C# Expressions.MethodCallExpression类代码示例

        public Expression Translate(MethodCallExpression methodCallExpression, N1QlExpressionTreeVisitor expressionTreeVisitor)
        {
            if (methodCallExpression == null)
            {
                throw new ArgumentNullException("methodCallExpression");
            }

            var expression = expressionTreeVisitor.Expression;

            expression.Append("SUBSTR(");
            expressionTreeVisitor.VisitExpression(methodCallExpression.Object);
            expression.Append(", ");
            expressionTreeVisitor.VisitExpression(methodCallExpression.Arguments[0]);

            if (methodCallExpression.Arguments.Count > 1)
            {
                expression.Append(", ");
                expressionTreeVisitor.VisitExpression(methodCallExpression.Arguments[1]);
            }
            else if (methodCallExpression.Method.Name == "get_Chars")
            {
                // Called str[i], so return a single character at i
                expression.Append(", 1");
            }

            expression.Append(")");

            return methodCallExpression;
        }

        // Copied this method from Microsoft.Web.Mvc.dll (MVC Futures)...
        // Microsoft.Web.Mvc.Internal.ExpresisonHelper.AddParameterValuesFromExpressionToDictionary().
        // The only change I made is saving the parameter values to TempData instead
        // of a RouteValueDictionary.
        private IDictionary<string, object> AddParameterValuesFromExpressionToTempData(TempDataDictionary tempData,
                                                                                       MethodCallExpression call)
        {
            ParameterInfo[] parameters = call.Method.GetParameters();
            var parsedParameters = new Dictionary<string, object>();

            if(parameters.Length > 0)
            {
                for(int i = 0; i < parameters.Length; i++)
                {
                    Expression expression = call.Arguments[i];
                    object obj2 = null;
                    ConstantExpression expression2 = expression as ConstantExpression;
                    if(expression2 != null)
                    {
                        obj2 = expression2.Value;
                    }
                    else
                    {
                        Expression<Func<object>> expression3 =
                            Expression.Lambda<Func<object>>(Expression.Convert(expression, typeof(object)),
                                                            new ParameterExpression[0]);
                        obj2 = expression3.Compile()();
                    }

                    tempData[RedirectParameterPrefix + parameters[i].Name] = obj2;
                    parsedParameters.Add(parameters[i].Name, obj2);
                }
            }

            return parsedParameters;
        }

        private static bool ArrayAgg(MethodCallExpression methodCall, StringBuilder queryBuilder, Action<Expression> visitExpression)
        {
            var typeName = GetTypeName(methodCall.Type);
            if (typeName == null)
                return false;
            var sqe = methodCall.Arguments[0] as SubQueryExpression;
            if (sqe != null)
            {
                var me = sqe.QueryModel.SelectClause.Selector as MemberExpression;
                queryBuilder.Append("(SELECT cast(collect(");
                if (me != null)
                    queryBuilder.Append('"').Append(me.Member.Name).Append('"');
                else //TODO detect supported selectors - only identity
                    visitExpression(sqe.QueryModel.SelectClause.Selector);
                queryBuilder.Append(')');
            }
            else queryBuilder.Append("SELECT cast(collect($sq) ");
            queryBuilder.Append(" AS ").Append(typeName).Append(") FROM ");
            if (methodCall.Arguments[0] is MemberExpression)
                queryBuilder.Append("TABLE(");
            else queryBuilder.Append('(');
            visitExpression(methodCall.Arguments[0]);
            queryBuilder.Append(") $sq)");

            return true;
        }

        protected override Expression VisitMethodCall(MethodCallExpression methodCallExpression)
        {
            Check.NotNull(methodCallExpression, nameof(methodCallExpression));

            if (methodCallExpression.Method.IsGenericMethod)
            {
                var methodInfo = methodCallExpression.Method.GetGenericMethodDefinition();

                if (ReferenceEquals(methodInfo, EntityQueryModelVisitor.PropertyMethodInfo))
                {
                    var newArg0 = Visit(methodCallExpression.Arguments[0]);

