Visual FoxPro

Get the Index of a JSON Member

See more JSON Examples

This example demonstrates how to get the index of a given member by name.

{
  "name": "donut",
  "image":
    {
    "fname": "donut.jpg",
    "w": 200,
    "h": 200
    },
  "thumbnail":
    {
    "fname": "donutThumb.jpg",
    "w": 32,
    "h": 32
    }
}

Visual FoxPro

LOCAL lnSuccess
LOCAL loJson
LOCAL lcJsonStr
LOCAL lnNameIndex
LOCAL lnThumbIndex
LOCAL lnFnameIndex
LOCAL loImageObj

lnSuccess = 0

loJson = CreateObject('Chilkat.JsonObject')

* This is the above JSON with whitespace chars removed (SPACE, TAB, CR, and LF chars).
* The presence of whitespace chars for pretty-printing makes no difference to the Load
* method. 
lcJsonStr = '{"name": "donut","image":{"fname": "donut.jpg","w": 200,"h": 200},"thumbnail":{"fname": "donutThumb.jpg","w": 32,"h": 32}}'

lnSuccess = loJson.Load(lcJsonStr)
IF (lnSuccess = 0) THEN
    ? loJson.LastErrorText
    RELEASE loJson
    CANCEL
ENDIF

* The top-level JSON object has three members: name, image, and thumbnail.
lnNameIndex = loJson.IndexOf("name")
* The index of the "name" member is 0.
? "nameIndex = " + STR(lnNameIndex)

lnThumbIndex = loJson.IndexOf("thumbnail")
* The index of the "thumbnail" member is 2.
? "thumbIndex = " + STR(lnThumbIndex)

* The "fname" member is NOT a direct member of the top-level JSON object.
* It is a member of a nested object.  If we try to get the index of this
* member using the top-level JSON object, it is not found (and returns -1).
lnFnameIndex = loJson.IndexOf("fname")
* The fnameIndex is -1 (not found).  This is correct.
? "fnameIndex = " + STR(lnFnameIndex)

* Get the "image" object.
loImageObj = CreateObject('Chilkat.JsonObject')
loJson.ObjectOf2("image",loImageObj)

* Now we can get the index of the "fname" object, because it is a direct
* member of the "image" object:
lnFnameIndex = loImageObj.IndexOf("fname")
? "fnameIndex = " + STR(lnFnameIndex)

RELEASE loJson
RELEASE loImageObj