C# JsonReader.ReadAndAssert方法代码示例

        /// <summary>
        /// Reads the JSON representation of the object.
        /// </summary>
        /// <param name="reader">The <see cref="JsonReader"/> to read from.</param>
        /// <param name="objectType">Type of the object.</param>
        /// <param name="existingValue">The existing value of object being read.</param>
        /// <param name="serializer">The calling serializer.</param>
        /// <returns>The object value.</returns>
        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            if (reader.TokenType == JsonToken.Null)
            {
                return null;
            }

            // handle typed datasets
            DataSet ds = (objectType == typeof(DataSet))
                ? new DataSet()
                : (DataSet)Activator.CreateInstance(objectType);

            DataTableConverter converter = new DataTableConverter();

            reader.ReadAndAssert();

            while (reader.TokenType == JsonToken.PropertyName)
            {
                DataTable dt = ds.Tables[(string)reader.Value];
                bool exists = (dt != null);

                dt = (DataTable)converter.ReadJson(reader, typeof(DataTable), dt, serializer);

                if (!exists)
                {
                    ds.Tables.Add(dt);
                }

                reader.ReadAndAssert();
            }

            return ds;
        }

        /// <summary>
        /// Reads the JSON representation of the object.
        /// </summary>
        /// <param name="reader">The <see cref="JsonReader"/> to read from.</param>
        /// <param name="objectType">Type of the object.</param>
        /// <param name="existingValue">The existing value of object being read.</param>
        /// <param name="serializer">The calling serializer.</param>
        /// <returns>The object value.</returns>
        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            EnsureReflectionObject(objectType);

            object entityKeyMember = _reflectionObject.Creator();

            ReadAndAssertProperty(reader, KeyPropertyName);
            reader.ReadAndAssert();
            _reflectionObject.SetValue(entityKeyMember, KeyPropertyName, reader.Value.ToString());

            ReadAndAssertProperty(reader, TypePropertyName);
            reader.ReadAndAssert();
            string type = reader.Value.ToString();

            Type t = Type.GetType(type);

            ReadAndAssertProperty(reader, ValuePropertyName);
            reader.ReadAndAssert();
            _reflectionObject.SetValue(entityKeyMember, ValuePropertyName, serializer.Deserialize(reader, t));

            reader.ReadAndAssert();

            return entityKeyMember;
        }

        /// <summary>
        /// Reads the JSON representation of the object.
        /// </summary>
        /// <param name="reader">The <see cref="JsonReader"/> to read from.</param>
        /// <param name="objectType">Type of the object.</param>
        /// <param name="existingValue">The existing value of object being read.</param>
        /// <param name="serializer">The calling serializer.</param>
        /// <returns>The object value.</returns>
        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            if (reader.TokenType == JsonToken.Null)
            {
                return null;
            }

            DataTable dt = existingValue as DataTable;

            if (dt == null)
            {
                // handle typed datasets
                dt = (objectType == typeof(DataTable))
                    ? new DataTable()
                    : (DataTable)Activator.CreateInstance(objectType);
            }

            // DataTable is inside a DataSet
            // populate the name from the property name
            if (reader.TokenType == JsonToken.PropertyName)
            {
                dt.TableName = (string)reader.Value;

                reader.ReadAndAssert();

                if (reader.TokenType == JsonToken.Null)
                {
                    return dt;
                }
            }

            if (reader.TokenType != JsonToken.StartArray)
            {
                throw JsonSerializationException.Create(reader, "Unexpected JSON token when reading DataTable. Expected StartArray, got {0}.".FormatWith(CultureInfo.InvariantCulture, reader.TokenType));
            }

            reader.ReadAndAssert();

            while (reader.TokenType != JsonToken.EndArray)
            {
                CreateRow(reader, dt, serializer);

                reader.ReadAndAssert();
            }

            return dt;
        }

        private static Type GetColumnDataType(JsonReader reader)
        {
            JsonToken tokenType = reader.TokenType;

            switch (tokenType)
            {
                case JsonToken.Integer:
                case JsonToken.Boolean:
                case JsonToken.Float:
                case JsonToken.String:
                case JsonToken.Date:
                case JsonToken.Bytes:
                    return reader.ValueType;
                case JsonToken.Null:
                case JsonToken.Undefined:
                    return typeof(string);
                case JsonToken.StartArray:
                    reader.ReadAndAssert();
                    if (reader.TokenType == JsonToken.StartObject)
                    {
                        return typeof(DataTable); // nested datatable
                    }

