
 
         [Fact]

FreeSql/Extensions/FreeSqlGlobalExtensions.cs

@@ -47,21 +47,35 @@ public static partial class FreeSqlGlobalExtensions
     public static bool IsArrayOrList(this Type that) => that == null ? false : (that.IsArray || typeof(IList).IsAssignableFrom(that));
     public static Type NullableTypeOrThis(this Type that) => that?.IsNullableType() == true ? that.GetGenericArguments().First() : that;
     internal static string NotNullAndConcat(this string that, params object[] args) => string.IsNullOrEmpty(that) ? null : string.Concat(new object[] { that }.Concat(args));
-    static ConcurrentDictionary<Type, ParameterInfo[]> _dicGetDefaultValueFirstConstructorsParameters = new ConcurrentDictionary<Type, ParameterInfo[]>();
     public static object CreateInstanceGetDefaultValue(this Type that)
     {
         if (that == null) return null;
         if (that == typeof(string)) return default(string);
         if (that.IsArray) return Array.CreateInstance(that, 0);
-        var ctorParms = _dicGetDefaultValueFirstConstructorsParameters.GetOrAdd(that, tp => tp.GetConstructors().FirstOrDefault()?.GetParameters());
+        var ctorParms = that.InternalGetTypeConstructor0OrFirst(false)?.GetParameters();
         if (ctorParms == null || ctorParms.Any() == false) return Activator.CreateInstance(that, null);
         return Activator.CreateInstance(that, ctorParms.Select(a => Activator.CreateInstance(a.ParameterType, null)).ToArray());
     }
+    internal static NewExpression InternalNewExpression(this Type that)
+    {
+        var ctor = that.InternalGetTypeConstructor0OrFirst();
+        return Expression.New(ctor, ctor.GetParameters().Select(a => Expression.Constant(a.ParameterType.CreateInstanceGetDefaultValue(), a.ParameterType)));
+    }
+
+    static ConcurrentDictionary<Type, ConstructorInfo> _dicInternalGetTypeConstructor0OrFirst = new ConcurrentDictionary<Type, ConstructorInfo>();
+    internal static ConstructorInfo InternalGetTypeConstructor0OrFirst(this Type that, bool isThrow = true)
+    {
+        var ret = _dicInternalGetTypeConstructor0OrFirst.GetOrAdd(that, tp =>
+            tp.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, new Type[0], null) ??
+            tp.GetConstructors(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic).FirstOrDefault());
+        if (ret == null && isThrow) throw new ArgumentException($"{that.FullName} 类型无方法访问构造函数");
+        return ret;
+    }
 
     static ConcurrentDictionary<Type, Dictionary<string, PropertyInfo>> _dicGetPropertiesDictIgnoreCase = new ConcurrentDictionary<Type, Dictionary<string, PropertyInfo>>();
     public static Dictionary<string, PropertyInfo> GetPropertiesDictIgnoreCase(this Type that) => that == null ? null : _dicGetPropertiesDictIgnoreCase.GetOrAdd(that, tp =>
     {
-        var props = that.GetProperties();
+        var props = that.GetProperties().GroupBy(p => p.DeclaringType).Reverse().SelectMany(p => p); //将基类的属性位置放在前面 #164
         var dict = new Dictionary<string, PropertyInfo>(StringComparer.CurrentCultureIgnoreCase);
         foreach (var prop in props)
         {