GordonB GordonB - 1 month ago 9
Vb.net Question

Deserializing json array into .net class

I'm having problems deserializing some json data, getting InvalidCastExceptions and the like.

Can anyone point me in the right direction?

Here's the json i'm wanting to deserialize;


[{"OrderId":0,"Name":"Summary","MaxLen":"200"},{"OrderId":1,"Name":"Details","MaxLen":"0"}]


Here's my code;

Public Class jsTextArea
Public OrderId As Integer
Public Name As String
Public MaxLen As String
End Class

Dim js As New System.Web.Script.Serialization.JavaScriptSerializer
Dim rawdata = js.DeserializeObject(textAreaJson)
Dim lstTextAreas As List(Of jsTextArea) = CType(rawdata, List(Of jsTextArea))

Rob Rob
Answer

OrderId is an Int in your json (note the lack fo quotes round the values), but you're declaring it as String in "jsTextArea". Also, unless the type that rawdata is returned as has a cast to List(Of jsTextArea), which it probably doesn't the code you've shown won't work.

Update To get the data out into a List(Of jsTextArea) try the following:

    Dim js As New System.Web.Script.Serialization.JavaScriptSerializer
    Dim lstTextAreas = js.Deserialize(Of List(Of jsTextArea))(textAreaJson)