Serializing Your Structs Using XML

• Download source files - 4 Kb
• Download demo project - 15 Kb

Introduction

This article shows how to save a struct into an XML file (using STL), and load it back using Microsoft's MSXML 3.0 parser. If you have Microsoft's MSXML 4.0 parser installed, modify the stdafx.h file to use MSXML4 instead of MSXML3. This code can be modified to use a class instead of a struct.

Using the code

To implement this code in your project, add a call to initialize OLE support by inserting a call to ::AfxOleInit in the application class' InitInstance function. In my demo, this class is called CSerializeApp.

BOOL CSerializeApp::InitInstance()
{
   AfxEnableControlContainer();

   .
   .
   .

   ::AfxOleInit();

   // Since the dialog has been closed, return FALSE so that we exit the
   //  application, rather than start the application's message pump.
   return FALSE;
}

To import the Microsoft XML Parser typelib (OLE type library), add the following lines before the stdafx.h file's closing #endif. directive.

#import <msxml3.dll> named_guids
using namespace MSXML2;

Replace the 3 in msxml3.dll above with 4, if you have Microsoft's MSXML 4.0 parser installed.

In addition, include the following to the stdafx.h file, right before the #import above:

#include <atlbase.h>         // Needed for CComVariant.

Add the files SerializeXML.cpp/h to your project and modify the structs and function names to suit your needs.

Finally, call the save/load functions you added to save/load your structures to XML files. Example code follows:

   // Create a structure of type "first".
   {
      FirstStruct first;
      FirstSub1Struct firstSub1;
      FirstSub2Struct firstSub2;
      unsigned short i;
 
      first.someName = _T("Struct 1");
      first.someNumber = 1;

      for (i = 0; i < 16; ++i)
      {
         firstSub1.someNumber = i;
         _TCHAR buff[100];
         _stprintf(buff, _T("Struct 1 - %d"), i);
         firstSub1.someName = buff;
         first.firstSub1.push_back(firstSub1);
      }

      for (i = 0; i < 4; ++i)
      {
         firstSub2.someNumber = i;
         _TCHAR buff[100];
         _stprintf(buff, _T("Struct 1 - %d"), i);
         firstSub2.someName = buff;
         first.firstSub2.push_back(firstSub2);
      }

      mainStruct.first.push_back(first);
   }

   // Create another structure of type "first".
   {
      FirstStruct first;
      FirstSub1Struct firstSub1;
      FirstSub2Struct firstSub2;
      unsigned short i;
 
      first.someName = _T("Struct 2");
      first.someNumber = 1;

      for(i = 0;i < 16; ++i)
      {
         firstSub1.someNumber = i;
         _TCHAR buff[100];
         _stprintf(buff, _T("Struct 2 - %d"), i);
         firstSub1.someName = buff;
         first.firstSub1.push_back(firstSub1);
      }

      for(i = 0;i < 4; ++i)
      {
         firstSub2.someNumber = i;
         _TCHAR buff[100];
         _stprintf(buff, _T("Struct 2 - %d"), i);
         firstSub2.someName = buff;
         first.firstSub2.push_back(firstSub2);
      }

      mainStruct.first.push_back(first);
   }

   // Add "second" struct to main structure.
   SecondStruct secondStruct;
   secondStruct.someNumber1 = 1;
   secondStruct.someNumber2 = 2;
   mainStruct.second.push_back(secondStruct);
   secondStruct.someNumber1 = 2;
   secondStruct.someNumber2 = 4;
   mainStruct.second.push_back(secondStruct);
   secondStruct.someNumber1 = 3;
   secondStruct.someNumber2 = 6;
   mainStruct.second.push_back(secondStruct);

   // We have a complete structure ready for serialization.
   CSerializeXML serializeXML;

   serializeXML.SaveConfigurationToDisk("Test.xml", &mainStruct);
   serializeXML.LoadConfigurationFromDisk("Test.xml", &mainStruct2);
   serializeXML.SaveConfigurationToDisk("Test2.xml", &mainStruct2);

Points of Interest

Introduction to Using the XML DOM from Visual C++ by Tom Archer.

History

May 5, 2003 - article created.

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