help please!!

ok guys i really need u to have a look at this.
... my prob. is when i remove a quanitity or cost from their lstBoxs, the totals should be subtracted from that quantity or cost. but instead both totals go up by one???



Private Sub cmdRemove_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdRemove.Click


If lstProduct.SelectedIndex <> -1 Then
quantity = CDbl(lstQuantity.SelectedIndex)
totalQuantity = Val(lblTotalQuantity.Text) - quantity
lblTotalQuantity.Text = CStr(totalQuantity)
totalQuantity = 0 ' Intialising totalQuantity


totalCost = CDec(Val(lblTotalCost.Text) - lstCost.SelectedIndex)
lblTotalCost.Text = CStr(totalCost)
totalCost = 0 ' initialising totalcost

lstQuantity.Items.RemoveAt(lstProduct.SelectedIndex)
lstCost.Items.RemoveAt(lstProduct.SelectedIndex)
lstProduct.Items.RemoveAt(lstProduct.SelectedIndex)

Else
MsgBox("PLease select an item to be removed")

End If

End Sub

also i changed to something like this:
quantity = CDbl(lstProduct.SelectedIndex) , but it doesnot do any subtractions...

thanks

Hello aerohaith,

I see this is your second post on this problem. Maybe you could explain in some detail what your trying to do. Then once we can get what your trying to do I'm sure you'll get the help your looking for.

i'm trying to get the quatities& costs totals to work ,when an item has been deleted. the logic is when an item get deteled ,then the total quantity and total cost should be reduced as an item has just been removed. so basically , i would like to that.

what happens with this code ,is an item is removed ,but the totals go up by one , instead of its being reduced

i already answered this question once.

lstCost.SelectedIndex and the other one returning -1 becasue you dont hve an item selected in those listboxes.

a subtracting -1 from a number is the same as +1

Hello,

Ok I rewote a few section and this works here.

VB Code:

' declare some form level vars
  Dim dTotalQuantity, dTotalCost As Double
 
  Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Dim I As Integer
   
    ' didn't need the loop or select case but it was fun
    For I = 0 To 2
   
      Select Case I
        Case 0
          lstProduct.Items.Add("Computers")
          lstCost.Items.Add("1500.00")
          lstQuantity.Items.Add("5")
 
        Case 1
          lstProduct.Items.Add("Cell Phones")
          lstCost.Items.Add("150")
          lstQuantity.Items.Add("13")
 
        Case 2
          lstProduct.Items.Add("Optical Mouse")
          lstCost.Items.Add("10")
          lstQuantity.Items.Add("25")
      End Select
    Next I
 
    ' get the values
    For I = 0 To lstProduct.Items.Count - 1
      dTotalCost += lstCost.Items.Item(I)
      dTotalQuantity += lstQuantity.Items.Item(I)
    Next
    
    ' show the values
    lblTotalCost.Text = dTotalCost
    lblTotalQuantity.Text = dTotalQuantity
 
  End Sub
 
 
  Private Sub cmdRemove_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdRemove.Click
    Dim dQuantity, dProductCost As Double
    
    ' do some work
    If lstProduct.SelectedIndex <> -1 Then
      dQuantity = lstQuantity.SelectedItem
      dTotalQuantity = dTotalQuantity - dQuantity
      lblTotalQuantity.Text = dTotalQuantity
 
      dTotalCost = Convert.ToDouble(lblTotalCost.Text)
      dTotalCost = dTotalCost - lstCost.SelectedItem
      lblTotalCost.Text = dTotalCost.ToString
 
      lstQuantity.Items.RemoveAt(lstProduct.SelectedIndex)
      lstCost.Items.RemoveAt(lstProduct.SelectedIndex)
      lstProduct.Items.RemoveAt(lstProduct.SelectedIndex)
 
    Else
      MsgBox("PLease select an item to be removed")
 
    End If
  End Sub
  
  Private Sub lstProduct_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lstProduct.SelectedIndexChanged
 
    ' just to make sure we have all the items selected
    ' if the other listbox's are used by the user
    ' you may want to add similare code in those
    ' listboxes as well
    lstQuantity.SelectedIndex = lstProduct.SelectedIndex
    lstCost.SelectedIndex = lstProduct.SelectedIndex
 
  End Sub
 
 
End Class

Hope this helps a little.

Here you are Ithink this is what you are looking for

Private Sub cmdRemove_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdRemove.Click

Dim Index As Integer = lstProduct.SelectedIndex


If lstProduct.SelectedIndex = -1 Then
MsgBox("Please Select a Product")
Exit Sub
End If
'remove
lstProduct.Items.RemoveAt(lstProduct.SelectedIndex)
totalSum = totalSum - CDbl(lstCost.Items(Index))
txtTotalCost.Text = CStr(totalSum)
totalQuantity = totalQuantity - CDbl(lstQuantity.Items(Index))
txtTotalQuantity.Text = CStr(totalQuantity)
lstCost.Items.RemoveAt(Index)
lstQuantity.Items.RemoveAt(Index)


End Sub