Value cannot be null. Parameter name: source in sdk 10.2.7

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03-19-2019 08:34 AM
murrayGordon
New Contributor

I had written an application a few years ago using .net sdk 10.2.7. It was working fine a few years ago. i came back to trying to use it now,but when it try it now. it is giving an error of Value cannot be null. Parameter name: source when calling the Dim routeResult = Await routeTask.SolveAsync(routeParams)

Was something changed in the API?

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6 Replies
ThadTilton
Esri Contributor

My guess would be that something has changed with the service/data that you're using for the route task (or the inputs). If you share a bit of the offending code, I can give it a test on my end.

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murrayGordon
New Contributor

I even tried using previous data that i used before for testing when it was working with the same issue.

Here is the code

                Dim routeGraphics = TryCast(MyMap.Layers("RouteResults"), GraphicsLayer)
                If routeGraphics Is Nothing Then
                    Throw New Exception("A graphics layer named 'RouteResults' was not found in the map.")
                End If

                Dim uri = New Uri("http://route.arcgis.com/arcgis/rest/services/World/Route/NAServer/Route_World")
                Dim routeTask = New OnlineRouteTask(uri)

                Dim RouteRestrictions = New List(Of String)
                RouteRestrictions.Add("Avoid Toll Roads")

                Dim routeParams = Await routeTask.GetDefaultParametersAsync()
                routeParams.OutSpatialReference = MyMapView.SpatialReference
                routeParams.DirectionsLengthUnit = LinearUnits.Miles
                routeParams.ReturnDirections = True
                routeParams.DirectionsLanguage = New CultureInfo("en-Us")
                routeParams.FindBestSequence = CBool(OptOptimized.IsChecked)
                routeParams.PreserveFirstStop = CBool(PreserveStopsCbx.IsChecked)
                routeParams.PreserveLastStop = CBool(PreserveStopsCbx.IsChecked)
                routeParams.UseHierarchy = Not CBool(CbxAvoidHwy.IsChecked)

                If (CbxAvoidToll.IsChecked) Then
                    routeParams.RestrictionAttributeNames = RouteRestrictions
                End If
                routeParams.ReturnStops = True
                routeParams.SetStops(routeGraphics.Graphics)

                Dim routeResult = Await routeTask.SolveAsync(routeParams)

It gives that error on the last line

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ThadTilton
Esri Contributor

Hey Murray.

I tested your code and saw the same thing. I tried using the following (San Diego) route service, and it worked as expected: Route (NAServer) 

I think the problem might be with authenticating for the service ("Route_World" is a premium service that you must sign in for). I tried using world routing service in this sample: https://github.com/Esri/arcgis-runtime-samples-dotnet/tree/master/src/WPF/ArcGISRuntime.WPF.Viewer/S... and after authenticating with my ArcGIS Online account, the route was solved successfully.

I'm not sure what may have changed to cause your code to fail. A couple of guesses: perhaps you had authentication "baked in" to your app and those credentials are no longer valid or perhaps your app was originally using a different (openly available) route service.

If you need to add authentication to your app, this sample may help (sorry, C# only): https://github.com/Esri/arcgis-runtime-samples-dotnet/tree/10.2.7/src/Desktop/ArcGISRuntimeSamplesDe...

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murrayGordon
New Contributor

It does appear related to the authentication. I am using the code below.

        Private ArcGISOnineUser As String = "xxx"
        Private ArcGISOninePassword As String = "xxx"

 Public Sub New()

            Esri.ArcGISRuntime.ArcGISRuntimeEnvironment.ClientId = "xxx"
            Esri.ArcGISRuntime.ArcGISRuntimeEnvironment.Initialize()

            InitializeComponent()

            IdentityManager.Current.ChallengeHandler = New ChallengeHandler(AddressOf CreateHardCodedCredentialAsync)

    end sub   

Private Async Function CreateHardCodedCredentialAsync(requestInfo As CredentialRequestInfo) As Task(Of Credential)
            Dim cred As Credential = Nothing
            Try
                Dim options = New GenerateTokenOptions()
                options.TokenAuthenticationType = TokenAuthenticationType.ArcGISToken
                cred = Await IdentityManager.Current.GenerateCredentialAsync(requestInfo.ServiceUri, ArcGISOnineUser, ArcGISOninePassword, options)
            Catch webEx As ArcGISWebException
                ' couldn't generate a token, probably a bad login  
                MessageBox.Show("Unable to log in to ArcGIS Online: " + webEx.Message)
            End Try
            Return cred
        End Function

After some investigation it seems that GenerateCredentialAsync never seems to return anything and the task seems to run indefinitely.

as a test it tried having it wait for the task completion

            Dim cred As Task(Of Credential) = CreateHardCodedCredentialAsync2("https://www.arcgis.com/sharing/rest")
            Try
                cred.Wait()
            Catch ex As Exception
                MsgBox(ex.Message)
            End Try

In this case it would just be stuck on cred.Wait() forever

CreateHardCodedCredentialAsync2 is just there to replace the requestInfo.ServiceUri

I tried running the sample in  https://github.com/Esri/arcgis-runtime-samples-dotnet/tree/10.2.7/src/Desktop/ArcGISRuntimeSamplesDe..., but when i clicked sign in all it did is display a page saying

Invalid redirect_uri

Error: 400
i left the default         private const string StandardAppDesktopRedirectUri = "urn:ietf:wg:oauth:2.0:oob"; as i don't have a landing page.and just filled in my client id.
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dotMorten_esri
Esri Frequent Contributor
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murrayGordon
New Contributor

Forcing TLS 1.2 via

System.Net.ServicePointManager.SecurityProtocol = System.Net.SecurityProtocolType.Tls12 and switching the project to .Net Framework 4.7 doesn't seem to help.

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