[#65]

nuget-publish.bat

@@ -1,8 +1,8 @@
 :start
 ::定义版本
-set EFCORE2=2.3.1.29
-set EFCORE3=3.3.1.29
-set EFCORE5=5.3.1.29
+set EFCORE2=2.3.1.30
+set EFCORE3=3.3.1.30
+set EFCORE5=5.3.1.30
 
 ::删除所有bin与obj下的文件
 @echo off

src/ShardingCore/Extensions/StringFieldOrderExtension.cs

@@ -61,7 +61,7 @@ namespace ShardingCore.Extensions
             }
             else
             {
-                var comparer = Activator.CreateInstance(typeof(InMemoryShardingComparer<>).GetGenericType0(selectorResultType), shardingComparer);
+                var comparer = shardingComparer.CreateComparer(selectorResultType);
                 resultExp = Expression.Call(typeof(Queryable), methodName,
                     new Type[] { type, selectorResultType },
                     source.Expression, Expression.Quote(selector),Expression.Constant(comparer));

src/ShardingCore/Sharding/Abstractions/IShardingComparer.cs

@@ -13,6 +13,7 @@ namespace ShardingCore.Sharding.Abstractions
     public interface IShardingComparer
     {
         int Compare(IComparable a, IComparable b,bool asc);
+        object CreateComparer(Type comparerType);
     }
 
     public interface IShardingComparer<TShardingDbContext> : IShardingComparer where TShardingDbContext:DbContext,IShardingDbContext

src/ShardingCore/Sharding/CSharpLanguageShardingComparer.cs

@@ -1,7 +1,9 @@
 using System;
+using System.Collections.Concurrent;
 using Microsoft.EntityFrameworkCore;
 using ShardingCore.Extensions;
 using ShardingCore.Sharding.Abstractions;
+using ShardingCore.Sharding.Internals;
 
 namespace ShardingCore.Sharding
 {
@@ -13,9 +15,18 @@ namespace ShardingCore.Sharding
 */
     public class CSharpLanguageShardingComparer<TShardingDbContext>:IShardingComparer<TShardingDbContext> where TShardingDbContext:DbContext,IShardingDbContext
     {
+        private readonly ConcurrentDictionary<Type, object> _comparers = new ConcurrentDictionary<Type, object>();
         public int Compare(IComparable x, IComparable y, bool asc)
         {
             return x.SafeCompareToWith(y, asc);
         }
+
+        public object CreateComparer(Type comparerType)
+        {
+            var comparer = _comparers.GetOrAdd(comparerType,
+                key => Activator.CreateInstance(typeof(InMemoryShardingComparer<>).GetGenericType0(comparerType),
+                    this));
+            return comparer;
+        }
     }
 }