remove and reset button for item list - vb.net

Question

I am trying to create a remove selected item and reset button which removes an item from a list box and reduces the cost of that item in a label. However, The clear button resets the cost and item list text but when clicking a button to add the item again it adds it once into the textbox but brings back the original cost as well as adding the new cost. The Remove selected item button removes the item but not the amount of the cost of that item. What am i doing wrong? Apologies for the bad English.GUI
Option Strict On
Public Class sandwichInterface
Dim DecTotal As Decimal
Private Sub btnCiabatta_Click(sender As Object, e As EventArgs) Handles btnCiabatta.Click
ListBox1.Items.Add("1 Ciabatta £1.50")
ListBox1.Text = ListBox1.Text + ("1 Ciabatta £1.50") + Chr(13)
DecTotal = DecTotal + CDbl(Microsoft.VisualBasic.Right("1 Ciabatta £1.50", 4))
lblTotal.Text = "Total £" + Format(DecTotal, "###.00")
End Sub
Private Sub btnRemove_Click(sender As Object, e As EventArgs) Handles btnRemove.Click
ListBox1.Items.Remove(ListBox1.SelectedItem)
If ListBox1.SelectedItem.Text = "1 Ciabatta £1.50" Then DecTotal = DecTotal - CDbl(Microsoft.VisualBasic.Right("1 Ciabatta £1.50", 4))
lblTotal.Text = "Total £" + Format(DecTotal, "###.00")
End Sub
Private Sub btnClear_Click(sender As Object, e As EventArgs) Handles btnClear.Click
ListBox1.Items.Clear()
If DecTotal = lblTotal.Text Then lblTotal.Text = "£0.00"
End Sub
End Class

Answer 1

Urgh, it pains me to even read this code but here goes!
Delete this from the add:
ListBox1.Text = ListBox1.Text + ("1 Ciabatta £1.50") + Chr(13)
Swap these 2 lines round, you can't check the value of the selected item after you removed it.:
ListBox1.Items.Remove(ListBox1.SelectedItem)
If ListBox1.SelectedItem.Text = "1 Ciabatta £1.50" Then DecTotal = DecTotal - CDbl(Microsoft.VisualBasic.Right("1 Ciabatta £1.50", 4))
By this:
If DecTotal = lblTotal.Text Then lblTotal.Text = "£0.00"
I can only guess you mean
DecTotal = 0
lblTotal.Text = "£0.00"
I also have no idea why you would do this:
If ListBox1.SelectedItem.Text = "1 Ciabatta £1.50" Then DecTotal = DecTotal - CDbl(Microsoft.VisualBasic.Right("1 Ciabatta £1.50", 4))
Instead of:
If ListBox1.SelectedItem.Text = "1 Ciabatta £1.50" Then DecTotal = DecTotal - 1.50
Even if the latter is still pretty awful!
Your whole approach to this is not nice though, passing around money as part of a string and using Microsoft.VisualBasic.Right and Cdbl to convert it to a float is pretty awful practice to say the least.

Answer 2

This code is not meant to paste into your project but to show you how some things could be done. I created a simple class to add objects to the list box. The Button2.Click shows how you could add items to your list box. You would add them one by one probably from Button events. Button 2 also shows how to get a total for the price. The $ before the string means that it is an interpolated string that can include variables. The :c after Total formats Total to local currency.
The button3.click shows how to remove an item from the list and adjust the total.
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
ListBox3.Items.Clear()
With ListBox3.Items
.Add(New FoodItem("Ciabatta", 1.5))
.Add(New FoodItem("Good Bread", 0.5))
.Add(New FoodItem("Great Bread", 2.0))
End With
For Each item As FoodItem In ListBox3.Items
Total += item.Price
Next
lblTotal.Text = $"{Total:c}"
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Dim SelectedFoodItem As FoodItem = DirectCast(ListBox3.SelectedItem, FoodItem)
Dim d As Double = SelectedFoodItem.Price
ListBox3.Items.Remove(ListBox3.SelectedItem)
Total -= d
lblTotal.Text = $"{Total:c}"
End Sub
End Class
Public Class FoodItem
Public Sub New()
'Default
End Sub
Public Sub New(objFoodName As String, dblPrice As Double)
FoodName = objFoodName
Price = dblPrice
End Sub
Private _FoodName As String
Public Property FoodName As String
Get
Return _FoodName
End Get
Set(value As String)
_FoodName = value
End Set
End Property
Private _Price As Double
Public Property Price As Double
Get
Return _Price
End Get
Set(value As Double)
_Price = value
End Set
End Property
Public Overrides Function ToString() As String
Return $"{_FoodName} {_Price:c}"
End Function
End Class