                    Type arrayType = GetColumnDataType(reader);
                    return arrayType.MakeArrayType();
                default:
                    throw JsonSerializationException.Create(reader, "Unexpected JSON token when reading DataTable: {0}".FormatWith(CultureInfo.InvariantCulture, tokenType));
            }
        }

        private static void CreateRow(JsonReader reader, DataTable dt, JsonSerializer serializer)
        {
            DataRow dr = dt.NewRow();
            reader.ReadAndAssert();

            while (reader.TokenType == JsonToken.PropertyName)
            {
                string columnName = (string)reader.Value;

                reader.ReadAndAssert();

                DataColumn column = dt.Columns[columnName];
                if (column == null)
                {
                    Type columnType = GetColumnDataType(reader);
                    column = new DataColumn(columnName, columnType);
                    dt.Columns.Add(column);
                }

                if (column.DataType == typeof(DataTable))
                {
                    if (reader.TokenType == JsonToken.StartArray)
                    {
                        reader.ReadAndAssert();
                    }

                    DataTable nestedDt = new DataTable();

                    while (reader.TokenType != JsonToken.EndArray)
                    {
                        CreateRow(reader, nestedDt, serializer);

                        reader.ReadAndAssert();
                    }

                    dr[columnName] = nestedDt;
                }
                else if (column.DataType.IsArray && column.DataType != typeof(byte[]))
                {
                    if (reader.TokenType == JsonToken.StartArray)
                    {
                        reader.ReadAndAssert();
                    }

                    List<object> o = new List<object>();

                    while (reader.TokenType != JsonToken.EndArray)
                    {
                        o.Add(reader.Value);
                        reader.ReadAndAssert();
                    }

                    Array destinationArray = Array.CreateInstance(column.DataType.GetElementType(), o.Count);
                    Array.Copy(o.ToArray(), destinationArray, o.Count);

                    dr[columnName] = destinationArray;
                }
                else
                {
                    object columnValue = (reader.Value != null)
                        ? serializer.Deserialize(reader, column.DataType) ?? DBNull.Value
                        : DBNull.Value;

                    dr[columnName] = columnValue;
                }

                reader.ReadAndAssert();
            }

            dr.EndEdit();
            dt.Rows.Add(dr);
        }

        /// <summary>
        /// Reads the JSON representation of the object.
        /// </summary>
        /// <param name="reader">The <see cref="JsonReader"/> to read from.</param>
        /// <param name="objectType">Type of the object.</param>
        /// <param name="existingValue">The existing value of object being read.</param>
        /// <param name="serializer">The calling serializer.</param>
        /// <returns>The object value.</returns>
        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            if (reader.TokenType == JsonToken.Null)
            {
                return null;
            }

            UnionCase caseInfo = null;
            string caseName = null;
            JArray fields = null;

            // start object
            reader.ReadAndAssert();

            while (reader.TokenType == JsonToken.PropertyName)
            {
                string propertyName = reader.Value.ToString();
                if (string.Equals(propertyName, CasePropertyName, StringComparison.OrdinalIgnoreCase))
                {
                    reader.ReadAndAssert();

                    Union union = UnionCache.Get(objectType);

                    caseName = reader.Value.ToString();

                    caseInfo = union.Cases.SingleOrDefault(c => c.Name == caseName);

                    if (caseInfo == null)
                    {
                        throw JsonSerializationException.Create(reader, "No union type found with the name '{0}'.".FormatWith(CultureInfo.InvariantCulture, caseName));
                    }
                }
                else if (string.Equals(propertyName, FieldsPropertyName, StringComparison.OrdinalIgnoreCase))
                {
                    reader.ReadAndAssert();
                    if (reader.TokenType != JsonToken.StartArray)
                    {
                        throw JsonSerializationException.Create(reader, "Union fields must been an array.");
                    }

                    fields = (JArray)JToken.ReadFrom(reader);
                }
                else
                {
                    throw JsonSerializationException.Create(reader, "Unexpected property '{0}' found when reading union.".FormatWith(CultureInfo.InvariantCulture, propertyName));
                }

