Calculate values in strings - vb.net

Question

I need to calculate labels values and I want the result to be formatted with 2 decimals digits.
The code I'm using is:
Dim culture = CultureInfo.CreateSpecificCulture("us-US")
Dim diff = CDec(CStr((Decimal.Parse(Label13.Text, culture) * Decimal.Parse(Label16.Text, culture)))) - Decimal.Parse(Label15.Text, culture)
If diff > 0 Then
Label20.ForeColor = Color.Green
Label20.Text = CStr(diff) '((CDbl(Label13.Text) * CDbl(Label16.Text)) - CDbl(Label15.Text)).ToString("n2")
Else
Label20.ForeColor = Color.Red
Label20.Text = CStr(diff) '((CDbl(Label13.Text) * CDbl(Label16.Text) - CDbl(Label15.Text))).ToString("n2")
End If
The input is:
label13.text= 0,600
label15.text=11,157
label16.text= 18,110
label20.text should be= -0,29
instead, the output im getting is
label20.text= - 4462,800
Where it comes from?
It s quite weird cause with this input it's working
label13.text= 1000
label15.text=107,4
label16.text= 0.10296
label20.text= -4.44
Thanks
Edit1:
Imports System.Globalization
Imports System.Net
Imports Newtonsoft.Json
Public Class Form1
'DICHIARO I WEBCLIENT
Private ReadOnly wcBTT As New WebClient()
Private ReadOnly wcUNI As New WebClient()
Private ReadOnly wcVET As New WebClient()
Private ReadOnly wcCAKE As New WebClient()
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Label4.Text = My.Settings.BTTQ
Label5.Text = My.Settings.BTTP
Label6.Text = My.Settings.BTTINV
Label7.Text = My.Settings.UNIQ
Label8.Text = My.Settings.UNIP
Label9.Text = My.Settings.UNIINV
Label10.Text = My.Settings.VETQ
Label11.Text = My.Settings.VETP
Label12.Text = My.Settings.VETINV
Label13.Text = My.Settings.CAKEQ
Label14.Text = My.Settings.CAKEP
Label15.Text = My.Settings.CAKEINV
End Sub
Private Async Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
'FERMO IL TIMER ALTRIMENTI OPERAZIONI I/O SIMULTANEE
Timer1.Stop()
Dim downloadTasks As New List(Of Task(Of String))
' SCARICO IL CONTENUTO DELLE API E LO DICHIARO "DIM BTC AS TASK(OF STRING)
Dim btt = wcBTT.DownloadStringTaskAsync("https://api.binance.com/api/v1/ticker/24hr?symbol=BTTBUSD")
Dim uni = wcUNI.DownloadStringTaskAsync("https://api.binance.com/api/v1/ticker/24hr?symbol=UNIBUSD")
Dim vet = wcVET.DownloadStringTaskAsync("https://api.binance.com/api/v1/ticker/24hr?symbol=VETBUSD")
Dim cake = wcCAKE.DownloadStringTaskAsync("https://api.binance.com/api/v1/ticker/24hr?symbol=CAKEBUSD")
downloadTasks.Add(btt)
downloadTasks.Add(uni)
downloadTasks.Add(vet)
downloadTasks.Add(cake)
Await Task.WhenAll(downloadTasks)
'DESERIALIZZO LE API NORMALI
Dim settings = New JsonSerializerSettings With {.Culture = CultureInfo.InvariantCulture}
Dim d = JsonConvert.DeserializeObject(Of Dictionary(Of String, String))(btt.Result, settings)
Dim d1 = JsonConvert.DeserializeObject(Of Dictionary(Of String, String))(uni.Result, settings)
Dim d2 = JsonConvert.DeserializeObject(Of Dictionary(Of String, String))(vet.Result, settings)
Dim d3 = JsonConvert.DeserializeObject(Of Dictionary(Of String, String))(cake.Result, settings)
Dim PREZZOBTT As Decimal = Decimal.Parse(CStr(d("lastPrice")), CultureInfo.InvariantCulture)
Dim PREZZOUNI As Decimal = Decimal.Parse(CStr(d1("lastPrice")), CultureInfo.InvariantCulture)
Dim PREZZOVET As Decimal = Decimal.Parse(CStr(d2("lastPrice")), CultureInfo.InvariantCulture)
Dim PREZZOCAKE As Decimal = Decimal.Parse(CStr(d3("lastPrice")), CultureInfo.InvariantCulture)
'CONNETTO LE API NORMALI ALLE LABEL
Label1.Text = PREZZOBTT.ToString("n7")
Label2.Text = PREZZOUNI.ToString("n3")
Label3.Text = PREZZOVET.ToString("n5")
Label16.Text = PREZZOCAKE.ToString("n3")
'GAIN/LOSS
'BTT
Dim diffbtt = (PREZZOBTT * Decimal.Parse(Label4.Text) - Decimal.Parse(Label6.Text)).ToString("n2")
If CInt(diffbtt) > 0 Then
Label17.ForeColor = Color.Green
Label17.Text = CStr(diffbtt)
Else
Label17.ForeColor = Color.Red
Label17.Text = CStr(diffbtt) '
End If
''UNI
Dim diffuni = (Decimal.Parse(Label7.Text) * PREZZOUNI - Decimal.Parse(Label9.Text)).ToString("n2")
If CInt(diffuni) > 0 Then
Label18.ForeColor = Color.Green
Label18.Text = CStr(diffuni)
Else
Label18.ForeColor = Color.Red
Label18.Text = CStr(diffuni) '
End If
''VET
Dim diffvet = (PREZZOVET * Decimal.Parse(Label10.Text) - Decimal.Parse(Label12.Text)).ToString("n2")
If CInt(diffvet) > 0 Then
Label19.ForeColor = Color.Green
Label19.Text = CStr(diffvet)
Else
Label19.ForeColor = Color.Red
Label19.Text = CStr(diffvet) '
End If
''CAKE
Dim diffcake = (Decimal.Parse(Label13.Text) * PREZZOCAKE - Decimal.Parse(Label15.Text)).ToString("n2")
If CInt(diffcake) > 0 Then
Label20.ForeColor = Color.Green
Label20.Text = CStr(diffcake)
Else
Label20.ForeColor = Color.Red
Label20.Text = CStr(diffcake)
End If
Timer1.Start()
End Sub

Answer 1

I would drop Decimal type, use Double, and use the string Format command for ensuring 2 digit precision in the results of the delta (diff). The parsing can take a string argument, so you don't need to convert to CDbl() first -- besides, how can you convert to double if you are trying to determine if what's being tested is double? The return from Format is a string result, so it doesn't need CStr(), .ToString, etc.
Dim lab3, lab5, lab6, diff As Double
Dim parseresult As Object
If Double.TryParse(Label3.Text, parseresult) = True Then
lab3 = CDbl(Label3.Text)
End If
If Double.TryParse(Label5.Text, parseresult) = True Then
lab5 = CDbl(Label5.Text)
End If
If Double.TryParse(Label6.Text, parseresult) = True Then
lab6 = CDbl(Label6.Text)
End If
diff = lab3 * lab6 - lab5
If diff > 0 Then
Label20.ForeColor = Color.Green
Label20.Text = Format(diff, "0.00"))
Else
Label20.ForeColor = Color.Red
Label20.Text = Format(diff, "0.00")
End If
If you need to kill the currency type, i.e., if "$" is in the label strings, then replace it with
lab3str = Label3.Text.Replace("$","")
and then parse lab3str.