VB.NET

Modify Parts of JSON Document

See more JSON Examples

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
}

VB.NET

Dim success As Boolean = False

Dim json As New Chilkat.JsonObject

' Load the JSON from a file.
success = json.LoadFile("qa_data/json/modifySample.json")
If (success = False) Then
    Debug.WriteLine(json.LastErrorText)
    Exit Sub
End If


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

' Get the "list" array:

Dim listA As New Chilkat.JsonArray

json.ArrayOf2("list",listA)

' 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?
Dim bNull As Boolean = 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)
Dim tickerObj As New Chilkat.JsonObject
listA.AddObjectAt2(6,tickerObj)

success = tickerObj.AppendString("ticker","GOOG")

' Replace "[ 1, 2, 3, 4, 5 ]" with "[ "apple", 22, true, null, 1080.25 ]"
success = listA.DeleteAt(7)
Dim aa As New Chilkat.JsonArray
listA.AddArrayAt2(7,aa)

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")

' Get the "fruit" array
Dim aFruit As New Chilkat.JsonArray
json.ArrayAt2(0,aFruit)

' Get the 1st element:
Dim appleObj As New Chilkat.JsonObject
aFruit.ObjectAt2(0,appleObj)

' 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")

' Modify values by index:

Dim pearObj As New Chilkat.JsonObject
aFruit.ObjectAt2(1,pearObj)

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")

json.EmitCompact = False
Debug.WriteLine(json.Emit())