divide by zero while entering a numeric value that begins with 0

basically I have a textbox

Code:

---

    Private Sub txt_NumberA_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txt_NumberA.TextChanged
       
        Try
            NumberA = Decimal.Parse(txt_NumberA.Text)
        Catch ex As Exception
            MsgBox("This program requires a numeric input.  Please try again. Enter .500 as 0.500.")
            Return
        End Try
       
        NumberB = 5.0
       
      NumberC = NumberB/NumberA

lbl_NumberC.Text = NumberC

    End Sub

---

I have no problem entering any number that does not start with a zero, however, if I want to enter 0.5 in, then as I type in '0', then I have division by zero and the program crashes.

Could you please help me to fix this? Many thanks,

Nina

Try this:

Code:

---

    Private Sub txt_NumberA_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txt_NumberA.TextChanged
        If Val(txt_NumberA.Text) <> 0 Then
            Try
                numbera = Decimal.Parse(txt_NumberA.Text)
            Catch ex As Exception
                MsgBox("This program requires a numeric input. Please try again. Enter .500 as 0.500.")
                Return
            End Try

            numberb = 5.0

            numberc = numberb / numbera

            lbl_NumberC.Text = numberc
        End If
    End Sub

---

03myersd,
It worked, thank you very much.
Nina

Quote:

---

Originally Posted by 03myersd

Try this:

Code:

---

    Private Sub txt_NumberA_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txt_NumberA.TextChanged
        If Val(txt_NumberA.Text) <> 0 Then
            Try
                numbera = Decimal.Parse(txt_NumberA.Text)
            Catch ex As Exception
                MsgBox("This program requires a numeric input. Please try again. Enter .500 as 0.500.")
                Return
            End Try

            numberb = 5.0

            numberc = numberb / numbera

            lbl_NumberC.Text = numberc
        End If
    End Sub

---

---

If the user is going to type in 53 your code displays in lbl_NumberC.Text the following:
1.0
.09

Is that what you wanted or did you just want the .09? If so you are in the wrong event handler, and also why you had the problem with 0.

I'd say you are in the wrong event handler, too. Re-doing the calculation for every character being entered means lots of extra work. LostFocus might be a better place.

However, this code will be faster. Catching an exception is a painfully slow process (though there is no cost if no exception is thrown), so using TryParse will produce better average results than dealing with an exception.

vb Code:

Private Sub txt_NumberA_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txt_NumberA.TextChanged
        
        if not Decimal.TryParse(txt_NumberA.Text,NumberA)
         MsgBox("This program requires a numeric input.  Please try again. Enter .500 as 0.500.")
            Return
        End if
        
        NumberB = 5.0
        
        if NumberA<>0 then
         NumberC = NumberB/NumberA
        else
         NumberC=0
        end if
 
lbl_NumberC.Text = NumberC.ToString
 
    End Sub