                reader.ReadAndAssert();
            }

            if (caseInfo == null)
            {
                throw JsonSerializationException.Create(reader, "No '{0}' property with union name found.".FormatWith(CultureInfo.InvariantCulture, CasePropertyName));
            }

            object[] typedFieldValues = new object[caseInfo.Fields.Length];

            if (caseInfo.Fields.Length > 0 && fields == null)
            {
                throw JsonSerializationException.Create(reader, "No '{0}' property with union fields found.".FormatWith(CultureInfo.InvariantCulture, FieldsPropertyName));
            }

            if (fields != null)
            {
                if (caseInfo.Fields.Length != fields.Count)
                {
                    throw JsonSerializationException.Create(reader, "The number of field values does not match the number of properties definied by union '{0}'.".FormatWith(CultureInfo.InvariantCulture, caseName));
                }

                for (int i = 0; i < fields.Count; i++)
                {
                    JToken t = fields[i];
                    PropertyInfo fieldProperty = caseInfo.Fields[i];

                    typedFieldValues[i] = t.ToObject(fieldProperty.PropertyType, serializer);
                }
            }

            object[] args = { typedFieldValues };

            return caseInfo.Constructor.Invoke(args);
        }

        /// <summary>
        /// Reads the JSON representation of the object.
        /// </summary>
        /// <param name="reader">The <see cref="JsonReader"/> to read from.</param>
        /// <param name="objectType">Type of the object.</param>
        /// <param name="existingValue">The existing value of object being read.</param>
        /// <param name="serializer">The calling serializer.</param>
        /// <returns>The object value.</returns>
        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            if (reader.TokenType == JsonToken.Null)
            {
                if (!ReflectionUtils.IsNullableType(objectType))
                {
                    throw JsonSerializationException.Create(reader, "Cannot convert null value to KeyValuePair.");
                }

                return null;
            }

            object key = null;
            object value = null;

            reader.ReadAndAssert();

            Type t = ReflectionUtils.IsNullableType(objectType)
                ? Nullable.GetUnderlyingType(objectType)
                : objectType;

            ReflectionObject reflectionObject = ReflectionObjectPerType.Get(t);

            while (reader.TokenType == JsonToken.PropertyName)
            {
                string propertyName = reader.Value.ToString();
                if (string.Equals(propertyName, KeyName, StringComparison.OrdinalIgnoreCase))
                {
                    reader.ReadAndAssert();
                    key = serializer.Deserialize(reader, reflectionObject.GetType(KeyName));
                }
                else if (string.Equals(propertyName, ValueName, StringComparison.OrdinalIgnoreCase))
                {
                    reader.ReadAndAssert();
                    value = serializer.Deserialize(reader, reflectionObject.GetType(ValueName));
                }
                else
                {
                    reader.Skip();
                }

                reader.ReadAndAssert();
            }

            return reflectionObject.Creator(key, value);
        }

        private bool ReadMetadataProperties(JsonReader reader, ref Type objectType, ref JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, object existingValue, out object newValue, out string id)
        {
            id = null;
            newValue = null;

            if (reader.TokenType == JsonToken.PropertyName)
            {
                string propertyName = reader.Value.ToString();

                if (propertyName.Length > 0 && propertyName[0] == '$')
                {
                    // read metadata properties
                    // $type, $id, $ref, etc
                    bool metadataProperty;

                    do
                    {
                        propertyName = reader.Value.ToString();

                        if (string.Equals(propertyName, JsonTypeReflector.RefPropertyName, StringComparison.Ordinal))
                        {
                            reader.ReadAndAssert();
                            if (reader.TokenType != JsonToken.String && reader.TokenType != JsonToken.Null)
                            {
                                throw JsonSerializationException.Create(reader, "JSON reference {0} property must have a string or null value.".FormatWith(CultureInfo.InvariantCulture, JsonTypeReflector.RefPropertyName));
                            }

                            string reference = (reader.Value != null) ? reader.Value.ToString() : null;

                            reader.ReadAndAssert();

                            if (reference != null)
                            {
                                if (reader.TokenType == JsonToken.PropertyName)
                                {
                                    throw JsonSerializationException.Create(reader, "Additional content found in JSON reference object. A JSON reference object should only have a {0} property.".FormatWith(CultureInfo.InvariantCulture, JsonTypeReflector.RefPropertyName));
                                }

