mcs/class/referencesource/System.Web/Util/QueryableUtility.cs

   1 using System.Linq;
   2 using System.Linq.Expressions;
   3 using System.Reflection;
   4
   5 namespace System.Web.Util {
   6     internal static class QueryableUtility {
   7         private static readonly string[] _orderMethods = new[] { "OrderBy", "ThenBy", "OrderByDescending", "ThenByDescending" };
   8         private static readonly MethodInfo[] _methods = typeof(Queryable).GetMethods(BindingFlags.Public | BindingFlags.Static);
   9
  10         private static MethodInfo GetQueryableMethod(Expression expression) {
  11             if (expression.NodeType == ExpressionType.Call) {
  12                 var call = (MethodCallExpression)expression;
  13                 if (call.Method.IsStatic && call.Method.DeclaringType == typeof(Queryable)) {
  14                     return call.Method.GetGenericMethodDefinition();
  15                 }
  16             }
  17             return null;
  18         }
  19
  20         public static bool IsQueryableMethod(Expression expression, string method) {
  21             return _methods.Where(m => m.Name == method).Contains(GetQueryableMethod(expression));
  22         }
  23
  24         public static bool IsOrderingMethod(Expression expression) {
  25             return _orderMethods.Any(method => IsQueryableMethod(expression, method));
  26         }
  27
  28     }
  29 }