C# IEdmTypeReference.AsActualTypeReference方法代码示例

        /// <summary>
        /// Returns true if the compared type reference is semantically equivalent to this type reference.
        /// Schema types (<see cref="IEdmSchemaType"/>) are compared by their object refs.
        /// </summary>
        /// <param name="thisType">Type reference being compared.</param>
        /// <param name="otherType">Type referenced being compared to.</param>
        /// <returns>Equivalence of the two type references.</returns>
        public static bool IsEquivalentTo(this IEdmTypeReference thisType, IEdmTypeReference otherType)
        {
            if (thisType == otherType)
            {
                return true;
            }
            
            if (thisType == null || otherType == null)
            {
                return false;
            }

            thisType = thisType.AsActualTypeReference();
            otherType = otherType.AsActualTypeReference();

            EdmTypeKind typeKind = thisType.TypeKind();
            if (typeKind != otherType.TypeKind())
            {
                return false;
            }

            if (typeKind == EdmTypeKind.Primitive)
            {
                return ((IEdmPrimitiveTypeReference)thisType).IsEquivalentTo((IEdmPrimitiveTypeReference)otherType);
            }
            else
            {
                return thisType.IsNullable == otherType.IsNullable &&
                       thisType.Definition.IsEquivalentTo(otherType.Definition);
            }
        }

        /// <summary>
        /// Determines if the type of an expression is compatible with the provided type
        /// </summary>
        /// <param name="expression">The expression to assert the type of.</param>
        /// <param name="type">The type to assert the expression as.</param>
        /// <param name="context">The context paths are to be evaluated in.</param>
        /// <param name="matchExactly">A value indicating whether the expression must match the asserted type exactly, or simply be compatible.</param>
        /// <param name="discoveredErrors">Errors produced if the expression does not match the specified type.</param>
        /// <returns>A value indicating whether the expression is valid for the given type or not.</returns>
        /// <remarks>If the expression has an associated type, this function will check that it matches the expected type and stop looking further. 
        /// If an expression claims a type, it must be validated that the type is valid for the expression. If the expression does not claim a type
        /// this method will attempt to check the validity of the expression itself with the asserted type.</remarks>
        public static bool TryCast(this IEdmExpression expression, IEdmTypeReference type, IEdmType context, bool matchExactly, out IEnumerable<EdmError> discoveredErrors)
        {
            EdmUtil.CheckArgumentNull(expression, "expression");
            type = type.AsActualTypeReference();

            // If we don't have a type to assert this passes vacuously.
            if (type == null || type.TypeKind() == EdmTypeKind.None)
            {
                discoveredErrors = Enumerable.Empty<EdmError>();
                return true;
            }

            switch (expression.ExpressionKind)
            {
                case EdmExpressionKind.IntegerConstant:
                case EdmExpressionKind.StringConstant:
                case EdmExpressionKind.BinaryConstant:
                case EdmExpressionKind.BooleanConstant:
                case EdmExpressionKind.DateTimeOffsetConstant:
                case EdmExpressionKind.DecimalConstant:
                case EdmExpressionKind.FloatingConstant:
                case EdmExpressionKind.GuidConstant:
                case EdmExpressionKind.DurationConstant:
                case EdmExpressionKind.DateConstant:
                case EdmExpressionKind.TimeOfDayConstant:
                    IEdmPrimitiveValue primitiveValue = (IEdmPrimitiveValue)expression;
                    if (primitiveValue.Type != null)
                    {
                        return TestTypeReferenceMatch(primitiveValue.Type, type, expression.Location(), matchExactly, out discoveredErrors);
                    }

                    return TryCastPrimitiveAsType(primitiveValue, type, out discoveredErrors);
                case EdmExpressionKind.Null:
                    return TryCastNullAsType((IEdmNullExpression)expression, type, out discoveredErrors);
                case EdmExpressionKind.Path:
                case EdmExpressionKind.PropertyPath:
                case EdmExpressionKind.NavigationPropertyPath:
                    return TryCastPathAsType((IEdmPathExpression)expression, type, context, matchExactly, out discoveredErrors);
                case EdmExpressionKind.OperationApplication:
                    IEdmApplyExpression applyExpression = (IEdmApplyExpression)expression;
                    if (applyExpression.AppliedOperation != null)
                    {
                        IEdmOperation operation = applyExpression.AppliedOperation as IEdmOperation;
                        if (operation != null)
                        {
                            return TestTypeReferenceMatch(operation.ReturnType, type, expression.Location(), matchExactly, out discoveredErrors);
                        }
                    }

                    // If we don't have the applied function we just assume that it will work.
                    discoveredErrors = Enumerable.Empty<EdmError>();
                    return true;
                case EdmExpressionKind.If:
                    return TryCastIfAsType((IEdmIfExpression)expression, type, context, matchExactly, out discoveredErrors);
                case EdmExpressionKind.IsType:
                    return TestTypeReferenceMatch(EdmCoreModel.Instance.GetBoolean(false), type, expression.Location(), matchExactly, out discoveredErrors);
                case EdmExpressionKind.Record:
                    IEdmRecordExpression recordExpression = (IEdmRecordExpression)expression;
                    if (recordExpression.DeclaredType != null)
                    {
                        return TestTypeReferenceMatch(recordExpression.DeclaredType, type, expression.Location(), matchExactly, out discoveredErrors);
                    }

                    return TryCastRecordAsType(recordExpression, type, context, matchExactly, out discoveredErrors);
                case EdmExpressionKind.Collection:
                    IEdmCollectionExpression collectionExpression = (IEdmCollectionExpression)expression;
                    if (collectionExpression.DeclaredType != null)
                    {
                        return TestTypeReferenceMatch(collectionExpression.DeclaredType, type, expression.Location(), matchExactly, out discoveredErrors);
                    }

                    return TryCastCollectionAsType(collectionExpression, type, context, matchExactly, out discoveredErrors);
                case EdmExpressionKind.Labeled:
                    return TryCast(((IEdmLabeledExpression)expression).Expression, type, context, matchExactly, out discoveredErrors);
                case EdmExpressionKind.Cast:
                    return TestTypeReferenceMatch(((IEdmCastExpression)expression).Type, type, expression.Location(), matchExactly, out discoveredErrors);
                case EdmExpressionKind.LabeledExpressionReference:
                    return TryCast(((IEdmLabeledExpressionReferenceExpression)expression).ReferencedLabeledExpression, type, out discoveredErrors);
                default:
                    discoveredErrors = new EdmError[] { new EdmError(expression.Location(), EdmErrorCode.ExpressionNotValidForTheAssertedType, Edm.Strings.EdmModel_Validator_Semantic_ExpressionNotValidForTheAssertedType) };
                    return false;
            }
        }