                    if (newArg0 != methodCallExpression.Arguments[0])
                    {
                        return Expression.Call(
                            methodCallExpression.Method,
                            newArg0,
                            methodCallExpression.Arguments[1]);
                    }

                    return methodCallExpression;
                }
            }

            return base.VisitMethodCall(methodCallExpression);
        }

        /// <summary>
        ///     Replaces calls to DbContext.Set() with an expression for the equivalent <see cref="ObjectQuery" />.
        /// </summary>
        /// <param name="node"> The node to replace. </param>
        /// <returns> A new node, which may have had the replacement made. </returns>
        protected override Expression VisitMethodCall(MethodCallExpression node)
        {
            Check.NotNull(node, "node");

            // We are looking for either the generic or non-generic Set method on DbContext.
            // However, we don't constrain to this so if you write your own parameterless method on
            // a derived DbContext, then we will work with this as well.
            if (typeof(DbContext).IsAssignableFrom(node.Method.DeclaringType))
            {
                var memberExpression = node.Object as MemberExpression;
                if (memberExpression != null)
                {
                    // Only try to invoke the method if it is on the context, is not parameterless, and is not attributed
                    // as a function.
                    var context = GetContextFromConstantExpression(memberExpression.Expression, memberExpression.Member);
                    if (context != null
                        &&
                        !node.Method.GetCustomAttributes(typeof(DbFunctionAttribute), false).Any()
                        &&
                        node.Method.GetParameters().Length == 0)
                    {
                        var expression =
                            CreateObjectQueryConstant(
                                node.Method.Invoke(context, SetAccessBindingFlags, null, null, null));
                        if (expression != null)
                        {
                            return expression;
                        }
                    }
                }
            }

            return base.VisitMethodCall(node);
        }

        public Expression Translate(MethodCallExpression methodCallExpression, N1QlExpressionTreeVisitor expressionTreeVisitor)
        {
            if (methodCallExpression == null)
            {
                throw new ArgumentNullException("methodCallExpression");
            }

            var expression = expressionTreeVisitor.Expression;

            expression.Append("(");
            expressionTreeVisitor.VisitExpression(methodCallExpression.Object);
            expression.Append(" LIKE '%");

            var indexInsertStarted = expression.Length;

            expressionTreeVisitor.VisitExpression(methodCallExpression.Arguments[0]);

            var indexInsertEnded = expression.Length;

            expression.Append("%')");

            //Remove extra quote marks which have been added due to the string in the clause, these aren't needed as they have been added already in this case.
            expression.Remove(indexInsertStarted, 1);
            expression.Remove(indexInsertEnded - 2, 1);

            return methodCallExpression;
        }

        public Expression Translate(MethodCallExpression methodCallExpression, N1QlExpressionTreeVisitor expressionTreeVisitor)
        {
            if (methodCallExpression == null)
            {
                throw new ArgumentNullException("methodCallExpression");
            }

            var argument = methodCallExpression.Arguments[0];
            var methodCallArgument = argument as MethodCallExpression;

            if ((methodCallArgument != null) && SupportMethods.Contains(methodCallArgument.Method))
            {
                // Two method calls are reversing each other, so just skip them both

                return expressionTreeVisitor.VisitExpression(methodCallArgument.Arguments[0]);
            }

            var expression = expressionTreeVisitor.Expression;

            if (methodCallExpression.Method.Name == "FromDateTime")
            {
                expression.Append("STR_TO_MILLIS(");
            }
            else
            {
                expression.Append("MILLIS_TO_STR(");
            }

            expressionTreeVisitor.VisitExpression(argument);

            expression.Append(')');

            return methodCallExpression;
        }

        protected override QueryNode VisitMethodCall(MethodCallExpression methodCall)
        {
            MethodInfo method = methodCall.Method;
            if (method.DeclaringType == typeof (Queryable) || method.DeclaringType == typeof (QueryableExtensions))
                return base.VisitMethodCall(methodCall);