                                newValue = Serializer.GetReferenceResolver().ResolveReference(this, reference);

                                if (TraceWriter != null && TraceWriter.LevelFilter >= TraceLevel.Info)
                                {
                                    TraceWriter.Trace(TraceLevel.Info, JsonPosition.FormatMessage(reader as IJsonLineInfo, reader.Path, "Resolved object reference '{0}' to {1}.".FormatWith(CultureInfo.InvariantCulture, reference, newValue.GetType())), null);
                                }

                                return true;
                            }
                            else
                            {
                                metadataProperty = true;
                            }
                        }
                        else if (string.Equals(propertyName, JsonTypeReflector.TypePropertyName, StringComparison.Ordinal))
                        {
                            reader.ReadAndAssert();
                            string qualifiedTypeName = reader.Value.ToString();

                            ResolveTypeName(reader, ref objectType, ref contract, member, containerContract, containerMember, qualifiedTypeName);

                            reader.ReadAndAssert();

                            metadataProperty = true;
                        }
                        else if (string.Equals(propertyName, JsonTypeReflector.IdPropertyName, StringComparison.Ordinal))
                        {
                            reader.ReadAndAssert();

                            id = (reader.Value != null) ? reader.Value.ToString() : null;

                            reader.ReadAndAssert();
                            metadataProperty = true;
                        }
                        else if (string.Equals(propertyName, JsonTypeReflector.ArrayValuesPropertyName, StringComparison.Ordinal))
                        {
                            reader.ReadAndAssert();
                            object list = CreateList(reader, objectType, contract, member, existingValue, id);
                            reader.ReadAndAssert();
                            newValue = list;
                            return true;
                        }
                        else
                        {
                            metadataProperty = false;
                        }
                    } while (metadataProperty && reader.TokenType == JsonToken.PropertyName);
                }
            }
            return false;
        }

        public void Populate(JsonReader reader, object target)
        {
            ValidationUtils.ArgumentNotNull(target, nameof(target));

            Type objectType = target.GetType();

            JsonContract contract = Serializer._contractResolver.ResolveContract(objectType);

            if (!reader.MoveToContent())
            {
                throw JsonSerializationException.Create(reader, "No JSON content found.");
            }

            if (reader.TokenType == JsonToken.StartArray)
            {
                if (contract.ContractType == JsonContractType.Array)
                {
                    JsonArrayContract arrayContract = (JsonArrayContract)contract;

                    PopulateList((arrayContract.ShouldCreateWrapper) ? arrayContract.CreateWrapper(target) : (IList)target, reader, arrayContract, null, null);
                }
                else
                {
                    throw JsonSerializationException.Create(reader, "Cannot populate JSON array onto type '{0}'.".FormatWith(CultureInfo.InvariantCulture, objectType));
                }
            }
            else if (reader.TokenType == JsonToken.StartObject)
            {
                reader.ReadAndAssert();

                string id = null;
                if (Serializer.MetadataPropertyHandling != MetadataPropertyHandling.Ignore
                    && reader.TokenType == JsonToken.PropertyName
                    && string.Equals(reader.Value.ToString(), JsonTypeReflector.IdPropertyName, StringComparison.Ordinal))
                {
                    reader.ReadAndAssert();
                    id = (reader.Value != null) ? reader.Value.ToString() : null;
                    reader.ReadAndAssert();
                }

                if (contract.ContractType == JsonContractType.Dictionary)
                {
                    JsonDictionaryContract dictionaryContract = (JsonDictionaryContract)contract;
                    PopulateDictionary((dictionaryContract.ShouldCreateWrapper) ? dictionaryContract.CreateWrapper(target) : (IDictionary)target, reader, dictionaryContract, null, id);
                }
                else if (contract.ContractType == JsonContractType.Object)
                {
                    PopulateObject(target, reader, (JsonObjectContract)contract, null, id);
                }
                else
                {
                    throw JsonSerializationException.Create(reader, "Cannot populate JSON object onto type '{0}'.".FormatWith(CultureInfo.InvariantCulture, objectType));
                }
            }
            else
            {
                throw JsonSerializationException.Create(reader, "Unexpected initial token '{0}' when populating object. Expected JSON object or array.".FormatWith(CultureInfo.InvariantCulture, reader.TokenType));
            }
        }

