Empty group to create easy totals

PoweredSoft · Oct 21, 2018 · 49d9d92 · 49d9d92
1 parent 019d34b
commit 49d9d92
Showing 1 changed file with 11 additions and 0 deletions.
diff --git a/PoweredSoft.DynamicLinq/Extensions/QueryableExtensions.cs b/PoweredSoft.DynamicLinq/Extensions/QueryableExtensions.cs
@@ -157,5 +157,16 @@ public static long LongCount(this IQueryable query)
             var result = method.Invoke(null, new object[] {query});
             return (long) result;
         }
+
+        public static IQueryable EmptyGroupBy(this IQueryable queryable, Type underlyingType)
+        {
+            var parameter = Expression.Parameter(underlyingType);
+            var genericMethod = Constants.GroupByMethod.MakeGenericMethod(underlyingType, typeof(bool));
+            var trueConstant = Expression.Constant(true);
+            var lambda = Expression.Lambda(trueConstant, parameter);
+            var groupByExpression = Expression.Call(genericMethod, queryable.Expression, lambda);
+            var result = queryable.Provider.CreateQuery(groupByExpression);
+            return result;
+        }
     }
 }