added alter queryable service.

Demo/DynamicQueries/ContactQueryableProvider.cs

@@ -6,6 +6,15 @@ using System.Threading.Tasks;
 
 namespace Demo.DynamicQueries
 {
+    public class SearchContactParamsService : IAlterQueryableService<Contact, Contact, SearchContactParams>
+    {
+        public Task<IQueryable<Contact>> AlterQueryableAsync(IQueryable<Contact> query, IDynamicQueryParams<SearchContactParams> dynamicQuery, CancellationToken cancellationToken = default)
+        {
+            var safe = dynamicQuery.GetParams()?.SearchDisplayName;
+            return Task.FromResult(query.Where(t => t.DisplayName.Contains(safe)));
+        }
+    }
+
     public class ContactQueryableProvider : IQueryableProvider<Contact>
     {
         public Task<IQueryable<Contact>> GetQueryableAsync(object query, CancellationToken cancelllationToken = default)

Demo/Startup.cs

@@ -63,7 +63,8 @@ namespace Demo
         {
             services.AddTransient<IQueryableProvider<Contact>, ContactQueryableProvider>();
             services.AddDynamicQuery<Contact>();
-            services.AddDynamicQueryWithParams<Contact, SearchContactParams>(name: "SearchContacts");
+            services.AddDynamicQueryWithParams<Contact, SearchContactParams>(name: "SearchContacts")
+                .AddAlterQueryableWithParams<Contact, SearchContactParams, SearchContactParamsService>();
         }
 
         private void AddCommands(IServiceCollection services)

PoweredSoft.CQRS.DynamicQuery.Abstractions/IAlterQueryableService.cs

@@ -2,17 +2,18 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace PoweredSoft.CQRS.DynamicQuery.Abstractions
 {
     public interface IAlterQueryableService<TSource, TDestination>
     {
-        Task<IQueryable<TSource>> AlterQueryableAsync(IQueryable<TSource> query, IDynamicQuery dynamicQuery);
+        Task<IQueryable<TSource>> AlterQueryableAsync(IQueryable<TSource> query, IDynamicQuery dynamicQuery, CancellationToken cancellationToken = default);
     }
     public interface IAlterQueryableService<TSource, TDestination, TParams>
         where TParams : class
     {
-        Task<IQueryable<TSource>> AlterQueryableAsync(IQueryable<TSource> query, IDynamicQueryParams<TParams> dynamicQuery);
+        Task<IQueryable<TSource>> AlterQueryableAsync(IQueryable<TSource> query, IDynamicQueryParams<TParams> dynamicQuery, CancellationToken cancellationToken = default);
     }
 }

PoweredSoft.CQRS.DynamicQuery/DynamicQueryHandler.cs

@@ -1,6 +1,7 @@
 using PoweredSoft.CQRS.DynamicQuery.Abstractions;
 using PoweredSoft.DynamicQuery.Core;
 using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -12,7 +13,9 @@ namespace PoweredSoft.CQRS.DynamicQuery
         where TSource : class
         where TDestination : class
     {
-        public DynamicQueryHandler(IQueryHandlerAsync queryHandlerAsync, IEnumerable<IQueryableProvider<TSource>> queryableProviders) : base(queryHandlerAsync, queryableProviders)
+        public DynamicQueryHandler(IQueryHandlerAsync queryHandlerAsync, 
+            IEnumerable<IQueryableProvider<TSource>> queryableProviders,
+            IEnumerable<IAlterQueryableService<TSource, TDestination>> alterQueryableServices) : base(queryHandlerAsync, queryableProviders, alterQueryableServices)
         {
         }
 
@@ -29,8 +32,27 @@ namespace PoweredSoft.CQRS.DynamicQuery
         where TDestination : class
         where TParams : class
     {
-        public DynamicQueryHandler(IQueryHandlerAsync queryHandlerAsync, IEnumerable<IQueryableProvider<TSource>> queryableProviders) : base(queryHandlerAsync, queryableProviders)
+        private readonly IEnumerable<IAlterQueryableService<TSource, TDestination, TParams>> alterQueryableServicesWithParams;
+
+        public DynamicQueryHandler(IQueryHandlerAsync queryHandlerAsync, 
+            IEnumerable<IQueryableProvider<TSource>> queryableProviders,
+            IEnumerable<IAlterQueryableService<TSource, TDestination>> alterQueryableServices,
+            IEnumerable<IAlterQueryableService<TSource, TDestination, TParams>> alterQueryableServicesWithParams) : base(queryHandlerAsync, queryableProviders, alterQueryableServices)
         {
+            this.alterQueryableServicesWithParams = alterQueryableServicesWithParams;
+        }
+
+        protected override async Task<IQueryable<TSource>> AlterSourceAsync(IQueryable<TSource> source, IDynamicQuery query, CancellationToken cancellationToken)
+        {
+            source =  await base.AlterSourceAsync(source, query, cancellationToken);
+
+            if (query is IDynamicQueryParams<TParams> withParams)
+            {
+                foreach (var it in alterQueryableServicesWithParams)
+                    source = await it.AlterQueryableAsync(source, withParams, cancellationToken);
+            }
+
+            return source;
         }
 
         public Task<IQueryExecutionResult<TDestination>> HandleAsync(IDynamicQuery<TSource, TDestination, TParams> query, CancellationToken cancellationToken = default)

PoweredSoft.CQRS.DynamicQuery/DynamicQueryHandlerBase.cs

@@ -15,12 +15,15 @@ namespace PoweredSoft.CQRS.DynamicQuery
     {
         private readonly IQueryHandlerAsync queryHandlerAsync;
         private readonly IEnumerable<IQueryableProvider<TSource>> queryableProviders;
+        private readonly IEnumerable<IAlterQueryableService<TSource, TDestination>> alterQueryableServices;
 
         public DynamicQueryHandlerBase(IQueryHandlerAsync queryHandlerAsync, 
-            IEnumerable<IQueryableProvider<TSource>> queryableProviders)
+            IEnumerable<IQueryableProvider<TSource>> queryableProviders,
+            IEnumerable<IAlterQueryableService<TSource, TDestination>> alterQueryableServices)
         {
             this.queryHandlerAsync = queryHandlerAsync;
             this.queryableProviders = queryableProviders;
+            this.alterQueryableServices = alterQueryableServices;
         }
 
         protected virtual Task<IQueryable<TSource>> GetQueryableAsync(IDynamicQuery query, CancellationToken cancellationToken = default)
@@ -56,9 +59,12 @@ namespace PoweredSoft.CQRS.DynamicQuery
             return result;
         }
 
-        protected virtual Task<IQueryable<TSource>> AlterSourceAsync(IQueryable<TSource> source, IDynamicQuery query, CancellationToken cancellationToken)
+        protected virtual async Task<IQueryable<TSource>> AlterSourceAsync(IQueryable<TSource> source, IDynamicQuery query, CancellationToken cancellationToken)
         {
-            return Task.FromResult(source);
+            foreach (var t in alterQueryableServices)
+                source = await t.AlterQueryableAsync(source, query, cancellationToken);
+
+            return source;
         }
 
         protected virtual IQueryCriteria CreateCriteriaFromQuery(IDynamicQuery query)