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C++ FromJsonFile - CXmlObjectBase
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void FromJsonFile(LPCTSTR lpszFileName)
void FromJsonFile(LPCTSTR lpszFileName, const CSerialiaztionContext& context)
  Property Description  
    Method Name FromJsonFile  
    Argument - lpszFileName The JSON file to be de-serialized. This can be an Json document or Fast Infoset document and can be a compressed gzip or zlib file.  
    Argument - context

The CSerializationContext object controls the way in which JSON is serialized/de-serialized. Its main role is to control the way in which validation is performed and which namespaces are output.
If this is not specified, the a default (CSerializationContext::Default global static) instance of the class is used. If you are using several libraries generated from different schemas, or you want to change the way validation is performed for during the lifetime of the application or you are writing multithreaded code, then you should consider creating your own instance(s) of the CSerializationContext.

Note: If you are writing a multithreaded app it is highly recommended that you use a different instance of this class on each thread, as access to the static instance is not synchronized. Although read only operations to the static instance (CSerializationContext::Default) of the class are thread safe, if the global instance CSerializationContext::Default is modified, then this could potentially cause threading problems.

 
    Description De-Serializes an JSON file into the current object.  
    Remarks

This method will only load JSON that complies with the XSD schema.
It will raise an exception if the JSON is invalid.

The root element in the JSON held within lpszJSONIn must correspond to the class which this method is being called on. So you have a simple schema.

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/JSONSchema"
           elementFormDefault="qualified"
           attributeFormDefault="unqualified">
  <xs:element name="Person">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="name" type="xs:string"/>
        <xs:element name="Address">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="HouseNumber" type="xs:string"/>
              <xs:element name="PostCode" type="xs:string"/>
            </xs:sequence>
          </xs:complexType>
        </xs:element>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>


This would cause 2 classes to be generated CPerson & CAddress.
So if you had the JSON file test.xml, which contained.

{
  "Person": {
    "name": "Joe Blogs",
    "Address": {
      "HouseNumber": "15",
      "PostCode": "LS5 9PQ"
    }
  }
}


You would call FromJson on a CPerson object ie

CPersonPtr spPerson = CPerson::CreateInstance();
spPerson->FromJsonFile("c:\\test.xml")
;

Character encoding.
The underlying parser is expat version 1.95.6, as supports the following character encodings

  • UTF-8
  • UTF-16
  • UNICODE

See Multi-Language Support and Global Functions for more information.