toast notification throwing unhandlend exception in background agent wp8

Question

I have a background agent on my app that works well until I send a toast notification, it throws an unhandled exception with the exception object message being: "Object reference not set to an instance of an object." The OnInvoke method is async as I do async request that works perfectly. The piece of code that throws the exception is the following

            ShellToast toast = new ShellToast();
            toast.Title = "hello";
            toast.Show();

I have no clue on where the issue might be, thanks in advance for the help.

Edit: Here is the Stacktrace:

at Microsoft.Phone.Shell.ShellToast.Show()
at ScheduledTaskAgent1.ScheduledAgent.<OnInvoke>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.AsyncMethodBuilderCore.   <ThrowAsync>b__4(Object state)
at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
at System.Threading.ThreadPoolWorkQueue.Dispatch()
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()

Answer 1

You can use another simple toast, just go to NuGet Packages, search for Toastinet and install it or download it from here .

After download add its namespace to .xaml file as below

xmlns:toastinet="clr-namespace:Toastinet;assembly=Toastinet"

and declaretion of toast is as below

<toastinet:Toastinet Grid.ColumnSpan="2" x:Name="myToast"
                          Duration="1"
                         Height="50"
                         FontSize="20"
                          Margin="0,10,0,0"
                          ShowLogo="False"
                         AnimationType="Vertical"
                         Background="#FFFFFF "
                         Foreground="#4e0916"
                         TextWrapping="Wrap"
                         Canvas.ZIndex="1"
                         VerticalAlignment="Top" />

And use this toast anywhere in .cs. as below

this.myToast.Message="hello";