From a7937cd500f684d51e10c160a0c796313a807cd0 Mon Sep 17 00:00:00 2001
From: David Lebee <david@poweredsoft.com>
Date: Fri, 26 Oct 2018 16:13:42 -0500
Subject: [PATCH] flattening support on wrap select.

---
 PoweredSoft.DynamicLinq.Test/GroupingTests.cs        |  5 +++--
 PoweredSoft.DynamicLinq/Helpers/QueryableHelpers.cs  | 10 ++++++++--
 .../Helpers/QueryablePathHelpers.cs                  | 12 ------------
 3 files changed, 11 insertions(+), 16 deletions(-)
 delete mode 100644 PoweredSoft.DynamicLinq/Helpers/QueryablePathHelpers.cs

diff --git a/PoweredSoft.DynamicLinq.Test/GroupingTests.cs b/PoweredSoft.DynamicLinq.Test/GroupingTests.cs
index 7ea08ea..5749bd8 100644
--- a/PoweredSoft.DynamicLinq.Test/GroupingTests.cs
+++ b/PoweredSoft.DynamicLinq.Test/GroupingTests.cs
@@ -9,6 +9,7 @@ using PoweredSoft.DynamicLinq.Dal;
 using System.Diagnostics;
 using PoweredSoft.DynamicLinq.Test.Helpers;
 using System.Collections;
+using PoweredSoft.DynamicLinq.Dal.Pocos;
 
 namespace PoweredSoft.DynamicLinq.Test
 {
@@ -289,7 +290,7 @@ namespace PoweredSoft.DynamicLinq.Test
         }
 
         [TestMethod]
-        public void GroupByToListWithPathWithNullChecking()
+        public void GroupByToListWithPathWithNullCheckingWithFlattening()
         {
             var limitResult = TestData.Authors;
 
@@ -300,7 +301,7 @@ namespace PoweredSoft.DynamicLinq.Test
             .Select(t => new
             {
                 Key = t.Key.AuthorFirstName,
-                Contents = t.SelectMany(t2 => t2.Posts.Select(t3 => t3.Content)).ToList()
+                Contents = t.SelectMany(t2 => t2.Posts == null ? new List<string>() : t2.Posts.Select(t3 => t3.Content)).ToList()
             })
             .ToList();
 
diff --git a/PoweredSoft.DynamicLinq/Helpers/QueryableHelpers.cs b/PoweredSoft.DynamicLinq/Helpers/QueryableHelpers.cs
index d16cef1..d9985a6 100644
--- a/PoweredSoft.DynamicLinq/Helpers/QueryableHelpers.cs
+++ b/PoweredSoft.DynamicLinq/Helpers/QueryableHelpers.cs
@@ -220,10 +220,16 @@ namespace PoweredSoft.DynamicLinq.Helpers
         {
             var selectType = parameter.Type.GenericTypeArguments.Skip(1).First();
             var innerSelectType = ((LambdaExpression)innerLambdaExpression).ReturnType;
-            var selectExpression = Expression.Call(typeof(Enumerable), "Select", new Type[] { selectType, innerSelectType }, parameter, innerLambdaExpression);
+
+            Expression selectExpression;
+            if (QueryableHelpers.IsGenericEnumerable(innerSelectType) && selectCollectionHandling == SelectCollectionHandling.Flatten)
+                selectExpression = Expression.Call(typeof(Enumerable), "SelectMany", new Type[] { selectType, innerSelectType.GenericTypeArguments.First() }, parameter, innerLambdaExpression);
+            else
+                selectExpression = Expression.Call(typeof(Enumerable), "Select", new Type[] { selectType, innerSelectType }, parameter, innerLambdaExpression);
+
             return selectExpression;
         }
-
+    
         private static Expression CreateSelectExpression(IQueryable query, ParameterExpression parameter, SelectTypes selectType, string path, SelectCollectionHandling selectCollectionHandling, bool nullChecking)
         {
             if (!IsGrouping(query))
diff --git a/PoweredSoft.DynamicLinq/Helpers/QueryablePathHelpers.cs b/PoweredSoft.DynamicLinq/Helpers/QueryablePathHelpers.cs
deleted file mode 100644
index d5b6a9a..0000000
--- a/PoweredSoft.DynamicLinq/Helpers/QueryablePathHelpers.cs
+++ /dev/null
@@ -1,12 +0,0 @@
-using System.Collections.Generic;
-using System.Linq.Expressions;
-using System.Text;
-
-namespace PoweredSoft.DynamicLinq.Helpers
-{
-
-    public static class QueryablePathHelpers
-    {
-        
-    }
-}