(MFC) Modify Parts of JSON Document

Demonstrates how to modify parts of a JSON document. This example uses the following JSON document:

{
   "fruit": [
      	{
         "kind": "apple",
	 "count": 24,
	 "fresh": true,
	 "extraInfo": null,
	 "listA": [ "abc", 1, null, false ],
	 "objectB": { "animal" : "monkey" }
      	},
	{
         "kind": "pear",
	 "count": 18,
	 "fresh": false,
	 "extraInfo": null
	 "listA": [ "xyz", 24, null, true ],
	 "objectB": { "animal" : "lemur" }
	}
    ],
    "list" : [ "banana", 12, true, null, "orange", 12.5, { "ticker": "AAPL" }, [ 1, 2, 3, 4, 5 ] ],
    "alien" : true
}

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

See Also: Using MFC CString in Chilkat

#include <CkJsonObject.h>
#include <CkJsonArray.h>

void ChilkatSample(void)
    {
    CkString strOut;

    CkJsonObject json;

    // Load the JSON from a file.
    bool success = json.LoadFile("qa_data/json/modifySample.json");
    if (success != true) {
        strOut.append(json.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // This example will not check for errors (i.e. null / false / 0 return values)...

    // Get the "list" array:
    CkJsonArray *listA = json.ArrayOf("list");

    // Modify values in the list.

    // Change banana to plantain
    success = listA->SetStringAt(0,"plantain");

    // Change 12 to 24
    success = listA->SetIntAt(1,24);

    // Change true to false
    success = listA->SetBoolAt(2,false);

    // Is the 3rd item null?
    bool bNull = listA->IsNullAt(3);

    // Change "orange" to 32.
    success = listA->SetIntAt(4,32);

    // Change 12.5 to 31.2
    success = listA->SetNumberAt(5,"31.2");

    // Replace the { "ticker" : "AAPL" } object with { "ticker" : "GOOG" }
    // Do this by deleting, then inserting a new object at the same location.
    success = listA->DeleteAt(6);
    success = listA->AddObjectAt(6);
    CkJsonObject *tickerObj = listA->ObjectAt(6);
    success = tickerObj->AddStringAt(-1,"ticker","GOOG");

    delete tickerObj;

    // Replace "[ 1, 2, 3, 4, 5 ]" with "[ "apple", 22, true, null, 1080.25 ]"
    success = listA->DeleteAt(7);
    success = listA->AddArrayAt(7);
    CkJsonArray *aa = listA->ArrayAt(7);
    success = aa->AddStringAt(-1,"apple");
    success = aa->AddIntAt(-1,22);
    success = aa->AddBoolAt(-1,true);
    success = aa->AddNullAt(-1);
    success = aa->AddNumberAt(-1,"1080.25");
    delete aa;

    delete listA;

    // Get the "fruit" array
    CkJsonArray *aFruit = json.ArrayAt(0);

    // Get the 1st element:
    CkJsonObject *appleObj = aFruit->ObjectAt(0);

    // Modify values by member name:
    success = appleObj->SetStringOf("fruit","fuji_apple");
    success = appleObj->SetIntOf("count",46);
    success = appleObj->SetBoolOf("fresh",false);
    success = appleObj->SetStringOf("extraInfo","developed by growers at the Tohoku Research Station in Fujisaki");

    delete appleObj;

    // Modify values by index:
    CkJsonObject *pearObj = aFruit->ObjectAt(1);
    success = pearObj->SetStringAt(0,"bartlett_pear");
    success = pearObj->SetIntAt(1,12);
    success = pearObj->SetBoolAt(2,false);
    success = pearObj->SetStringAt(3,"harvested in late August to early September");
    delete pearObj;

    delete aFruit;

    json.put_EmitCompact(false);
    strOut.append(json.emit());
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }