Problema VB.Net " Conversion from string "Salve, vorrei" to type 'double' is not vali

[Crax]

Innanzitutto salve!!!
Quando eseguo il programma, mi appare l' errore scritto sopra. Nel log esce scritto anche"A first chance exception of type 'System.InvalidCastException' occurred in Microsoft.VisualBasic.dll".
Il codice è questo:

Public Class Form1
Dim wurtot As Decimal
Private Sub WPmeno_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles WPmeno.Click
wurtot = wurtot - 1
WPrisult.Text = wurtot


End Sub

Private Sub WPiu_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles WPiu.Click
wurtot = wurtot + 1
WPrisult.Text = wurtot

End Sub

Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs)

End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
tot.Text = ("Salve, vorrei ") + wurtot + ("Wurstel e patatine")
End Sub
End Class

Inoltre il compilatore localizza l' errore qui:

 "tot.Text = ("Salve, vorrei ") + wurtot + ("Wurstel e patatine")"

Come posso correggere il problema?.