Question

I have the following functions.
When I call getQueryObject(jsonString) It makes the coll parses the object then returns.
The the assignment to jsonObject is not working. When I start operating on the jsonObject bariable it has the value nothing.
I run Debug and follow the code and the jsonObject in getQueryObject is not failing. and return says it returns the object.

I am new to VB is there something I am missing?

Public Function getInformation(jsonString as string) as string
    Dim jsonObject As JObject
    jsonObject = getQueryObject(jsonString)
    'Operate on object here.
End Function

Private Function getQueryObject(jsonString as string) As JObject
    Dim jsonObject As JObject
    Try
        jsonObject = JObject.Parse(jsonString)

    Catch ex As Exception
        jsonObject = New JObject
    End Try
    Return jsonObject
End Function

A little more information. After I turned on Option strict I started to get an error. Option Strict On disallows implicit conversions from ‘Newtonsoft.Jsont.Linq.Token to Newtonsoft.Json.Linq.JObject’.

I don’s see where I am making any type of conversion.

Answer 1

The problem is that you’ve used in the incorrect variable name in the getInformation function.

Change your code to look like this, instead:

Public Function GetInformation(jsonString as string) as string
    Dim jsonObj As JObject
    jsonObj = GetQueryObject(jsonString)  // Change the name of this variable
                                          // to match the declaration above it.
    'Operate on object here.
End Function

Or even simpler, declare and initialize the variable in the same line:

Public Function GetInformation(jsonString as string) as string
    Dim jsonObj As JObject = GetQueryObject(jsonString)
    'Operate on object here.
End Function

If you were compiling your code with Option Explicit and Option Strict both turned on, the compiler would have caught this problem for you. Change those settings in your project’s Properties. NEVER write code in VB.NET with Option Explicit turned off. Unexpected things happen.

What’s happening is that VB.NET is letting you use the jsonObject variable without ever declaring it. The compiler just automagically initializes it to Nothing behind the scenes, which is the default value. It’s a simple enough mistake to make, since that’s the name of the variable in the other method. But it doesn’t work as expected, because it’s not the name of the variable in this method. As long as you haveOption Explicit off, VB.NET doesn’t warn you, and blissfully compiles wrong code.

(Note that I’m also following the recommended .NET coding convention of CamelCasing all method names. That means they should start with a capital letter, rather than a lower-case letter. Only local variables and parameters should be pascalCased (initial lower-case).)