(MFC) JSON: Miscellaneous Operations

Demonstrates a variety of JSON API methods. This example uses the following JSON document:

{
   "alphabet": "abcdefghijklmnopqrstuvwxyz",
   "sampleData" : {
           "pi": 3.14,
	   "apple": "juicy",
	   "hungry": true,
	   "withoutValue": null,
           "answer": 42
          
	}
}

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkJsonObject.h>

void ChilkatSample(void)
    {
    CkString strOut;

    CkJsonObject json;
    json.put_EmitCompact(false);

    // Assume the file contains the data as shown above..
    bool success = json.LoadFile("qa_data/json/sample2.json");
    if (success != true) {
        strOut.append(json.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // First navigate to the "sampleData" object:
    CkJsonObject *sampleData = json.ObjectOf("sampleData");

    // Demonstrate BoolAt and BoolOf
    strOut.append("hungry: ");
    strOut.appendInt(sampleData->BoolOf("hungry"));
    strOut.append("\r\n");
    strOut.append("hungry: ");
    strOut.appendInt(sampleData->BoolAt(2));
    strOut.append("\r\n");

    // StringOf returns the value as a string regardless of it's actual type:
    strOut.append("pi: ");
    strOut.append(sampleData->stringOf("pi"));
    strOut.append("\r\n");
    strOut.append("answer: ");
    strOut.append(sampleData->stringOf("answer"));
    strOut.append("\r\n");
    strOut.append("withoutValue: ");
    strOut.append(sampleData->stringOf("withoutValue"));
    strOut.append("\r\n");
    strOut.append("hungry: ");
    strOut.append(sampleData->stringOf("hungry"));
    strOut.append("\r\n");

    // Demonstrate IsNullOf / IsNullAt
    strOut.append("withoutValue is null? ");
    strOut.appendInt(sampleData->IsNullOf("withoutValue"));
    strOut.append("\r\n");
    strOut.append("withoutValue is null? ");
    strOut.appendInt(sampleData->IsNullAt(3));
    strOut.append("\r\n");
    strOut.append("apple is null? ");
    strOut.appendInt(sampleData->IsNullOf("apple"));
    strOut.append("\r\n");
    strOut.append("apple is null? ");
    strOut.appendInt(sampleData->IsNullAt(1));
    strOut.append("\r\n");

    // IntOf
    strOut.append("answer: ");
    strOut.appendInt(sampleData->IntOf("answer"));
    strOut.append("\r\n");

    // SetNullAt, SetNullOf
    // Set "pi" to null
    success = sampleData->SetNullAt(0);
    // Set "answer" to null
    success = sampleData->SetNullOf("answer");

    // Show the changes:
    strOut.append(json.emit());
    strOut.append("\r\n");

    // Restore pi and apple:
    success = sampleData->SetNumberAt(0,"3.14");
    success = sampleData->SetNumberOf("answer","42");

    // Show the changes:
    strOut.append(json.emit());
    strOut.append("\r\n");

    // Add a null value named "afterApple" just after "apple"
    success = sampleData->AddNullAt(2,"afterApple");

    // Add a boolean value just after "pi"
    success = sampleData->AddBoolAt(1,"afterPi",false);

    delete sampleData;

    // Examine the changes..
    strOut.append(json.emit());
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }