Use WellKnown.KeyFieldName instead of literal

Author: alex-kulakov

Orm/Xtensive.Orm/Orm/Linq/Rewriters/AggregateOptimizer.cs

@@ -224,7 +224,7 @@ private static void AddGroupByItemWrapper(GroupByQuery groupBy, List<LambdaExpre
       var keyType = keySelector.Body.Type;
       var elementType = elementSelector.Body.Type;
       var wrapperType = typeof (GroupByItemWrapper<,>).MakeGenericType(keyType, elementType);
-      var wrapperKeyProperty = wrapperType.GetProperty("Key");
+      var wrapperKeyProperty = wrapperType.GetProperty(WellKnown.KeyFieldName);
       var wrapperElementProperty = wrapperType.GetProperty("Element");
 
       var projectionParameter = keySelector.Parameters[0];

Orm/Xtensive.Orm/Orm/Linq/Translator.Expressions.cs

@@ -391,7 +391,7 @@ protected override Expression VisitMemberAccess(MemberExpression ma)
             return VisitSequence(rootPoint.Expression);
         }
       }
-      else if (sourceExpression.GetMemberType() == MemberType.Entity && memberInfo.Name != "Key") {
+      else if (sourceExpression.GetMemberType() == MemberType.Entity && memberInfo.Name != WellKnown.KeyFieldName) {
         var type = sourceExpression.Type;
         if (sourceExpression is ParameterExpression parameter) {
           var projection = context.Bindings[parameter];
@@ -1420,7 +1420,7 @@ bool propertyFilter(PersistentFieldExpression f)
           }
           break;
         case ExtendedExpressionType.Grouping:
-          if (member.Name == "Key") {
+          if (member.Name == WellKnown.KeyFieldName) {
             return ((GroupingExpression) expression).KeyExpression;
           }
           break;

Orm/Xtensive.Orm/Orm/Linq/Translator.Queryable.cs

@@ -1225,7 +1225,7 @@ private Expression VisitGroupJoin(Expression outerSource, Expression innerSource
           innerGrouping.ResultAccessMethod);
       }
 
-      var groupingKeyPropertyInfo = groupingType.GetProperty("Key");
+      var groupingKeyPropertyInfo = groupingType.GetProperty(WellKnown.KeyFieldName);
       var groupingJoinParameter = Expression.Parameter(enumerableType, "groupingJoinParameter");
       var groupingKeyExpression = Expression.MakeMemberAccess(
         Expression.Convert(groupingJoinParameter, groupingType),

Orm/Xtensive.Orm/Orm/Operations/KeyOperation.cs

@@ -73,7 +73,7 @@ protected virtual void GetObjectData(SerializationInfo info, StreamingContext co
     /// <inheritdoc/>
     protected KeyOperation(SerializationInfo info, StreamingContext context)
     {
-      Key = Key.Parse(Domain.Demand(), info.GetString("Key"));
+      Key = Key.Parse(Domain.Demand(), info.GetString(WellKnown.KeyFieldName));
 //      Key.TypeReference = new TypeReference(Key.TypeReference.Type, TypeReferenceAccuracy.ExactType);
     }
   }