Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web/UI/WebControls/QueryableHelpers.cs

@@ -0,0 +1,38 @@
+using System.Linq;
+using System.Web.Util;
+
+namespace System.Web.UI.WebControls {
+
+    internal static class QueryableHelpers {
+
+        //Methods in this class are found using GetMethod - so avoid defining overloads of the methods. 
+
+        //This method is a helper to be able to use reflection on only this method instead of each SortyBy, Skip and Take methods.
+        public static IQueryable<T> SortandPageHelper<T>(IQueryable<T> queryable, int? startRowIndex, int? maxRowIndex, string sortExpression) where T : class {
+            if (queryable == null)
+                throw new ArgumentNullException("queryable");
+
+            if (!String.IsNullOrEmpty(sortExpression)) {
+                queryable = queryable.SortBy<T>(sortExpression);
+            }
+
+            if (startRowIndex != null && maxRowIndex != null) {
+                queryable = queryable.Skip<T>((int)startRowIndex).Take<T>((int)maxRowIndex);
+            }
+
+            return queryable;
+        }
+
+        //This method is a helper to be able to use GetMethod to get this one method and execute instead of finding the Count method on Queryable class.
+        public static int CountHelper<T>(IQueryable<T> queryable) where T : class {
+            if (queryable == null)
+                throw new ArgumentNullException("queryable");
+
+            return queryable.Count<T>();
+        }
+
+        public static bool IsOrderingMethodFound<T>(IQueryable<T> queryable) where T : class {
+            return OrderingMethodFinder.OrderMethodExists(queryable.Expression);
+        }
+    }
+}