            // PATCH: this fixes querying on interfaces using indexers
            if (method.DeclaringType == ItemType || (method.DeclaringType != null && method.DeclaringType.IsAssignableFrom(ItemType)))
                return VisitItemMethod(methodCall);
            // END PATCH

            if (method.DeclaringType == typeof (string) || method.DeclaringType == typeof (MethodExtensions))
                return base.VisitMethodCall(methodCall);

            // PATCH: this fixes querying using ICollections on interfaces
            if (method.DeclaringType != null && method.DeclaringType.GetInterfaces().Any(x => x.IsGenericType && x.GetGenericTypeDefinition() == typeof(ICollection<>)))
            {
                return VisitICollectionMethod(methodCall);
            }
            // END PATCH

            if (method.DeclaringType == typeof(Enumerable) && methodCall.Arguments.Count > 0 && methodCall.Arguments.First() is MemberExpression)
            {
                Type declaringType = ((MemberExpression)methodCall.Arguments.First()).Member.DeclaringType;

                // PATCH: fixes querying on interfaces using LINQ Enumerable extension methods
                if (declaringType == ItemType || (declaringType != null && declaringType.IsAssignableFrom(ItemType)))
                    return VisitLinqEnumerableExtensionMethod(methodCall);
            }

            return EvaluateMethodCall(methodCall);
        }

 /// <summary>
 /// 访问指定的方法
 /// </summary>
 /// <param name="theEntityType">实体的类型</param>
 /// <param name="m">访问方法调用相关的表达式</param>
 /// <param name="tableAlias">表的别名</param>
 /// <param name="colConditionParts">存储条件节点的栈</param>
 /// <param name="colParameterNames">存储参数名称的列表</param>
 /// <param name="colDbTypes">存储数据库字段类型的列表</param>
 /// <param name="colArguments">存储条件值的列表</param>
 public static void Visit(Type theEntityType, MethodCallExpression m, string tableAlias, Stack<string> colConditionParts, List<string> colParameterNames, List<DbType> colDbTypes, List<object> colArguments)
 {
     if (m.Object is MemberExpression)
     {
         //类似n.Name.StartsWith("吴")这样的调用
         if (m.Object.Type == typeof(string))
         {
             StringMethodCallVisitor.Visit(theEntityType, m, tableAlias, colConditionParts, colParameterNames, colDbTypes, colArguments);
         }
         else
         {
             throw new Exception("暂不支持{" + m.ToString() + "}的调用!");
         }
     }
     else if (m.Object is ConstantExpression)
     {
         //类似"ABCD".Contains(n.Name)这样的调用
         var cons = m.Object as ConstantExpression;
         if (cons.Type == typeof(string))
         {
             StringMethodCallVisitor.Visit(theEntityType, m, tableAlias, colConditionParts, colParameterNames, colDbTypes, colArguments);
         }
         else
         {
             throw new Exception("暂不支持{" + m.ToString() + "}的调用!");
         }
     }
     else
     {
        throw new Exception("暂不支持{" + m.ToString() + "}的调用!");
     }
 }

        protected override Expression VisitMethodCall(MethodCallExpression node)
        {
            Expression retExpr = null;

            if (node.Method.Name == _functionName)
            {
                var str = node.ToString();
                MethodCall call;
                if (_methodCalls.TryGetValue(str, out call))
                {
                    ++call.CallCount;
                }
                else
                {
                    call = new MethodCall(node, Expression.Parameter(node.Type, "param" + (_methodCalls.Count)));
                    _methodCalls.Add(str, call);
                }

                retExpr = call.Parameter;
            }
            else
                retExpr = base.VisitMethodCall(node);

            return retExpr;
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="ObjectDeserialiserQuerySink"/> class.
        /// </summary>
        /// <param name="originalType">the original type that the query was made against.</param>
        /// <param name="instanceType">the type of the object that must be returned.</param>
        /// <param name="instanceName">Name of the instance (i.e the alias used in both the LINQ and SPARQL queries).</param>
        /// <param name="distinct">if set to <c>true</c> discard duplicate answers.</param>
        /// <param name="selectExpression">The select expression (derived from the the LINQ query). Used to help in deserialisation.</param>
        /// <param name="context">The data context that will monitor the objects created (not yet used).</param>
        public ObjectDeserialiserQuerySink(
            Type originalType,
            Type instanceType,
            string instanceName,
            bool distinct,
            MethodCallExpression selectExpression,
            RdfDataContext context)
        {
            #region Tracing

