Weather Alerts Refusing to Display In List Box

Question

Hello,

I have a weather application that uses a list box and a ticker to display weather information. However, the list box refuses to display any bit of information while the ticker remains functioning.

Here is my code:

 Private Sub NOAA_Alerts()

        Using WB As New WebClient
            Try
                WB.Headers.Add("User-Agent", "AWNHD Weather Broadcast Engine/v1.0 (website; email")
                WB.Headers.Add(HttpRequestHeader.Accept, "application/atom+xml")
                Dim WXData As String = WB.DownloadString($"https://api.weather.gov/alerts/active?zone={My.Settings.Wx_Alerts}")
                If WXData <> LastWXData Then
                    LastWXData = WXData
                    ListBox3.Items.Clear()
                    ListBox3.Enabled = False
                    WXDict.Clear()
                    XmlDoc.LoadXml(WXData)
                    Dim TitleList As XmlNodeList = XmlDoc.GetElementsByTagName("title")
                    Dim CapEvents As XmlNodeList = XmlDoc.GetElementsByTagName("cap:event")
                    Dim CapEventsForColor As XmlNodeList = XmlDoc.GetElementsByTagName("cap:event")
                    Dim SummaryList As XmlNodeList = XmlDoc.GetElementsByTagName("summary")
                    Dim MsgTypeList As XmlNodeList = XmlDoc.GetElementsByTagName("cap:msgType")
                    Dim MsgExpire As XmlNodeList = XmlDoc.GetElementsByTagName("cap:expires")
                    Dim geocode As XmlNodeList = XmlDoc.GetElementsByTagName("cap:areaDesc")

                    For i = 1 To TitleList.Count - 1
                        WXDict.Add(TitleList(i).InnerText, SummaryList(i - 1).InnerText)
                        Label49.Text = TitleList(i).InnerText
                    Next

                    AlertText.Text = Regex.Replace(SummaryList(0).InnerText.Trim(), "(\s*(\r\n|\r|\n)\s*)+", " ")
                    AlertTitle.Text = CapEvents(0).InnerText
                    Label28.Text = CapEvents(0).InnerText
                    Label50.Text = MsgExpire(0).InnerText
                    Label53.Text = geocode(0).InnerText
                    My.Settings.AlertTickerColor = CapEvents(0).InnerText
                    My.Settings.LFIAlert1 = CapEvents(0).InnerText
                    My.Settings.Alert_Message_Title = CapEvents(0).InnerText
                    If MsgTypeList(0).InnerText = "Update" Then
                        AlertTitle.Text = CapEvents(0).InnerText + " Update"
                    End If

                    'If Label53.Text.Contains(My.Settings.CountyName) Then
                    'Panel1.Visible = True
                    'Else
                    '   Panel1.Visible = False
                    'End If

                    'If geocode.Count = 0 Then
                    'Panel1.Visible = False
                    'End If

                    If AlertTitle.Text = "Severe Thunderstorm Warning Update" Then
                        AlertTitle.Text = "Severe T-Storm Warning Update"
                    End If
                    ListBox3.Items.AddRange(WXDict.Keys.ToArray)
                    ListBox3.Enabled = True
                    ListBox3.SelectedIndex = 0

                End If
            Catch ex As Exception
                'MsgBox(ex.Message + " - NOAA_Alerts")
            End Try
        End Using
    End Sub
    Dim LastWXData As String = ""

I have tried everything I can think of. It has something to do with the WxDict not loading. I didn't change any code prior to this and it worked flawlessly. What is going on and how can I fix it? Thanks!

Answer 1

Hello @Austin Althouse

Have you considered using json as a return type with classes to represent the returning json?

If open to this, add NuGet package Newtonsoft.json -> Install-Package Newtonsoft.Json -Version 12.0.3

The following was done in a Console project but you can work with this with Windows Forms or WPF. The code is basic code sample showing how to get at various pieces of data strongly typed. I don't iterate each item but there is enough to learn from.

Classes

Public Class Geocode  
	Public Property UGC() As List(Of String)  
	Public Property SAME() As List(Of String)  
End Class  
  
Public Class Reference  
	<JsonProperty("@id")>  
	Public Property Id() As String  
	Public Property identifier() As String  
	Public Property sender() As String  
	Public Property sent() As DateTime  
End Class  
  
Public Class Parameters  
	Public Property NWSheadline() As List(Of String)  
	Public Property VTEC() As List(Of String)  
	Public Property PIL() As List(Of String)  
	Public Property BLOCKCHANNEL() As List(Of String)  
	Public Property eventEndingTime() As List(Of DateTime)  
	Public Property HazardType() As List(Of String)  
	<JsonProperty("EAS-ORG")>  
	Public Property EASORG() As List(Of String)  
End Class  
  
Public Class Properties  
	<JsonProperty("@id")>  
	Public Property Id() As String  
	<JsonProperty("@type")>  
	Public Property Type() As String  
	Public Property areaDesc() As String  
	Public Property geocode() As Geocode  
	Public Property affectedZones() As List(Of String)  
	Public Property references() As List(Of Reference)  
	Public Property sent() As DateTime  
	Public Property effective() As DateTime  
	Public Property onset() As DateTime  
	Public Property expires() As DateTime  
	Public Property ends() As DateTime  
	Public Property status() As String  
	Public Property messageType() As String  
	Public Property category() As String  
	Public Property severity() As String  
	Public Property certainty() As String  
	Public Property urgency() As String  
	Public Property [event]() As String  
	Public Property sender() As String  
	Public Property senderName() As String  
	Public Property headline() As String  
	Public Property description() As String  
	Public Property instruction() As String  
	Public Property response() As String  
	Public Property parameters() As Parameters  
End Class  
  
Public Class Feature  
	Public Property id() As String  
	Public Property type() As String  
	Public Property geometry() As Object  
	Public Property properties() As Properties  
End Class  
  
Public Class Root  
	<JsonProperty("@context")>  
	Public Property Context() As List(Of Object)  
	Public Property type() As String  
	Public Property features() As List(Of Feature)  
	Public Property title() As String  
	Public Property updated() As DateTime  
End Class  

Reading back data

Using webClient As New WebClient  
  
	webClient.Headers.Add("User-Agent", "AWNHD Weather Broadcast Engine/v1.0 (website; email")  
  
	Dim json As String = webClient.DownloadString("https://api.weather.gov/alerts/active?area=OR")  
  
	Dim results As Root = JsonConvert.DeserializeObject(Of Root)(json)  
  
	Console.WriteLine($"Title: {results.title}")  
  
	For Each feature As Feature In results.features  
  
		Console.WriteLine($"Event: {feature.properties.event} " &  
						  $"Type: {feature.properties.Type.Replace("wx:", "")}")  
  
		Console.WriteLine($"   Description: {feature.properties.description}")  
  
		Console.WriteLine(New String("-"c, 30))  
  
		Console.WriteLine($"{vbTab}Affected zones")  
  
		For Each affectedZone As String In feature.properties.affectedZones  
			Console.WriteLine($"{vbTab}{vbTab}{affectedZone}")  
		Next  
  
		Console.WriteLine()  
  
		Console.WriteLine($"{vbTab}geocode.SAME")  
  
		For Each s As String In feature.properties.geocode.SAME  
			Console.WriteLine($"{vbTab}{vbTab}{s}")  
		Next  
  
		Console.WriteLine()  
  
	Next  
  
End Using