        private object CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, object existingValue)
        {
            string id;
            Type resolvedObjectType = objectType;

            if (Serializer.MetadataPropertyHandling == MetadataPropertyHandling.Ignore)
            {
                // don't look for metadata properties
                reader.ReadAndAssert();
                id = null;
            }
            else if (Serializer.MetadataPropertyHandling == MetadataPropertyHandling.ReadAhead)
            {
                JTokenReader tokenReader = reader as JTokenReader;
                if (tokenReader == null)
                {
                    JToken t = JToken.ReadFrom(reader);
                    tokenReader = (JTokenReader)t.CreateReader();
                    tokenReader.Culture = reader.Culture;
                    tokenReader.DateFormatString = reader.DateFormatString;
                    tokenReader.DateParseHandling = reader.DateParseHandling;
                    tokenReader.DateTimeZoneHandling = reader.DateTimeZoneHandling;
                    tokenReader.FloatParseHandling = reader.FloatParseHandling;
                    tokenReader.SupportMultipleContent = reader.SupportMultipleContent;

                    // start
                    tokenReader.ReadAndAssert();

                    reader = tokenReader;
                }

                object newValue;
                if (ReadMetadataPropertiesToken(tokenReader, ref resolvedObjectType, ref contract, member, containerContract, containerMember, existingValue, out newValue, out id))
                {
                    return newValue;
                }
            }
            else
            {
                reader.ReadAndAssert();
                object newValue;
                if (ReadMetadataProperties(reader, ref resolvedObjectType, ref contract, member, containerContract, containerMember, existingValue, out newValue, out id))
                {
                    return newValue;
                }
            }

            if (HasNoDefinedType(contract))
            {
                return CreateJObject(reader);
            }

            switch (contract.ContractType)
            {
                case JsonContractType.Object:
                {
                    bool createdFromNonDefaultCreator = false;
                    JsonObjectContract objectContract = (JsonObjectContract)contract;
                    object targetObject;
                    // check that if type name handling is being used that the existing value is compatible with the specified type
                    if (existingValue != null && (resolvedObjectType == objectType || resolvedObjectType.IsAssignableFrom(existingValue.GetType())))
                    {
                        targetObject = existingValue;
                    }
                    else
                    {
                        targetObject = CreateNewObject(reader, objectContract, member, containerMember, id, out createdFromNonDefaultCreator);
                    }

                    // don't populate if read from non-default creator because the object has already been read
                    if (createdFromNonDefaultCreator)
                    {
                        return targetObject;
                    }

                    return PopulateObject(targetObject, reader, objectContract, member, id);
                }
                case JsonContractType.Primitive:
                {
                    JsonPrimitiveContract primitiveContract = (JsonPrimitiveContract)contract;
                    // if the content is inside $value then read past it
                    if (Serializer.MetadataPropertyHandling != MetadataPropertyHandling.Ignore
                        && reader.TokenType == JsonToken.PropertyName
                        && string.Equals(reader.Value.ToString(), JsonTypeReflector.ValuePropertyName, StringComparison.Ordinal))
                    {
                        reader.ReadAndAssert();

                        // the token should not be an object because the $type value could have been included in the object
                        // without needing the $value property
                        if (reader.TokenType == JsonToken.StartObject)
                        {
                            throw JsonSerializationException.Create(reader, "Unexpected token when deserializing primitive value: " + reader.TokenType);
                        }

                        object value = CreateValueInternal(reader, resolvedObjectType, primitiveContract, member, null, null, existingValue);

                        reader.ReadAndAssert();
                        return value;
                    }
                    break;
//.........这里部分代码省略.........

        private static void ReadAndAssertProperty(JsonReader reader, string propertyName)
        {
            reader.ReadAndAssert();

            if (reader.TokenType != JsonToken.PropertyName || !string.Equals(reader.Value.ToString(), propertyName, StringComparison.OrdinalIgnoreCase))
            {
                throw new JsonSerializationException("Expected JSON property '{0}'.".FormatWith(CultureInfo.InvariantCulture, propertyName));
            }
        }