#line hidden
            if (Logger.IsDebugEnabled)
            {
                Logger.Debug("Deserialising {0}.", instanceType.Name);
            }
#line default

            #endregion

            SelectExpression = selectExpression;
            this.originalType = originalType;
            this.instanceType = instanceType;
            InstanceName = instanceName;
            Distinct = distinct;
            DataContext = context;
            IncomingResults = new ArrayList();
        }

        protected override Expression VisitMethodCall(MethodCallExpression methodCallExpression)
        {
            var newMethodCallExpression = (MethodCallExpression)base.VisitMethodCall(methodCallExpression);

            if (EntityQueryModelVisitor.IsPropertyMethod(methodCallExpression.Method))
            {
                var subQueryExpression = newMethodCallExpression.Arguments[0] as SubQueryExpression;
                var subSelector = subQueryExpression?.QueryModel.SelectClause.Selector as QuerySourceReferenceExpression;

                if (subSelector != null)
                {
                    var subQueryModel = subQueryExpression.QueryModel;

                    subQueryModel.SelectClause.Selector
                        = methodCallExpression
                            .Update(
                                null,
                                new[]
                                {
                                    subSelector,
                                    methodCallExpression.Arguments[1]
                                });

                    subQueryModel.ResultTypeOverride = subQueryModel.SelectClause.Selector.Type;

                    return new SubQueryExpression(subQueryModel);
                }
            }

            return newMethodCallExpression;
        }

        internal override Expression VisitMethodCall(MethodCallExpression m)
        {
            Expression obj = this.Visit(m.Object);
            ReadOnlyCollection<Expression> args = this.VisitExpressionList(m.Arguments);

            // check for args changed
            if (obj != m.Object || args != m.Arguments)
            {
                MethodInfo mInfo = m.Method;
                Type[] typeArgs = (mInfo.IsGenericMethod) ? mInfo.GetGenericArguments() : null;

                if ((mInfo.IsStatic || mInfo.DeclaringType.IsAssignableFrom(obj.Type))
                    && ArgsMatch(mInfo, args, typeArgs))
                {
                    // current method is still valid
                    return Expression.Call(obj, mInfo, args);
                }
                else if (mInfo.DeclaringType == typeof(Queryable))
                {
                    // convert Queryable method to Enumerable method
                    MethodInfo seqMethod = FindEnumerableMethod(mInfo.Name, args, typeArgs);
                    args = this.FixupQuotedArgs(seqMethod, args);
                    return Expression.Call(obj, seqMethod, args);
                }
                else
                {
                    // rebind to new method
                    MethodInfo method = FindMethod(mInfo.DeclaringType, mInfo.Name, args, typeArgs);
                    args = this.FixupQuotedArgs(method, args);
                    return Expression.Call(obj, method, args);
                }
            }
            return m;
        }

		protected override Expression VisitMethodCallExpression(MethodCallExpression expression)
		{
			var method = expression.Method.IsGenericMethod
							 ? expression.Method.GetGenericMethodDefinition()
							 : expression.Method;

			if (_pagingMethods.Contains(method) && !_sessionFactory.Dialect.SupportsVariableLimit)
			{
				//TODO: find a way to make this code cleaner
				var query = VisitExpression(expression.Arguments[0]);
				var arg = expression.Arguments[1];

				if (query == expression.Arguments[0])
					return expression;

				return Expression.Call(null, expression.Method, query, arg);
			}

			if (VisitorUtil.IsDynamicComponentDictionaryGetter(expression, _sessionFactory))
			{
				return expression;
			}

			return base.VisitMethodCallExpression(expression);
		}

		public override bool CanHandle(MethodCallExpression expression)
		{
			//////Contract.Assert(expression.Method != null);

			return expression.Method.DeclaringType == typeof(Math)
				   && expression.Method.Name == "Floor";
		}