(MFC) Get the Root of a JSON Document

Demonstrates how to get back to the JSON root object from anywhere in the JSON document. This example uses the following JSON document:

{
  "flower": "tulip",
  "abc":
    {
    "x": [
       { "a" : 1 },
       { "b1" : 100, "b2" : 200 },
       { "c" : 3 }
    ],
    "y": 200,
    "z": 200
    }
}

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;

    const char *jsonStr = "{\"flower\": \"tulip\",\"abc\":{\"x\": [{ \"a\" : 1 },{ \"b1\" : 100, \"b2\" : 200 },{ \"c\" : 3 }],\"y\": 200,\"z\": 200}}";

    bool success = json.Load(jsonStr);
    if (success != true) {
        strOut.append(json.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Get the "abc" object.
    CkJsonObject *abcObj = json.ObjectOf("abc");
    if (json.get_LastMethodSuccess() == false) {
        strOut.append("abc object not found.");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Side note: The JSON of a sub-part of the document can be emitted from any JSON object:
    abcObj->put_EmitCompact(false);
    strOut.append(abcObj->emit());
    strOut.append("\r\n");

    // Navigate to the "x" array
    CkJsonArray *xArray = abcObj->ArrayOf("x");
    // We'll skip the null check and assume it's non-null...

    // Navigate to the 2nd object contained within the array.  This contains members b1 and b2
    CkJsonObject *bObj = xArray->ObjectAt(1);
    // We'll skip the null check and assume it's non-null...

    // Show that we're at "b1/b2".
    // The value of "b1" should be "200"
    strOut.append("b2 = ");
    strOut.appendInt(bObj->IntOf("b2"));
    strOut.append("\r\n");

    // Now go back to the JSON doc root:
    CkJsonObject *docRoot = bObj->GetDocRoot();
    // We'll skip the null check and assume it's non-null...

    // Pretty-print the JSON doc from the root to show that this is indeed the root.
    docRoot->put_EmitCompact(false);
    strOut.append(docRoot->emit());
    strOut.append("\r\n");

    delete docRoot;
    delete bObj;
    delete xArray;
    delete abcObj;


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }